The Best Pre-Workout Ingredients, Ranked by Scientific Evidence
Joe Clark | BSc Hons Sport ScienceA long ingredient list does not necessarily make an effective pre-workout. Many formulas include promising ingredients at doses too low to match the research, while others rely on ingredients with little evidence for improving performance.
Unfortunately, that means many pre-workouts on the market are unlikely to deliver the level of performance benefit their labels suggest.
This guide ranks the most common pre-workout ingredients from Tier A to Tier D based on the strength of the scientific evidence, the dose required to work, and how much they actually contribute to performance, so you can make a more informed decision when choosing a pre-workout.
I wrote this as a resource you can come back to when you want to understand why a particular ingredient is included in a pre-workout, what it actually does, and whether the dose on the label is likely to be effective.
The tier list
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A Tier A: The Most Evidence-Based Pre-Workout Ingredients
Tier A contains the ingredients with the strongest and most consistent scientific evidence for improving exercise performance. Each has a well-established physiological mechanism, a clear effective dosing range and a substantial body of research supporting its use.
Caffeine
Function
Caffeine is a central nervous system stimulant that works primarily by blocking adenosine receptors in the brain. This increases alertness, reduces the perception of fatigue and effort, and improves both physical and cognitive performance during exercise.
Why is caffeine Tier A?
Caffeine has an exceptionally large and consistent body of evidence showing improvements across strength, power and endurance performance, with a clearly established effective dose range. It is also the one ingredient on this list whose benefit comes from taking it shortly before exercise, which makes it the ingredient a pre-workout is built around.
Scientific evidence
Caffeine is one of the most extensively researched performance-enhancing ingredients available.
A systematic review and meta-analysis of studies measuring one-repetition maximum strength (10 studies) and muscle power (10 studies) found that caffeine improved both by a small amount. For strength the benefit was significant for upper-body lifts but not lower-body lifts. [4]
A meta-analysis found that caffeine improved knee-extensor maximal voluntary contraction strength by about 7% and muscular endurance by about 18% in open-ended endurance tests. [1]
In a double-blind crossover study of 14 resistance-trained men, 5 mg/kg of caffeine produced 11.6% more total bench-press repetitions and 19.1% more total leg-press repetitions across three sets to failure compared with placebo. [3]
A systematic review and meta-analysis of 46 randomized, placebo-controlled studies on endurance time trials found that caffeine improved completion time by about 2.2% and mean power output by about 3.0% compared with placebo at moderate doses of 3 to 6 mg/kg. [2]
To put that in context, a 2.2% improvement is roughly 40 seconds over a 30-minute time trial, which at competitive level is a large margin.
Effective dose: 3 to 6 mg per kg of body weight
Most research uses 3 to 6 mg/kg, although around 3 to 4 mg/kg is enough to significantly improve performance in most people. For a 70 kg individual, 3 to 4 mg/kg is roughly 210 to 280 mg of caffeine, or about the amount in two to three cups of brewed coffee. Lower doses can still help, particularly for endurance exercise. Higher doses do not reliably produce greater benefits and are more likely to cause nervousness, stomach discomfort, sleep disruption and other stimulant-related side effects.
Should caffeine be in a pre-workout?
Yes. Of all the ingredients in this article, caffeine is the one that genuinely depends on timing: its effects peak within about 30 to 60 minutes of consumption and fade over the following few hours. That makes a pre-workout the logical place for it. The main things to check are that the dose is stated and that it suits your body weight and caffeine tolerance.
Creatine Monohydrate
Function
Creatine supplementation increases creatine and phosphocreatine stores within skeletal muscle. Phosphocreatine rapidly regenerates adenosine triphosphate (ATP), the body's immediate energy source for muscular contraction. Higher muscle creatine stores therefore improve the ability to regenerate ATP during repeated bouts of high-intensity exercise.
Why is creatine Tier A?
Creatine monohydrate is one of the most extensively researched performance supplements in existence. It has a large and consistent body of evidence showing improvements in strength, power, repeated high-intensity exercise performance and adaptations to resistance training.
Scientific evidence
A review of 22 studies found that when creatine was combined with resistance training, muscular strength increased by an average of 20%, compared with 12% for resistance training with placebo. Weightlifting performance, measured as maximal repetitions at a given percentage of maximal strength, increased by an average of 26% with creatine compared with 12% with placebo. [5]
In a 12-week double-blind study of resistance-trained men, bench press strength increased by 24% in the creatine group compared with 16% in the placebo group, and squat strength by 32% compared with 24%. Fat-free mass increased by 6.3% with creatine compared with 3.1% with placebo. [8]
In another double-blind study of trained male athletes, five days of creatine supplementation increased repetitions to fatigue by 21% in the bench press and 33% in the half-squat. Average power output increased by 17% and 20% respectively, and half-squat 1RM by 11%. The same study found a 5% improvement in countermovement jump after fatiguing resistance exercise and a 3% improvement over the first 5 metres of repeated 15-metre sprints. [6]
Creatine may also support endurance training and recovery through its effect on muscle glycogen, the primary carbohydrate fuel for prolonged and high-intensity exercise. After glycogen-depleting endurance exercise, combining creatine with a high-carbohydrate diet increased muscle glycogen resynthesis in the first 24 hours of recovery by about 82% compared with carbohydrate and placebo. [7]
A separate study found that prior creatine loading increased subsequent glycogen supercompensation: a carbohydrate-loading protocol raised muscle glycogen by 4% before creatine loading and by 53% when repeated after it, leaving total glycogen significantly higher. [9]
This is relevant to athletes training hard on consecutive days, where restoring glycogen matters for the next session.
