Caffeine peaks around 45–60 minutes in. Beta-alanine does nothing on the day you take it. Here is what each ingredient is actually doing, when to time it, and how to stop it wrecking your sleep.
Most people take pre-workout wrong in the same two ways: they drink it in the car on the way to the gym, and they take a full scoop because that is what the scoop is for. Then they are still wide awake at one in the morning wondering why.
Pre-workout is not one thing. It is three or four separate ingredients with completely different timelines — one works in an hour, one works over a month, and one may not do much at the dose it is usually included at. Knowing which is which is most of what you need.
What is actually in the tub
Caffeine — the one doing most of the work
If a pre-workout does anything noticeable for you, it is overwhelmingly this. The ISSN position stand on caffeine and exercise performance reports consistent benefits at 3–6 mg per kg of bodyweight, across muscular endurance, strength, sprinting, jumping and a broad range of sport-specific actions.
Note that the dose is per kilogram. Our Voltage Pre-Workout has 300 mg of caffeine in a scoop. For an 80 kg lifter that is 3.75 mg/kg — mid-range. For a 50 kg lifter it is 6 mg/kg, the top of the studied range, in a single hit. Same scoop, meaningfully different dose.
Beta-alanine — works, but not today
This is the one that is most widely misunderstood, and the tingling is why.
Beta-alanine raises muscle carnosine, which buffers the pH drop that comes with hard sets. The ISSN position stand on beta-alanine found that 4–6 g daily for at least 2–4 weeks raises carnosine enough to improve performance. That is a chronic loading effect, exactly like creatine.
So the tingle you feel twenty minutes after your scoop is not the beta-alanine working. It is paraesthesia, a harmless acute nerve response, and the position stand notes it can be reduced by splitting into doses of around 1.6 g. The performance effect is happening — or not happening — somewhere else entirely, over weeks.
The practical consequence is uncomfortable for the whole product category: if you take a pre-workout only on training days, three times a week, you are not getting an effective beta-alanine protocol. You would need it daily, rest days included. Ours has 3.2 g per scoop, which is a sensible single dose, but three doses a week is not the same as daily.
Citrulline — the pump ingredient, with a caveat
L-citrulline raises arginine availability and supports nitric oxide production, which is where the pump sensation comes from. The most-studied protocols use around 6–8 g of citrulline malate 30–60 minutes before training.
Ours contains 4 g. That is below the range most of the research uses, and worth saying plainly. It is also worth saying that the evidence here is genuinely mixed — several trials have found no performance benefit from acute citrulline at doses higher than ours. Pump is also largely a sensation rather than a performance outcome. Treat this ingredient as a nice-to-have, not the reason to buy.
The rest
L-tyrosine is included for focus under fatigue; the evidence is more promising for stress and sleep deprivation than for lifting specifically. Electrolytes support hydration, which matters more in an Indian summer than most formulas admit. Neither is a headline ingredient and neither should be sold as one.
Timing it properly
30–45 minutes, not five
Blood caffeine generally peaks 45–60 minutes after you drink it, and the ISSN stand notes 60 minutes pre-exercise as the most common timing in the research. The goal is for the peak to land on your heaviest working sets, not on your warm-up.
In practice: drink it 30–45 minutes before your first working set, accounting for your commute and your warm-up. If your session's hardest work is 40 minutes in, you can push toward the earlier end.
The sleep problem, which is the real cost
Caffeine's half-life is roughly five hours in most adults. That means about 150 mg of a 300 mg scoop is still in your system five hours later, and about 75 mg after ten.
In a 2013 trial published in the Journal of Clinical Sleep Medicine, Drake and colleagues gave subjects 400 mg of caffeine at 0, 3 and 6 hours before bed. Even the six-hour dose measurably disrupted sleep. It was a small study — twelve people — so hold the specifics loosely, but the direction is consistent with everything else known about caffeine pharmacology.
This matters because sleep is not a side issue for a lifter. It is where the adaptation you trained for actually happens. A pre-workout that adds 5% to tonight's session and takes 90 minutes off tonight's sleep is a bad trade, repeated three times a week.
Practical rule: nothing caffeinated within six hours of bed. If you train at 9pm, this product is not for you — train caffeine-free, or accept the cost knowingly.
Dosing to your bodyweight
Using the ISSN's 3–6 mg/kg range, here is roughly where a 300 mg scoop lands:
- 50 kg — full scoop is 6.0 mg/kg. Top of the range. Start with half.
- 60 kg — full scoop is 5.0 mg/kg. Upper-middle. Half a scoop is 2.5 mg/kg, just under the effective range.
