The State of Supplement Underdosing 2026

We checked the 50 best-selling pre-workouts against published clinical dose ranges.

Standfirst

In June 2026, Proco transcribed the supplement-facts panels of the 50 best-selling pre-workout products on the US and UK markets and compared every disclosed dose against the clinical ranges published on Proco's ingredient pages — the dose ranges actually used in the human trials that underpin each ingredient's evidence base.

The headline result: 94% of the 50 products (47 of 50) either hide a key ingredient's dose inside a proprietary blend or disclose a key ingredient at a dose below the range used in clinical trials. The clearest single pattern is L-citrulline, the ingredient most products lead with on the front of the tub: of the 39 products that disclose a citrulline dose, 92% (36 of 39) fall below the 6,000 mg floor of the clinically studied range once citrulline malate is converted to its actual citrulline content.

Three products of the fifty met every applicable clinical floor with every dose disclosed.

Key findings

• 47 of 50 products (94%) either hide at least one key ingredient's dose in a proprietary blend or disclose at least one key ingredient below the clinical floor.
• 40 of 50 products (80%) disclose at least one key ingredient at a dose below the range used in clinical trials.
• 3 of 50 products (6%) disclose every dose and meet every applicable clinical floor.
• L-citrulline: 39 products disclose a dose; 36 of 39 (92%) sit below the 6,000 mg floor of Proco's published clinical range (6,000–8,000 mg).
• Beta-alanine: 40 products disclose a dose; 22 of 40 (55%) sit below the 3,200 mg floor of the clinical range (3,200–6,400 mg/day).
• Caffeine: 46 products disclose a dose; only 2 fall below the 150 mg floor of the clinical range (150–400 mg). Caffeine is the one ingredient in this dataset that is almost never underdosed.
• Creatine: 13 products disclose a creatine dose; 8 of 13 sit below the 3,000 mg floor of the clinical range (3,000–5,000 mg) — and several of those use creatine forms other than the monohydrate the trial literature is built on.
• 11 of 50 products (22%) use proprietary blends that conceal at least one ingredient's dose; 8 of those 11 hide the dose of at least one of the five key ingredients tracked in this report.

"Key ingredients" here means the five ingredients with the most established trial literature for pre-workout contexts, scored against Proco's published clinical ranges: L-citrulline, beta-alanine, creatine monohydrate, caffeine and L-theanine. A product is only scored on the ingredients its formula actually contains — a formula without creatine is not marked down for lacking it.

Why this happens: the economics of a scoop

The dataset shows a consistent asymmetry, and it tracks ingredient cost.

L-citrulline and beta-alanine are the expensive, high-mass ingredients in a pre-workout. A clinical citrulline dose is 6,000–8,000 mg — six to eight grams of a single ingredient, which on its own can exceed the entire scoop weight of some products in this sample (the smallest label serving in the dataset is 4.2 g). Beta-alanine's clinical floor is another 3,200 mg. These two ingredients dominate both the raw-material cost and the physical size of the serving.

Caffeine is the opposite: it is cheap, it is effective at milligram quantities rather than gram quantities, and its effects are immediately perceptible. A consumer can feel 200 mg of caffeine within half an hour; the same consumer cannot feel whether the citrulline in the scoop was 6,000 mg or 1,200 mg, because citrulline's measured effects in trials — on blood flow, training volume and soreness — are not acutely self-detectable in the way a stimulant is.

The numbers reflect this. In the 50 best-sellers:

• Caffeine: 2 of 46 disclosed doses below the clinical floor (4%).
• Beta-alanine: 22 of 40 below the floor (55%).
• L-citrulline: 36 of 39 below the floor (92%).

The pattern that emerges is descriptive, not conspiratorial: the ingredient that is cheap and feelable is dosed at or above clinical levels almost universally, while the ingredients that are expensive and not acutely feelable are the ones trimmed. A product can deliver a strong subjective experience — energy, tingling (beta-alanine produces paraesthesia at well below clinical doses), focus — while the doses responsible for the measured performance outcomes in the trial literature are partially or entirely absent.