Creatine may also have cognitive benefits. A 2024 systematic review and meta-analysis of 16 randomized controlled trials found significant improvements in memory, attention time and information-processing speed. The certainty of evidence was moderate for memory and lower for attention and processing speed. [10]
Effective dose: 3 to 5 g per day
Consuming 3 g of creatine per day for 28 days increased total muscle creatine by about 20%. A loading protocol of 20 g per day produced a similar increase in six days, showing that loading gets you there faster but is not necessary to reach the same level over time. [11]
For most people, 3 to 5 g of creatine monohydrate per day is an effective long-term dose. Larger doses may be better for cognitive performance outcomes, but this is still an emerging field of evidence.
Should creatine be in a pre-workout?
Not necessarily. Creatine's benefits come from keeping muscle stores elevated through consistent daily use, not from taking it immediately before training. It is also inexpensive and needs a relatively large 3 to 5 g dose, so including it in a pre-workout adds bulk to the formula without any benefit from the timing. Many pre-workouts include only 1 to 2 g, which is below the effective daily dose. Creatine is usually better taken as a standalone supplement, leaving the pre-workout to focus on ingredients that genuinely depend on being taken before exercise.
Beta-Alanine
Function
Beta-alanine is an amino acid the body uses to produce carnosine within skeletal muscle. Carnosine acts as an intracellular buffer, neutralizing the hydrogen ions that accumulate during high-intensity exercise. As hydrogen ions build up, muscle pH falls, contributing to fatigue and a reduced ability to sustain hard work. Raising muscle carnosine improves the muscle's ability to buffer that acidity and sustain high-intensity effort for longer.
Why is beta-alanine Tier A?
Beta-alanine has a well-established mechanism and a substantial body of research showing improvements in muscular endurance and high-intensity exercise capacity. Its benefits are most relevant during repeated high-volume resistance training and sustained efforts of roughly one to ten minutes, where muscle acidity is a major contributor to fatigue.
Scientific evidence
A meta-analysis of 15 studies with 360 participants found that beta-alanine produced an average 2.85% improvement across exercise outcomes. The benefit was clearest in exercise lasting 60 to 240 seconds, with a smaller benefit beyond 240 seconds; exercise under 60 seconds did not significantly improve. [12]
In a four-week pilot study of 16 resistance-trained men following the same training programme where every set was taken to failure, only the group taking 6.4 g of beta-alanine per day increased the total work it completed each week (a 6.5% rise from the first to the last week, from extra repetitions at the same loads), and it did so with a lower average rating of perceived exertion than the placebo group (8.8 versus 9.4 out of 10). It is a small study, but it shows the practical effect in a gym setting: a few more reps before failure, at a lower perceived effort. [13]
The effect builds with time. In a 24-week study, muscle carnosine had risen within four weeks of supplementation and kept climbing to 24 weeks (roughly 11 mmol/kg of dry muscle at four weeks and 20 mmol/kg at 24 weeks), alongside improved high-intensity cycling capacity. [16]
The benefits extend beyond the gym. In recreational runners, 28 days of beta-alanine improved 800 m time by 2.46%, compared with 0.37% in the placebo group. [14]
In physically active adults following the same three-week running programme, 10 km time improved by about 6.7% with beta-alanine (3441 to 3209 seconds) compared with a much smaller, non-significant change in the placebo group, with significantly lower blood lactate after the run. [15]
A 2024 systematic review and meta-analysis of 18 randomized, double-blind, placebo-controlled studies in 331 trained men found a small-to-moderate overall improvement in maximal-intensity exercise performance, with the strongest effect in efforts lasting 4 to 10 minutes. [17]
Effective dose: 3.2 to 6.4 g per day
Muscle carnosine rises in proportion to the total amount of beta-alanine taken over weeks, which is why daily consistency matters more than timing. Most performance research uses 4 to 6.4 g per day for at least four weeks; lower daily doses raise carnosine too, just more slowly. Splitting the daily amount into smaller doses reduces paraesthesia, the harmless tingling sensation beta-alanine is known for.
Should beta-alanine be in a pre-workout?
Only if the dose is right. Like creatine, beta-alanine works by accumulating in muscle over weeks of daily use. Taking it 30 minutes before a session does nothing on its own. Many pre-workouts include 1.6 to 2 g, which is enough to produce the tingle but, unless you take it every day including rest days, not enough to meaningfully raise carnosine. Many people take the tingle as a sign it is working. It is a harmless side effect, not a performance effect. If your pre-workout is your only source, check for at least 3.2 g per serving. Otherwise, a standalone beta-alanine taken daily is the more reliable option.
B Tier B: Promising Evidence, Less Consistent Results
Tier B contains ingredients with good evidence for a real but smaller performance benefit. Each has a plausible mechanism and several positive trials, but the research base is smaller than Tier A, the effects are less consistent between studies, and the benefit is often limited to specific outcomes rather than performance across the board.