- 70 kg — full scoop is 4.3 mg/kg. Comfortably mid-range.
- 85 kg — full scoop is 3.5 mg/kg. Lower-middle of the range.
Anyone new to stimulants should start at half a scoop regardless of bodyweight, and only move up if half genuinely is not enough. More caffeine is not more performance once you are inside the range — it is just more side effects and a longer tail into your sleep.
How to avoid the crash
"The crash" is usually one of three things, and only one of them is really about the supplement.
- A sugar drop. If your pre-workout is heavily sweetened or you took it with a sugary drink on an empty stomach, that dip is glycaemic, not caffeine.
- Caffeine landing on an existing sleep debt. Caffeine does not create alertness; it blocks the receptors that make you aware of your tiredness. When it clears, the tiredness you already had is still there and now has your full attention.
- Too high a dose. Overshooting brings jitteriness, a higher heart rate and a steeper subjective drop-off.
So: eat a proper meal one to two hours before training, take the smallest dose that works, drink water through the session, and do not use stimulants to cover for short sleep more than occasionally.
Who should skip pre-workout entirely
Be honest with yourself about this list. If you are pregnant or breastfeeding, have a heart condition or high blood pressure, are sensitive to stimulants, have an anxiety disorder that caffeine aggravates, are under 18, or train late in the evening — skip it, or speak to a doctor first. If you already drink three or four coffees a day, adding 300 mg on top is a bigger total than you probably think.
And if you are simply tired most days, the honest answer is that no scoop fixes that. Sleep, food and sane programming do.
Where pre-workout sits in the order of things
Pre-workout is a session-quality tool, not a foundation. Protein and creatine both do more for long-run results, cost less, and do not have a sleep cost. If you are building from scratch, get protein intake right first, then creatine — which, unlike beta-alanine in a pre-workout, is easy to take daily and has a much stronger evidence base. The creatine myths post covers why the usual objections do not hold up.
Then, if you still want help on the days you would rather stay on the sofa, a pre-workout is a reasonable purchase. Build Your First Supplement Stack puts the whole sequence in order.
Frequently asked questions
How long before a workout should I take pre-workout?
Around 30–45 minutes before your first working set. The ISSN position stand on caffeine notes 60 minutes pre-exercise as the most commonly used timing in research, and blood caffeine generally peaks 45–60 minutes after ingestion. Aim to have the caffeine peaking during your heaviest work, not during your warm-up.
How much caffeine should I take before training?
The ISSN position stand reports performance benefits at 3–6 mg per kg of bodyweight. For a 70 kg person that is 210–420 mg. A 300 mg scoop puts a 70 kg lifter at about 4.3 mg/kg, comfortably inside the range, but puts a 50 kg lifter at 6 mg/kg, right at the top of it. Dose to your bodyweight, not to the scoop.
Why does pre-workout make me tingle?
That is paraesthesia from beta-alanine, and it is harmless. It is also not a sign the product is working — the tingling is a acute nerve response, while beta-alanine only improves performance by raising muscle carnosine over weeks of daily use. Splitting into smaller doses of around 1.6 g reduces it.
Does beta-alanine in a pre-workout actually work?
Only if you take it every day, including days you do not train. The ISSN position stand found 4–6 g daily for at least 2–4 weeks raises muscle carnosine enough to improve performance. A single 3.2 g dose taken three times a week before training does not accumulate enough to do that job, whatever the tingling suggests.
How late is too late to take pre-workout?
Caffeine has a half-life of roughly five hours in most adults, so about half of a 300 mg dose is still circulating five hours later. A 2013 trial found 400 mg taken six hours before bed measurably disrupted sleep. Treat six hours before bedtime as the cutoff, and longer if you know you are caffeine sensitive.
How do I avoid the pre-workout crash?
Most of what people call a crash is either a sugar drop from a sweetened formula, caffeine wearing off on top of an existing sleep debt, or a dose higher than they need. Take the lowest dose that works, eat a real meal 1–2 hours before training, stay hydrated, and do not use pre-workout to paper over short sleep — that borrowing compounds.
Sources
- Guest NS, et al. International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr. 2021;18:1. PMC7777221
- Trexler ET, et al. International society of sports nutrition position stand: Beta-Alanine. J Int Soc Sports Nutr. 2015;12:30. PMID 26175657
- Drake C, Roehrs T, Shambroom J, Roth T. Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. J Clin Sleep Med. 2013;9(11):1195–1200. PMID 24235903
This article is general nutrition information, not medical advice. If you have a health condition, are pregnant or breastfeeding, or take prescription medication, speak to a doctor before using a stimulant supplement.