The two products that do underdose caffeine are instructive exceptions: one is a low-stimulant formula positioned around a gentler profile (80 mg), the other discloses 145 mg, just under the floor. Neither resembles the citrulline pattern, where the median disclosed dose across the 36 below-floor products is roughly four grams against a six-gram floor.

The citrulline malate asterisk

The single most consequential mechanic in this dataset is a unit conversion that most labels do not explain.

Many products list "citrulline malate" rather than L-citrulline. Citrulline malate is citrulline bound to malic acid, usually at a 2:1 ratio by weight — meaning that of every gram of citrulline malate, only about two-thirds (0.667) is actually citrulline. The clinical range on Proco's L-citrulline page — 6,000–8,000 mg — refers to citrulline itself. So:

"6 g citrulline malate" is approximately 4 g of citrulline. A label can print a six-gram number while delivering four grams of the active ingredient.

Real examples from the dataset:

• REDCON1 Total War discloses 6,000 mg of citrulline malate 2:1 — approximately 4,000 mg citrulline, against a 6,000 mg clinical floor.
• Bucked Up Pre-Workout (original): the brand's marketing copy says "6g Citrulline", but the label itself reads 6 g citrulline malate 2:1 — again approximately 4,000 mg citrulline.
• Transparent Labs BULK discloses 8,000 mg of citrulline malate 2:1 — approximately 5,340 mg citrulline, just below the 6,000 mg floor despite an eight-gram headline figure.
• DY Nutrition Blood & Guts is the rare label that resolves the arithmetic itself: it states "L-Citrulline DL-Malate 2:1 = 6,004 mg, of which L-citrulline 4,340 mg". That disclosed 4,340 mg is the figure this report scored.

This conversion is why the citrulline picture looks worse than the raw label numbers suggest. Several products that print 6,000 mg or even 8,000 mg on the panel deliver 4,000–5,340 mg of citrulline. Where a label said "citrulline malate" without stating a ratio, this report assumed the standard 2:1 ratio and flagged the assumption (see Methodology). Trials of citrulline malate itself have typically used around 8,000 mg of the malate form — which, at 2:1, lands inside the citrulline range. Only a handful of products in the sample reach either figure.

Methodology

Sampling. The 50 products were selected from live bestseller signals captured on 5 June 2026: Amazon US Best Sellers (Pre-Workout Powders and the broader Pre-Workout node), GNC.com sorted by Top Sellers, Walmart.com sorted by Best Seller, Bodybuilding.com sorted by Best Selling, Amazon UK best-seller sort, and three credible 2026 editorial roundups (BarBend, Fortune, Men's Journal) for cross-checking. Amazon US sales rank was the primary ordering signal. Flavour and size variants were collapsed into one product line; single-ingredient powders and non-pre-workout items appearing in the category nodes were excluded. Amazon ranks #39–#50 could not be captured on the day (page load limit); the list bridges from #38 to #51, and no major product line is known to be missing in that gap, though it cannot be ruled out.

Label data. Every dose was transcribed from the product's official supplement-facts panel — the manufacturer's own label image or facts table, archived at the time of access (5–6 June 2026). Marketing copy was never used as a dose source: where a brand's marketing claims a figure that does not appear on the panel (for example, an off-panel caffeine claim), the dose was treated as undisclosed. Where a label has been reformulated, the current verified panel was used.

Serving basis. All doses are per single label serving, as directed on the panel. Several brands market a "full" two-scoop dose while the label's stated serving size and per-container count are based on one scoop; in those cases the one-scoop figures were used and the two-scoop marketing noted. Where the label's own serving size is genuinely two scoops, two-scoop figures were used.