L-Citrulline / Citrulline Malate
Function
L-citrulline increases circulating arginine concentrations, which can raise nitric oxide production. Nitric oxide widens blood vessels and increases blood flow, which may improve oxygen and nutrient delivery to working muscle and contributes to the increased muscle "pump" associated with citrulline. Citrulline may also support high-intensity exercise by helping clear ammonia through the urea cycle.
Citrulline malate is L-citrulline bound to malic acid, usually in a 2:1 ratio, so 8 g of citrulline malate provides roughly 5.3 g of L-citrulline. Most of the performance research has used the malate form.
Why is citrulline Tier B?
Citrulline has reasonable evidence for a small improvement in muscular endurance, meaning more repetitions before failure in high-volume resistance training. However, the effect is small, it is less consistent than the Tier A ingredients, and the evidence does not support improvements in maximal strength or endurance performance. The most recent and largest analysis rates the certainty of the evidence as low.
Scientific evidence
A systematic review and meta-analysis of eight placebo-controlled studies (137 participants) found that taking 6 to 8 g of citrulline malate 40 to 60 minutes before resistance training increased total repetitions by about 6.4% compared with placebo, around three extra repetitions across a workout. The effect was small, and in the separate upper- and lower-body analyses it did not reach statistical significance. [18]
In a randomized, double-blind crossover study of 41 men, 8 g of citrulline malate increased bench-press repetitions to failure from the third set onwards, with the gap widening as the session went on. In the final set, participants completed about 53% more repetitions than with placebo. Muscle soreness at 24 and 48 hours was reduced by about 40%. Around 15% of participants reported stomach discomfort. [20]
In 15 resistance-trained women, 8 g of citrulline malate increased total leg-press repetitions by about 21% across six sets to failure (66.7 versus 55.1). Bench-press repetitions also increased, but only by about one repetition across six sets (34.1 versus 32.9), and perceived exertion for the upper body was lower. [19]
The overall effect appears modest. A 2026 systematic review and meta-analysis of 30 randomized controlled trials (644 participants) found a small improvement in overall exercise performance with citrulline malate, with the certainty of evidence rated low to very low. In the subgroup analyses, neither strength and power nor repetitions to failure reached statistical significance, and the apparent benefits for aerobic and anaerobic performance disappeared when outlying studies were removed. Dose made no difference to the size of the effect. [21]
For endurance exercise, a meta-analysis of nine studies (158 participants) found no significant improvement in either time to exhaustion or time-trial performance after acute citrulline supplementation. [22]
Effective dose: 6 to 8 g of citrulline malate
Most studies reporting improvements in resistance-training performance used 6 to 8 g of citrulline malate taken 40 to 60 minutes before exercise. A minimum effective dose has not been firmly established, and the equivalent dose of pure L-citrulline is less well studied; at the usual 2:1 ratio, 6 to 8 g of citrulline malate works out to roughly 4 to 5 g of L-citrulline.
Should citrulline be in a pre-workout?
Yes, with a dose check. Unlike creatine and beta-alanine, citrulline's effect depends on taking it shortly before training, so a pre-workout is the right place for it. The problem is the amount. The research dose is 6 to 8 g of citrulline malate, and many pre-workouts contain 2 to 3 g, which is enough to list on the label but below anything that has been shown to work. If the label gives citrulline malate, look for 6 g or more; if it gives L-citrulline, look for 4 g or more.
Betaine Anhydrous
Function
Betaine acts as an osmolyte, helping cells maintain hydration and volume, and as a methyl donor involved in several metabolic processes. These properties may support muscular force production, cell function and adaptation to training, although the mechanism behind its performance effects is not fully understood.
Why is betaine Tier B?
Betaine has promising evidence for improving maximal strength, particularly lower-body strength, but the research base is small and the results are inconsistent. The most recent meta-analysis supports an effect on maximal strength while finding no significant effect on muscular endurance, upper-body strength, sprint power or bench-press throw power, and its own sensitivity analysis shows the lower-body result rests on a handful of studies.
Scientific evidence
A 2024 systematic review and meta-analysis of 17 studies (317 participants) found that at least seven days of betaine supplementation significantly improved maximal muscular strength by a moderate amount, with the clearest effect on lower-body strength. Vertical jump also improved once one low-quality study was excluded. There were no significant improvements in upper-body strength, muscular endurance, cycling sprint power or bench-press throw power. The lower-body strength effect was fragile: it was no longer statistically significant when any one of four individual studies was removed from the analysis, which is one reason betaine sits in Tier B rather than Tier A. [25]
A randomized, double-blind crossover study in 12 recreationally trained men found that 14 days of 2.5 g betaine per day increased bench-throw power by about 16% and isometric bench-press force by about 25% compared with pre-supplementation values. Isometric squat force also improved. However, repetitions to fatigue in the bench press and squat did not change, and squat-jump power was unaffected. [23]
A small double-blind crossover study in ten adolescent handball players (average age 16) with no prior resistance-training experience found very large improvements in muscular endurance after 14 days at 2.5 g per day: about 44% more leg-press repetitions and 39% more bench-press repetitions than placebo across five sets to fatigue. The improvements here are far larger than in any adult study, and the participants were young and untrained, so this result should be read as encouraging rather than typical. [24]
Effective dose: 2.5 g per day
Almost all of the resistance-training research showing positive effects has used 2.5 g of betaine per day, taken consistently for at least one to two weeks. Lower doses have not been studied for performance. [25]
Should betaine be in a pre-workout?
