Caffeine, water, and a meal an hour or two beforehand. That covers the evidence for an ordinary session, and the reason it sounds unglamorous is that most of what the pre-workout category sells does not work the way it is sold.
The distinction the tubs never make is between ingredients that work the day you take them and ingredients that only work after weeks of daily loading. Most of a pre-workout scoop is the second kind, sold as the first.
The one ingredient that works acutely
Caffeine. The ISSN position stand supports 3–6mg per kilogram of body weight, about an hour before exercise — for a 70kg person, roughly 200–400mg. It improves endurance, strength-endurance and perceived effort in a single dose, and habitual use reduces the effect only "to a small degree."
There is newer evidence that lower doses do something too. A meta-analysis of resistance-exercise trials found measurable effects from roughly 0.9–2mg per kilogram — about 60–140mg, one to two cups of coffee — though the ISSN guidance still centres on the higher range, and this is a developing corner of the literature rather than a settled one.
For scale: a cup of brewed coffee is about 95mg. A commercial pre-workout averages 254mg, per a survey of the 100 best-selling products. The EFSA safety ceiling is 200mg in a single dose and 400mg across a day for healthy adults.
Caffeine's half-life is in the region of five to six hours. An evening session on a 300mg scoop is a sleep problem, and sleep is a bigger recovery input than anything in the scoop.
The ingredients that only work with daily loading
This is the part that changes how you read a label.
Creatine. The most effective ergogenic supplement there is — the ISSN position stand is unambiguous. It works by saturating a store in your muscle, which takes a loading phase (around 20g a day for a week, or 3g a day for a month) and then 3–5g a day to maintain. A single dose before a session does nothing measurable for that session. It is a daily supplement that happens to get packaged in pre-workout tubs. The survey above found it in only half of commercial products, at an average of 2.1g — below the maintenance dose.
Beta-alanine. Genuinely supported for hard efforts of one to four minutes — after two to four weeks at 4–6g a day. The ISSN position stand states directly that single large doses have not been effective for performance. The tingling you feel from a pre-workout is beta-alanine acting on skin receptors. It is harmless and it is not a sign the ingredient is "working" — the thing it does takes weeks. Commercial products average 2g, half the effective dose.
Citrulline malate. Studied as an acute dose, usually 8g. The best recent meta-analysis found a small effect at 8g that became non-significant once outliers were removed, and no benefit at 12g. Low certainty, and commercial products average 4g.
Taurine. The review in the sports nutrition literature says the findings are too limited and varied for definitive conclusions, with the most promising protocols spread across several days rather than one dose. It is in our formula, so we are not saying that to be unkind — what taurine actually does gets the full treatment.
BCAAs. Not supported as a standalone ergogenic or muscle-building aid. Wolfe's review sets out why: without the other essential amino acids, they cannot build muscle protein, and infusion studies found they reduced protein turnover. Dead weight in a pre-workout.
Beetroot and nitrates have a real literature behind them, mostly favouring multi-day loading over a single dose. We could not independently verify the quantitative claims to our standard for this article, so we are not going to quote a number.
What is actually in the tub
The survey of the top 100 pre-workouts is worth reading in full, because it is the category describing itself:
- Caffeine in 86% of products, averaging 254mg.
- Beta-alanine in 87%, averaging 2g — half the effective dose.
- Citrulline in 71%, averaging 4g — half the studied dose.
- Creatine in 49%, averaging 2.1g — below maintenance.
- 44% of all ingredients hidden inside proprietary blends with no disclosed amounts.
So the typical scoop is a real caffeine dose, plus sub-effective amounts of ingredients that would need daily loading anyway, plus a blend that does not tell you what is in it.
The category also has a history. The FDA declared DMAA an illegal ingredient after it showed up in pre-workouts, and later did the same for DMHA. Both were stimulants sold as "energy" that had no business in a supplement.
The input the category forgets: fluid
Pre-workout tubs are about stimulation. The evidence says the starting condition that most reliably costs you performance is a different one.
Starting a session meaningfully short on fluid measurably hurts you. A meta-analysis of aerobic performance found impairment of about 2.4%, with a threshold near 2–3% of body mass lost. Pooled data on strength and muscular endurance point the same way, with endurance hit harder. The full picture of when it matters and when water is enough is here.
There is even preliminary evidence that pre-loading fluid with sodium before a hot effort improves retention and, in a small trial, time-trial performance. Small sample, described by its authors as exploratory — but the direction is sodium-and-fluid, not stimulant.
So what do you actually need?
For an ordinary session — an hour, indoors, not in heat, not fasted:
- Caffeine, if you want it, dosed to your tolerance, about an hour out. Coffee is a pre-workout.
- Enough fluid that you are not starting 2% down.
- Food an hour or two before, so you are not running on fumes.
That is the evidence. It costs almost nothing.
A commercial pre-workout makes sense in one situation: you are already taking creatine and beta-alanine daily, you want them in one scoop with your caffeine, and you have checked the amounts are actually effective doses rather than the category average. Then it is a convenience. It is never a single-dose unlock, because the ingredients that would make it one do not work that way.
Frequently asked questions
What is the best pre-workout? For an ordinary session, caffeine dosed to your tolerance plus fluid plus food. Among commercial products, the best is one that discloses every amount and doses creatine and beta-alanine at levels that actually work — most do not.
Does pre-workout actually work? The caffeine does, acutely. Creatine and beta-alanine work after weeks of daily loading, not from a single scoop. Citrulline is marginal. BCAAs do nothing useful.
Is coffee a good pre-workout? Yes. A cup is about 95mg of caffeine, inside the range where measurable effects begin, an hour before training.
How much caffeine should I take before a workout? The ISSN supports 3–6mg per kilogram. Newer work finds effects from around 1mg per kilogram. EFSA's single-dose safety ceiling is 200mg. Start low; the effect does not scale forever and the sleep cost does.
What does the tingling from pre-workout mean? Beta-alanine acting on skin receptors. Harmless, and not a sign of anything working — beta-alanine's actual effect takes weeks of daily use.
Should I take pre-workout on an empty stomach? Caffeine hits faster on an empty stomach and can sit badly. Food an hour or two before is the better-evidenced input anyway.
Where Snake Oil fits
It is not a pre-workout in the tub sense, and we are not going to dress it up as one.
What it is: 100mg of caffeine — a cup of coffee's worth, disclosed, inside the range where lower-dose effects have been measured and comfortably under the single-dose safety ceiling — in a drink built around the input the category forgets. The fluid comes with 370mg of sodium and the 5g of carbohydrate that keeps it in you, and the potassium, magnesium, zinc, B vitamins, C, E and glutamine-led amino acids come along.†
For an ordinary session, that is the evidence-supported pre-workout: a moderate caffeine dose and arriving hydrated, in one glass. It will not load your creatine. Nothing in a single scoop does.
†These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Related reading: Electrolytes before or after a workout? · Theobromine vs caffeine