Home / Field guides / Clinical Doses: What the Research Actually Used
Field guide
Clinical Doses: What the Research Actually Used
Every ingredient on a supplement label is a dose decision, and most labels don't tell you what that decision was measured against. Below are the thresholds behind the pre-workout ratings, drawn directly from the studies that established them, along with what the research actually looked like and why "more" isn't automatically "better."
The thresholds
These ten are the pre-workout actives. The full set — every threshold used anywhere on the site, and every ingredient that is recognised but deliberately left unscored because no research establishes a dose for it — is published on how we rate.
| Ingredient | Clinical dose | Source |
|---|---|---|
| L-Citrulline | 6,000 mg | Bailey et al., J Appl Physiol 2015 |
| Citrulline Malate 2:1 | 8,000 mg | Perez-Guisado & Jakeman, J Strength Cond Res 2010 |
| Beta-Alanine | 3,200 mg | Trexler et al., ISSN Position Stand 2015 |
| Creatine Monohydrate | 5,000 mg | Kreider et al., ISSN Position Stand 2017 |
| Betaine Anhydrous | 2,500 mg | Cholewa et al., J Int Soc Sports Nutr 2013 |
| Caffeine | 200 mg | Guest et al., ISSN Position Stand 2021 |
| L-Tyrosine | 1,000 mg | Jongkees et al., J Psychiatr Res 2015 |
| Taurine | 1,000 mg | Waldron et al., Sports Med 2018 |
| Alpha-GPC | 300 mg | Ziegenfuss et al., J Int Soc Sports Nutr 2008 |
| L-Theanine | 100 mg | Giesbrecht et al., Nutr Neurosci 2010 |
These are the numbers a pre-workout is scored against. Not a marketing claim, not a round number that sounds sufficient — the dose that was actually administered in the study behind each ingredient's use case.
A threshold is only applied where the research that produced it was measured. Some are scoped to a single shelf for that reason: leucine's range is stated for an acute protein dose alongside a balanced array of the essential amino acids, so it is audited on the amino rankings rather than against a pre-workout that happens to contain leucine. Citing a trial at a product it was not measured on would be a wrong number wearing a citation.
Citrulline malate and L-citrulline are not the same ingredient
This is the single most common source of confusion on a pre-workout label, and it's worth being precise about it.
L-citrulline is the free amino acid on its own. Citrulline malate is L-citrulline bound to malate, typically in a 2:1 ratio, meaning a given weight of citrulline malate contains meaningfully less actual citrulline than the same weight of pure L-citrulline — the malate portion adds mass without adding citrulline.
Bailey et al. (2015) studied 6 g of L-citrulline. Perez-Guisado & Jakeman (2010) studied 8 g of citrulline malate. Those are different compounds studied at different total weights, and treating "8 g citrulline malate" as equivalent to or better than "6 g L-citrulline" misreads the label. A product listing "citrulline malate 8,000 mg" is not delivering 8 g of citrulline — depending on the exact ratio used, the actual citrulline content is lower, closer to 5–6 g minus the malate weight — and it isn't automatically equivalent to a product listing "L-citrulline 6,000 mg," which delivers a full 6 g of the amino acid itself.
This is why the two are tracked as separate line items rather than folded into one "citrulline" bucket. Conflating them would mean crediting a product for a dose it didn't actually deliver, which defeats the purpose of dose auditing in the first place.
Why exceeding a dose isn't a bonus
It's intuitive to assume that if 3,200 mg of beta-alanine is the studied maintenance dose, then 6,000 mg must work even better. That intuition doesn't hold up, and it isn't how we score.
The clinical dose is the amount the cited research used — a floor a label either reaches or doesn't, not a point on a scale where more is proportionally better. Above the studied range there is simply no data: the research measured what it measured at the doses it used, and going past them means you're outside the figures the "clinical dose" label was borrowing credibility from. A product that doses far above the threshold hasn't demonstrated anything more — it has demonstrated it's outside the range anyone actually measured. That is why this site credits a dose up to the threshold and no further.
Practically, this also means a giant dose isn't a substitute for an honest label. A product could bury an ingredient at 20,000 mg specifically to make the "clinically dosed" claim viscerally impressive while the total serving becomes unpalatable, expensive, or oddly proportioned relative to everything else in the formula. Meeting the threshold is the bar. It isn't a race past it.
What this means for reading a label
The useful exercise is narrow: find the ingredient, find its disclosed dose, and compare it against the number the research actually used — not a rounder number, not a related-sounding compound, not an assumption based on where it sits in the ingredient list. Where a dose isn't disclosed at all, because it sits inside a proprietary blend, there's no way to run this comparison, which is exactly why blends carry their own separate scrutiny.
This isn't dosing advice — what to take, and how much, is a decision between a reader and whoever they get personal guidance from. It's a description of what a specific set of studies used, so a label claim can be checked against something real.
Why these particular studies
The sources above aren't an arbitrary pick from the literature. Several are ISSN (International Society of Sports Nutrition) Position Stands — consensus documents where a panel of researchers reviews the available trials on an ingredient and states the doses those trials used. Where a single trial is cited instead of a position stand, it's because that trial established the dose most commonly referenced by later research on the same ingredient. None of this makes the number permanent — sports nutrition research continues, and a threshold can move if better evidence arrives — but it does mean each figure traces back to a published, citable source rather than to convention or round numbers that simply sound sufficient.
A caffeine range worth noting
Caffeine is the one ingredient on this list most often dosed by body weight in the underlying research rather than as a single fixed number — Guest et al. describe research doses of around 3–6 mg per kilogram of body weight, and 200 mg is used here as a fixed floor because a label states milligrams, not milligrams per kilogram. A product listing well below that floor is dosing under the range the position stand describes; a product dosing well above it is past the range the position stand describes, and this site does not credit the difference.