Only if you take it every day. Like creatine, betaine works by building up over a week or more of daily use, not from a single dose before training. A pre-workout that contains 2.5 g and that you take daily, including rest days, will deliver the research dose. One you take three times a week will not. If you want to try betaine, a standalone product taken daily is the more reliable route, and at around 2.5 g it is inexpensive.
Dietary Nitrate (Beetroot)
Function
Dietary nitrate, found in beetroot and leafy greens, is converted by bacteria in the mouth to nitrite and then to nitric oxide in the body. This lowers the amount of oxygen the muscles need for a given workload, improves blood flow and may improve the efficiency of muscle contraction. Because the conversion happens in the mouth, antibacterial mouthwash can blunt the effect.
Why is nitrate Tier B?
Nitrate has a large body of research, mostly in endurance exercise, and a clear mechanism. It reliably improves time to exhaustion and lowers the oxygen cost of exercise, but it does not consistently improve time-trial performance, the benefit is smaller in highly trained athletes, and the resistance-training research is still small. Its effect peaks 2 to 3 hours after a dose, so, like creatine and beta-alanine, it earns its tier on the strength of the evidence rather than on suiting pre-workout timing.
Scientific evidence
A 2021 systematic review and meta-analysis of 73 placebo-controlled studies (1,061 participants) found that nitrate increased time to exhaustion by about 25 seconds on average, increased power output and distance covered, and reduced oxygen consumption during exercise. Time-trial performance was not significantly improved. The authors rated the certainty of evidence as low. [26]
In the study that started the field, eight men who drank 500 ml of beetroot juice a day for six days cycled 92 seconds longer to exhaustion at a severe intensity (about 16% longer) than after placebo, with a 19% lower oxygen cost at the start of moderate exercise. [27]
For resistance training the evidence is early but encouraging. A 2020 systematic review of four studies (49 resistance-trained men) found that beetroot juice increased bench-press repetitions to failure by 10.7% to 19.4% in three of the four studies, with one study also reporting higher mean power. The one study testing squats found no change. [28]
Effective dose: 6 to 8 mmol of nitrate, 2 to 3 hours before exercise
The Australian Institute of Sport recommends 6 to 8 mmol (roughly 350 to 500 mg) of nitrate taken 2 to 3 hours before exercise, with the clearest benefit in efforts of 4 to 30 minutes and in recreational rather than elite athletes. That is the amount in about 70 ml of concentrated beetroot juice. Highly trained endurance athletes often see little benefit. [29]
Should nitrate be in a pre-workout?
Not as a 30-minutes-before ingredient. Nitrate peaks 2 to 3 hours after you take it, so a dose in a pre-workout taken 20 to 30 minutes before training has not done much by the time you start. It works if you take the product early or take it every day, which is the same rule as beta-alanine. The other problem is dosing: many products list "beetroot powder" without stating nitrate content, and ordinary beetroot powder varies enormously. If nitrate is listed in mg and you take the product daily or a couple of hours early, it is a worthwhile Tier B ingredient. Otherwise a concentrated beetroot shot taken on its own does the job better.
C Tier C: Plausible Mechanisms, Limited Or Situational Evidence
Tier C contains ingredients with plausible mechanisms and some positive human research, but where the evidence is inconsistent, situational or considerably less established than in Tiers A and B. These ingredients can still add value to a pre-workout, particularly for focus and cognitive performance or for specific types of exercise, but the research does not support treating them as essential performance ingredients.
L-Tyrosine
Function
L-tyrosine is an amino acid the body uses to make the catecholamine neurotransmitters dopamine and noradrenaline. During substantial physical or psychological stress, demand for these neurotransmitters rises, and supplemental tyrosine may help maintain their production. In a pre-workout its potential value is therefore cognitive rather than muscular: helping maintain attention, working memory and mental performance when fatigue or stress would otherwise impair them.
Why is L-tyrosine Tier C?
L-tyrosine has reasonable evidence for maintaining cognitive performance under stressful or fatiguing conditions such as sleep deprivation, cold exposure and demanding multitasking. However, the evidence for improving physical exercise performance is weak, the cognitive benefit appears mainly when the brain is under real strain, and most of the positive studies used doses considerably higher than those found in pre-workouts.
