Pre-Workout Formulation Science: Clinical Dosages of Caffeine, Citrulline, and Beta-Alanine

A good pre-workout formula comes down to one proven ingredient and a few modest ones. Caffeine at 3-6 mg/kg, citrulline malate at 6-8 g and beta-alanine at 4-6 g a day are the doses that research has actually tested, and the effects are small. Tyrosine and alpha-GPC are optional extras at best.

This guide audits pre-workout formulation against clinical dosages so you can read a label, spot underdosing and decide whether to buy or mix your own. It sits inside our wider guide to creatine, protein powders and caffeine.

One honest caveat first. None of this is a substitute for sleep, food and a plan you can repeat. A pre-workout is a small edge, and nothing here is medical advice.

What does a pre-workout formula actually need?

Think of a formula as a short list with a dose and a timing attached to each line. If an ingredient has no tested dose, you are paying for hope.

A review of multi-ingredient pre-workouts describes the typical blend as caffeine, creatine, beta-alanine, amino acids and nitric oxide agents (Harty et al., 2018). The same review found that acute use may help muscular endurance and mood, with mixed results for force and power.

So the realistic promise is a bit more energy and maybe a rep or two. Not a transformation.

Creatine is the odd one out. It has strong evidence for high-intensity performance and training adaptations (Kreider et al., 2017), but like beta-alanine it works by building up in muscle with daily use, so timing it before a session is not the point. See creatine timing, pre vs post workout.

Caffeine: the ingredient doing most of the work

If a pre-workout feels powerful, it is probably the caffeine. The ISSN position stand says caffeine has consistently improved performance at 3-6 mg/kg body mass, and that minimal effective doses may be as low as 2 mg/kg (Guest et al., 2021). Very high doses, such as 9 mg/kg, bring a high rate of side effects without being needed for a benefit.

For strength specifically, a meta-analysis found caffeine improved 1RM strength (SMD 0.20) and power (SMD 0.17), with a significant effect for upper body but not lower body strength (Grgic et al., 2018). Those are small numbers.

Here is the arithmetic, using the ISSN range and the lower 2 mg/kg figure:

Body weight	About 2 mg/kg	3-6 mg/kg range
60 kg	120 mg	180-360 mg
70 kg	140 mg	210-420 mg
80 kg	160 mg	240-480 mg
90 kg	180 mg	270-540 mg

Check the caffeine figure on your scoop against this table. Start near the low end: a large systematic review concluded that up to 400 mg a day from all sources is generally not linked to overt adverse effects in healthy adults, and up to 300 mg a day in healthy pregnant women (Wikoff et al., 2017). The top of the 3-6 mg/kg range goes past that for heavier lifters, so count your coffee and chai too. “Inside the range” is not the same as “best for you”. Our caffeine dosage calculator does the sums for your weight.

Timing: the position stand says 60 minutes before exercise is the most common approach, and that gums may need a shorter wait. Habitual intake and genetics affect how you respond, so there is real person-to-person variation. One disclosure worth knowing: several position stand authors, and the ISSN itself, report funding or advisory ties to supplement companies. We look at the dose in more depth in caffeine dosing for strength and power and at powder versus coffee in caffeine anhydrous vs natural caffeine.

Citrulline: what does 6-8 g actually do?

Citrulline is the “pump” ingredient. The theory is that it raises nitric oxide and blood flow, though researchers also discuss ammonia handling and the malate part of citrulline malate.

The best direct evidence is a meta-analysis of 8 studies and 137 participants, mostly strength-trained. Taking 6-8 g of citrulline malate 40-60 minutes before training increased repetitions by about 3 (6.4%) compared with placebo, with a small effect size of 0.196 (Varvik et al., 2021). The upper body effect alone was not significant.

A separate meta-analysis of 12 studies on strength and power found a small pooled effect (0.20), with confidence intervals for every single study crossing zero (Trexler et al., 2019). The authors suggest it could matter to high-level athletes where margins are thin.

So: a small plausible benefit in repetitions, mixed elsewhere. If you want the pump angle without stimulants, see non-stimulant pump pre-workouts.