Scientific evidence
A review of 15 human studies found that tyrosine generally did not improve physical exercise performance. In the cognitive studies, tyrosine helped prevent declines in working memory and information processing when people were exposed to demanding conditions such as extreme weather or high cognitive load. [30]
A separate evidence review of 10 randomized controlled trials and four controlled clinical trials reached a similar conclusion: all six studies that tested cognition under stressful, catecholamine-depleting conditions (sleep deprivation, extreme climate, military training) found some benefit for attention, reaction time or memory. [32]
In a double-blind, placebo-controlled study of extended wakefulness, a 150 mg/kg dose of tyrosine (roughly 10 g for a 70 kg adult) significantly reduced the usual decline in psychomotor performance and reduced lapses on a sustained-attention task. The improvement lasted around three hours. [31]
The evidence is not all positive. A 2019 randomized, double-blind trial in 70 university students found that 2 g of tyrosine worsened cognitive flexibility (measured by reaction time on a card-sorting task) under high cognitive load, with no effect under low load. The effect was seen in reaction time only, not in error rates, but it shows that tyrosine's effects depend heavily on the situation and the dose. [33]
Effective dose: not firmly established
The strongest positive studies used around 100 to 150 mg per kg of body weight, which is 7 to 10.5 g for a 70 kg person. More recent cognitive studies have used around 2 g with mixed results. The 500 mg to 1 g doses common in pre-workouts have not been studied on their own, so their effect is not established either way.
Should L-tyrosine be in a pre-workout?
As a supporting ingredient rather than a performance one. Tyrosine's evidence is for maintaining mental performance under stress and fatigue, and the clearest results come from doses well above what a pre-workout can practically contain. At 1 g it is safe, inexpensive and plausible as part of a focus blend alongside caffeine, but you should not expect a measurable performance effect from it on its own. If you often train sleep-deprived or under heavy stress and want to test tyrosine properly, a larger standalone dose is the version the research actually looked at.
L-Theanine
Function
L-theanine is an amino acid found naturally in tea that influences several neurotransmitter systems in the brain. In pre-workouts it is used almost always alongside caffeine, with the aim of supporting attention and focus while producing a calmer stimulant experience.
Why is L-theanine Tier C?
L-theanine has increasingly good evidence for improving certain aspects of attention and reaction time, both alone and combined with caffeine. However, there is little evidence that it directly improves strength, power, endurance or any other physical exercise outcome. Its value in a pre-workout is as a cognitive-support ingredient, not a performance one.
Scientific evidence
A 2026 systematic review and meta-analysis of 31 randomized controlled trials (1,168 participants) found that a single 200 mg dose of L-theanine, taken 30 to 60 minutes before testing, produced a moderate improvement in choice reaction time. The effect on acute stress was smaller and was largely driven by studies at high risk of bias. [34]
A 2025 systematic review of 50 randomized controlled trials found that combining L-theanine with caffeine produced small improvements in the second hour after supplementation: about 1.1 percentage points better accuracy on an attention-switching test and 1.6 points on a sustained-attention test. L-theanine on its own improved choice reaction time in the first hour. The authors described the overall evidence as uncertain, with few studies eligible for pooling and wide confidence intervals. [35]
In a study of 16 healthy adults, 100 mg of L-theanine combined with 50 mg of caffeine improved accuracy on a visuospatial attention task, while neither ingredient alone differed from placebo. [36]
Effective dose: 100 to 200 mg
Most acute cognitive research has used 100 to 200 mg of L-theanine, alone or with caffeine. Much of the combination research used a 2:1 ratio of theanine to caffeine (100 mg with 50 mg), whereas pre-workouts typically pair 100 to 200 mg of theanine with 200 to 300 mg of caffeine; whether the calming effect holds at that ratio is less well studied. There is no established dose for exercise performance because L-theanine has not been shown to improve it.
Should L-theanine be in a pre-workout?
Yes, if you value focus and a smoother caffeine experience, and it costs little to include. It will not make you stronger or faster. Its job is to improve attention and reduce the jittery edge of a high-caffeine formula, and the evidence for that is reasonable at 100 to 200 mg. If you prefer the full effect of caffeine on its own, you lose nothing by skipping it.
Alpha-GPC
Function
Alpha-GPC (alpha-glycerylphosphorylcholine) is a concentrated source of choline. Choline is needed to produce acetylcholine, a neurotransmitter involved in attention, memory and the signalling between nerves and muscles. Increasing choline availability could therefore in theory support both cognitive performance and muscular force production.
Why is Alpha-GPC Tier C?
Alpha-GPC has some promising evidence for improving cognition and certain measures of force and power, which makes it an interesting pre-workout ingredient. However, the exercise literature is small, the results conflict with each other, and some of the strongest positive findings come from studies of 12 to 20 people. The evidence is not strong enough to place it alongside established performance ingredients.
Scientific evidence
In a randomized, double-blind, placebo-controlled crossover study of 13 college-aged men, six days of 600 mg Alpha-GPC significantly increased lower-body isometric force compared with placebo, an improvement the authors describe as greater than 3%. Upper-body force trended upward but did not reach statistical significance. [37]
A seven-day study in 48 recreationally trained men (12 per group) compared 250 mg and 500 mg of Alpha-GPC with caffeine and placebo. Countermovement-jump power improved in the 250 mg group, but neither Alpha-GPC dose improved isometric mid-thigh pull strength (only caffeine did) or psychomotor vigilance. The authors note the small groups and the need for replication. [39]
A 2024 randomized, double-blind, placebo-controlled crossover study in 20 resistance-trained men found that single doses of both 315 mg and 630 mg of Alpha-GPC significantly improved performance on the Stroop cognitive test compared with placebo. On the physical side, the 630 mg dose produced significantly greater peak force in a bench-press throw, but neither dose improved vertical jump, bench-press-throw power or velocity, or the other physical measures. [38]
Taken together, Alpha-GPC appears able to influence cognition acutely and may improve isolated measures of force or power, but these findings have not been shown consistently across a large body of research.
Effective dose: 300 to 600 mg
The exercise and cognitive studies showing benefits used 250 to 630 mg. A minimum effective dose has not been established, but 300 to 600 mg is the most defensible range on current evidence.
Should Alpha-GPC be in a pre-workout?
Worth including for focus. The evidence for physical performance is still thin. The 2024 study is useful here because it shows a cognitive effect from a single dose taken before testing, which is exactly how a pre-workout is used. Check the amount: at 150 to 200 mg, which is common, you are below every study that found anything. At 300 mg or more you are in the range that has been tested.
Taurine
Function
Taurine is an amino sulfonic acid involved in several processes relevant to exercise, including calcium handling within muscle cells, cell-volume regulation, membrane stability and antioxidant activity. These functions may support muscle contraction, fatigue resistance and endurance performance.
Why is taurine Tier C?
Taurine has promising evidence for improving endurance and some other measures of exercise performance, but the effects are small and the research is inconsistent. Two meta-analyses point to a real but modest effect, with the certainty of evidence rated low to very low.
Scientific evidence
A 2018 meta-analysis of 10 studies found that taurine improved overall endurance performance by a small-to-moderate amount. Benefits were seen with doses from 1 to 6 g, and there was no difference between a single dose and up to two weeks of supplementation. [44]
In eight well-trained middle-distance runners, a single 1 g dose of taurine taken two hours before a 3 km time trial improved finishing time by 1.7% (10:46.6 versus 10:58.5), although the individual response ranged from slightly worse to about 4% better. [42]
In 11 healthy men cycling to exhaustion in the heat (35°C), 50 mg/kg of taurine (roughly 3.5 to 4 g) taken two hours before exercise increased time to exhaustion by 10% (25.2 versus 22.4 minutes), reduced post-exercise blood lactate by 16.5% and increased sweat rate, with a lower core temperature late in exercise. [40]
In 12 recreationally active men, the same 50 mg/kg dose increased critical power (the highest power output that can be sustained without fading quickly) from 193 W to 212 W, and extended time to exhaustion at a severe intensity from 16.0 to 17.7 minutes. [41]
A 2025 systematic review and meta-analysis of 23 randomized trials (308 participants) found a small-to-moderate improvement in overall exercise performance after a single dose of taurine. Benefits were most apparent for aerobic endurance, strength and power, and agility, while results for muscular endurance and anaerobic capacity were inconsistent. No dose-response relationship was found within the 1 to 6 g range, taking it about an hour before exercise looked most favourable, and the certainty of evidence was rated low to very low. [43]
Effective dose: 1 to 6 g
Most exercise studies used between 1 and 6 g. No clear dose-response relationship has been found, so larger doses do not appear to produce larger benefits.
Should taurine be in a pre-workout?
Yes, it is one of the better-justified Tier C ingredients. It works from a single dose taken an hour or two before exercise, the research range starts at 1 g, and it is inexpensive, so a pre-workout can include an effective amount without adding much bulk or cost. The benefit is modest and mostly shows up in endurance and repeated high-intensity efforts rather than in maximal strength, so treat it as a useful addition rather than a reason to choose one product over another.
D Tier D: Common In Pre-Workouts, Little Performance Evidence
Tier D contains ingredients that are commonly included in pre-workout or sports supplements but have limited, inconsistent or largely theoretical evidence for improving exercise performance. That does not mean they have no physiological role or no possible benefit in other contexts. It means the current evidence does not justify treating them as performance ingredients in a pre-workout.
L-Arginine
Function
L-arginine is the amino acid the body converts directly into nitric oxide, which widens blood vessels and increases blood flow to working muscle. It is the original "pump" ingredient and is still common in pre-workouts. The problem is delivery: a large share of oral arginine is broken down in the gut and liver before it reaches the bloodstream, which is why citrulline, which the kidneys convert to arginine, raises blood arginine more reliably.
Why is L-arginine Tier D?
Arginine has a real mechanism and a measurable effect on muscle blood flow, which is why it sits at the top of Tier D rather than lower. But the one meta-analysis that reported performance benefits has been credibly disputed for calculation errors, and the studies that test arginine the way a pre-workout is used, as a single dose before resistance training, have found no improvement in strength or repetitions. More blood flow without better performance is not a performance ingredient.
Scientific evidence
A 2020 systematic review and meta-analysis of 15 studies reported a significant benefit of arginine supplementation for both aerobic and anaerobic performance. However, the aerobic result came with very high heterogeneity (meaning the studies disagreed widely), and a 2025 published comment identified errors in the analysis, including three outlying studies whose results appear to have been miscalculated (standard errors used in place of standard deviations) and results from the same participants counted more than once. The comment concludes that correcting these errors would dramatically change the pooled estimate, so the headline finding should be treated with caution. [47] [48]
In resistance-trained men, a single 6 g dose of L-arginine before exercise did not improve bench press or isokinetic knee extension performance, and did not raise blood markers of nitric oxide production. [46]
In another randomized, double-blind study of 15 men, 6 g of L-arginine taken 80 minutes before exercise significantly increased muscle blood volume during the rest periods between sets of elbow extensions, but peak torque and total work were no different from placebo. The authors concluded it was premature to recommend arginine for strength. [45]
Effective dose: not established
Most exercise studies used around 6 g taken 60 to 90 minutes before exercise. No dose has been shown to reliably improve performance, and higher oral doses are limited by stomach upset.