Beta-alanine: a daily habit, not a pre-workout trick

Beta-alanine is the ingredient people misuse most. It raises carnosine in muscle over weeks, and carnosine helps buffer acid. It does not work as a one-off hit before your session.

The ISSN position stand says 4-6 g a day for at least 2-4 weeks improves exercise performance, with larger effects in tasks lasting 1-4 minutes (Trexler et al., 2015). The only reported side effect is tingling (paraesthesia), which can be reduced with divided lower doses (1.6 g) or a sustained-release form. The same document says more research is needed on strength outcomes.

A larger meta-analysis of 40 studies and 1,461 people found an overall effect of 0.18, with exercise duration moderating the result (Saunders et al., 2017). Within 0.5-10 minute efforts, the benefit was clearer for exercise capacity than for performance.

What does that mean for a lifter? A heavy set of 5 lasts under 30 seconds, which is not where beta-alanine shines. It may help higher-rep sets, conditioning and repeated hard efforts. Be realistic about that.

Tyrosine and alpha-GPC: the “focus” lines

These two appear on labels to sell focus, but the lifting evidence is weak.

On tyrosine, a review concluded that its potential for enhancing physical exercise seems minimal, while it appears to help cognition in short-term stressful or demanding situations when dopamine or noradrenaline is temporarily depleted (Jongkees et al., 2015). A normal training session is rarely that situation. More in our L-tyrosine breakdown.

On alpha-GPC, a small crossover trial of 13 young men gave 600 mg a day for 6 days. Mid-thigh pull peak force rose by about 99 N compared with a 39 N drop on placebo, while the upper body test did not reach significance (Bellar et al., 2015). It is one small study. See alpha-GPC and nootropics for more.

If a product leans on these for its price, you are paying for the weakest evidence on the label.

Pre-workout label audit: a quick checklist

Use this before you buy. It takes two minutes.

• Is every ingredient listed with its amount in mg or g?
• Is caffeine per serving written clearly, and does it fit your weight?
• Does it say citrulline malate or L-citrulline, and is the dose near 6-8 g?
• If beta-alanine is present, is a day’s total close to 4-6 g across the day?
• Are tyrosine and alpha-GPC priced like extras, or like the main event?
• Is there a proprietary blend hiding amounts?
• Is there third-party testing?

Proprietary blends are the biggest red flag, because they hide the numbers you need. The review of multi-ingredient products says they make comparisons between formulations “challenging and often impossible” (Harty et al., 2018). Our guides on decoding proprietary blends and spotting them on a label go deeper.

Can you build your own pre-workout at home?

You can, and it is often cheaper per serving, but compare actual prices rather than trusting a headline figure. The evidence-backed ingredients are sold as single powders, which makes a DIY version simple on paper.

A sensible home formula looks like this:

1. Caffeine: dose it from your body weight, from coffee, tablets or a precise measure.
2. Citrulline malate: roughly 6-8 g, if you want to test it.
3. Beta-alanine: handled separately, daily, in split doses.
4. Optional extras: only if you have a reason.

Two practical cautions. First, caffeine powder is easy to overdose because a tiny weighing error becomes a large dose error, so without a precise scale use tablets or coffee instead. Second, buy from brands that publish third-party tests, since the review above notes that products can contain banned substances or contaminants.

In India, a strong filter coffee or a black coffee before training covers the caffeine step cheaply. Add citrulline malate in water if you want it. In a hot climate, drink water with it and avoid a big caffeine dose on an empty stomach if that upsets you.

Who should skip pre-workout?

Talk to a doctor before using high-caffeine products if you have a heart rhythm problem, high blood pressure, anxiety, or are pregnant. Skip evening use if it wrecks your sleep, because lost sleep costs more than the supplement gives.

Safety studies on multi-ingredient products are mostly short, under about 8 weeks, so long-term data are limited (Harty et al., 2018). For side effects and fixes, see pre-workout jitters, cramps and palpitations. For when to take each supplement across the day, see our daily supplement schedule.

The bottom line

Caffeine does the heavy lifting. Citrulline malate and beta-alanine add small, plausible edges at the doses studied. Tyrosine and alpha-GPC are optional. Before you buy, check that every dose is on the label and compare it with the research. Then spend the savings on food. If you need a training plan to go with it, start with our free push pull legs plan.