Should L-arginine be in a pre-workout?
Only as a second choice to citrulline. The nitric oxide mechanism is sound, but citrulline achieves it more reliably because it survives digestion and has human performance data behind it. If a pre-workout contains both, the arginine is doing little that the citrulline isn't already doing.
BCAAs
Function
Branched-chain amino acids (BCAAs) are leucine, isoleucine and valine. They are essential amino acids involved in muscle protein metabolism, with leucine in particular playing an important role in triggering muscle protein synthesis.
Why are BCAAs Tier D?
BCAAs are physiologically important, but taking extra isolated BCAAs does not reliably improve strength, endurance or exercise performance, particularly when enough dietary protein is already being eaten. There is some evidence that BCAAs reduce muscle soreness after strenuous exercise, but this does not consistently translate into better performance in the following days.
Scientific evidence
A 2021 systematic review and meta-analysis of 25 studies (479 participants) found that BCAA supplementation reduced muscle soreness at 24 and 48 hours and lowered markers of muscle damage at 48 hours after strenuous exercise. However, it did not accelerate the recovery of muscle performance, which the authors describe as questionable. [49]
A 2022 systematic review of 24 studies in athletes and regularly training individuals concluded that although BCAAs tended to activate anabolic signalling and reduced soreness in resistance-trained participants, the benefits for performance and body composition were negligible. Most studies did not report total daily protein intake, so even the positive findings should be read with caution. [51]
A 2026 systematic review of BCAA and leucine supplementation in endurance athletes found no consistent improvement in performance, fatigue or recovery. Only two of the 15 included studies reported any significant difference, and the one reporting reduced soreness did not adequately control for protein intake. [50]
Effective dose: none established
There is no established dose of isolated BCAAs that reliably improves strength, power or endurance.
Should BCAAs be in a pre-workout?
Not for performance. If you are eating adequate protein, you are already getting more leucine, isoleucine and valine than any BCAA scoop provides. They add cost and sweetener load without a performance return. The one plausible use is a modest reduction in soreness after very hard sessions, which you also get from eating enough protein.
L-Glutamine
Function
Glutamine is the most abundant amino acid in the human body and is involved in nitrogen transport, immune function, intestinal health and cellular metabolism. Exercise can temporarily lower glutamine concentrations, which led to the suggestion that supplementation might improve recovery, immune function or performance.
Why is glutamine Tier D?
Despite its important physiological roles, glutamine supplementation has not consistently been shown to improve exercise performance in healthy athletes. Where it may have a role is in gut or immune health under specific circumstances, not in strength, power or endurance.
Scientific evidence
A systematic review of 47 studies, with 25 trials pooled in a meta-analysis, found that glutamine supplementation had no significant effect on aerobic performance or on most immune outcomes in athletes. The only body composition finding was a modest reduction in body weight; the authors' overall conclusion was that glutamine has no effect on immune function, aerobic performance or body composition. [52]
Effective dose: none established
There is no well-established glutamine dose that improves strength, power, muscular endurance or aerobic performance when used as a sports supplement.
Should glutamine be in a pre-workout?
No. It has no demonstrated performance effect and nothing about it depends on timing before exercise. The theory looked promising, but the trials since have not supported it.
Agmatine Sulfate
Function
Agmatine is produced naturally from the amino acid arginine and interacts with several biological pathways, including those involved in nitric oxide signalling and neurotransmission. It is commonly added to pre-workouts with claims about nitric oxide production, blood flow, muscle pump and performance.
Why is agmatine Tier D?
Agmatine is a clear example of an ingredient with an interesting theoretical mechanism and almost no meaningful human exercise evidence. Its popularity in pre-workouts is well ahead of the research.
Scientific evidence
There is no study we could find in which agmatine sulfate improved blood flow, strength, power, training adaptations or body composition in exercising humans. The research that exists is overwhelmingly in animals or isolated cells, and the small amount of human work has looked at potential medical uses rather than athletic performance. That absence is itself the finding: a pre-workout ingredient with no human performance trial behind it cannot be ranked any higher than Tier D.
Effective dose: none established
There is not enough human exercise research to establish an evidence-based performance dose for agmatine sulfate.
Should agmatine be in a pre-workout?
Not on current evidence. If a product lists agmatine as a reason to buy it, there is no human performance study to support that. Citrulline (Tier B) is the nitric oxide ingredient that actually has human performance data behind it.
B Vitamins
Function
B vitamins play essential roles in normal energy metabolism, red blood cell production, nervous-system function and the metabolism of carbohydrates, fats and proteins. Because of their role in energy metabolism, they are often included in pre-workouts and energy products and marketed as ingredients that provide "energy".
Why are B vitamins Tier D?
B vitamins are essential nutrients, but being required for energy metabolism does not mean that taking extra B vitamins before exercise produces extra energy or better performance. A deficiency can impair health and exercise capacity, so correcting one matters. That is a different thing from using high doses as an acute performance aid.
Scientific evidence
A review of B vitamins and exercise concluded that active people with poor or marginal B-vitamin status may have a reduced ability to exercise at high intensity, and that exercise may modestly raise requirements for riboflavin and vitamin B6. Its practical recommendation was that athletes with poor diets, particularly those restricting energy intake or cutting out food groups, should consider a multivitamin. It does not suggest that extra B vitamins improve performance in people who are already adequately nourished. [53]
Effective dose: no established performance dose
B vitamins should be consumed in amounts that meet nutritional requirements and correct any deficiency. There is no established acute dose that enhances exercise performance in people with adequate status.
Should B vitamins be in a pre-workout?
They do no harm at sensible amounts and are cheap, so their presence is not a problem. Read them as a nutritional top-up rather than a reason the product will make you feel energised. Any energy you feel from a pre-workout is the caffeine.
The Perfect Pre-Workout
So what should a good pre-workout actually contain?
Based on the research above, this is what I would look for. The key ingredients should be there at doses that actually match the research, while Tier C ingredients are more optional depending on what you want from the formula.
The doses below are the evidence-based ranges covered throughout this article.
Add up the A and B doses and you reach 12 to 17 g of active ingredients before anything from Tier C, and before flavouring or sweetener. That is the practical test. A scoop of 6 to 10 g cannot hold research doses of more than three or four of these, so when a product lists eight or more actives inside a 7 g serving, most of them are present in amounts that have never been shown to work.
This is not a theoretical problem. In our comparison of seven pre-workouts sold in Canada, four of the seven contained between 3.6 g and 7.3 g of active ingredients per serving in total. Only three cleared 12 g.
See the full pre-workout comparison
How Does Ignite Compare?
Ignite was formulated around the same evidence used throughout this guide. Here it is laid out the same way, with the dose per serving in each pill.
At 240 mg, the caffeine dose works out to approximately 3.4 mg/kg for a 70 kg person, comfortably within the evidence-based range. Beta-alanine is included at 3.2 g, while citrulline malate and betaine are included at research-backed doses. Taurine sits at the lower end of the studied range.
L-tyrosine is included at 1 g as part of the focus blend. As discussed above, this is below the doses used in many of the positive studies, so we do not treat it as a primary performance ingredient. Sodium is included primarily as an electrolyte to help replace what is lost through sweat.
What is not included matters too.
There is no creatine because, despite being a Tier A supplement, it is inexpensive, takes up considerable space in a formula and does not need to be consumed immediately before training. We think it makes more sense as a standalone daily supplement.
There is no nitrate because the strongest evidence generally involves taking a measured dose around 2 to 3 hours before exercise, which is better suited to a dedicated nitrate or beetroot product than a conventional pre-workout taken shortly before training.
There is also no agmatine, BCAAs, glutamine or added B vitamins simply to make the ingredient panel longer. Based on the evidence reviewed in this guide, they do not add enough to justify their inclusion.
In total, Ignite provides approximately 16 g of active ingredients per serving, with the majority coming from ingredients ranked in Tiers A and B. This level of evidence-based dosing is still fairly unusual in the pre-workout space, which is exactly why we designed Ignite this way.
The point of this article is not to ask you to take our word for it. Use the same criteria on Ignite that you would on any other pre-workout: check the ingredients, check the doses and compare them with the research. If another product passes the same test, it is a good pre-workout too.
Ingredients Not Covered
A few things turn up on pre-workout labels that are not ranked above, either because they sit outside the scope of a pre-workout or because there is too little to rank.
Sodium bicarbonate has good evidence as a buffer for efforts of one to seven minutes, in the same way as beta-alanine, but the effective dose (around 0.3 g per kg, or 20 g or more for most adults) and the stomach upset it causes mean it is almost never used in pre-workout powders.
Electrolytes such as sodium and potassium are included in some pre-workouts, including ours. They replace what is lost in sweat and support hydration, which matters for long or hot sessions, but they are not performance ingredients in the sense used in this article and are not tiered.
Pump ingredients such as glycerol, Nitrosigine (inositol-stabilised arginine silicate) and various plant extracts have a small number of mostly short-term studies behind them. They would sit in Tier C or D on current evidence.
Adaptogens such as rhodiola and ashwagandha appear in some newer formulas. The research is mixed and mostly concerns perceived fatigue or stress rather than measured performance, which would place them in Tier C or D.
Additional stimulants such as yohimbine, synephrine and various methylated compounds are common in high-stimulant products. The performance evidence is weak and some carry safety concerns, so they are deliberately left out of our formula and out of this ranking.
About the author
Joe is a certified trainer, strength and conditioning coach, and nutrition coach. He holds a Bachelor of Science with Honours in Sport and Exercise Science, graduating with First Class standing. During his studies, Joe focused on human physiology and performance, and he applies this knowledge of exercise science to his work with Thrive. Joe is the co-founder of Thrive Protein, a Canadian family-run supplement company focused on clean, scientifically backed nutrition products, including protein powders, greens, and electrolytes.
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