Scoring. Doses were compared only against Proco's published clinical ranges — the dose ranges used in the human trials summarised on each ingredient page:

Citrulline malate was converted to citrulline equivalent at the stated ratio; where no ratio was stated, the standard 2:1 ratio was assumed and the assumption recorded. A disclosed dose below the floor of the range is recorded as below the clinical range. An ingredient absent from a formula is recorded as absent, not as a failure. An ingredient whose dose is concealed inside a proprietary blend is recorded as unverifiable — not as underdosed. In several blend cases the arithmetic constrains the possibilities (a 4,459 mg total blend cannot contain 3,200 mg of beta-alanine plus a clinical creatine dose plus its other listed ingredients), but this report scores only what the label states.

Limitations, stated plainly:

• Per-serving vs per-day for beta-alanine. Beta-alanine's evidence base rests on chronic daily loading (3,200–6,400 mg/day over weeks), not acute pre-workout dosing. A product delivering 1,600 mg per serving could reach the daily range if taken twice daily; this report scores the single directed serving, because that is how the label presents the product.
• Ratio assumptions. Six products list citrulline malate without a stated ratio; the 2:1 conversion applied to them is an assumption, flagged per product in the table. A different actual ratio would change those citrulline-equivalent figures.
• Partial-verification rows. Nine products carry acknowledged gaps and are marked † in the table: serving gram weights not printed in the captured sources (Legion Pulse, Bucked Up Woke AF, EVLution ENGN Shred, Genius Pre, Insane Labz Psychotic), a panel sourced from a third-party-published image of the current formula rather than an official numeric panel (C4 Ultimate), doses taken from an EU full-disclosure panel where the US label conceals some actives (C4 Ripped), headline actives captured without the full panel's gram weights (Applied Nutrition ABE), and a citrulline figure recorded from the brand's own stated split of a combined ingredient line rather than an itemised panel entry (Pre Lab Pro). Two of these rows (Genius Pre, ENGN Shred) additionally rely on older transcriptions because the current official pages no longer print doses. One further row, Optimum Nutrition Gold Standard, carried a beta-alanine source conflict — 1,500 mg in an older third-party transcription against 1,600 mg on the current official product page; the current official figure is used.
• Snapshot in time. Bestseller ranks are a 5 June 2026 snapshot and refresh frequently. Labels are as accessed 5–6 June 2026; formulas change, and several products in this sample were reformulated within the past two years.
• Forms. Creatine figures are scored against the monohydrate range regardless of form; three products use creatine nitrate, one creatine HCl and one a Kre-Alkalyn/chelate combination, forms with thinner trial literature than monohydrate. N-acetyl-L-tyrosine was recorded at the stated salt weight without conversion.

Full results: all 50 products

Key: ✓ disclosed at or above the clinical floor · ✗ disclosed below the floor (label mg shown vs floor) · ⊘ dose hidden in a proprietary blend · — not in the formula. Citrulline figures are citrulline equivalents after malate conversion; * marks an assumed 2:1 ratio; † marks a partial-verification row (see Methodology).

Notes on individual rows: #3 AminoLean's caffeine sits inside a 130 mg Energy and Focus Blend with a footnote stating no more than 125 mg per serving. #21 Nitraflex and #29 Bloom disclose caffeine but conceal the remaining tracked ingredients in proprietary complexes. #30 C4 Ultimate contains 1,500 mg creatine nitrate, a different compound from the monohydrate used in the trial literature; it is recorded but not scored against the monohydrate floor. #37 PMD discloses its headline actives within named sub-blends but conceals taurine and tyrosine doses; #39 C4 Ripped's US label conceals its fat-loss actives in a roughly 1 g blend (doses shown are from the EU full-disclosure panel); #40 ENGN Shred conceals betaine, tyrosine and alpha-GPC doses. These three carry proprietary blends without hiding any of the five key ingredients, which is why the blend count (11) exceeds the key-ingredient-hidden count (8). #41 Genius Pre is a deliberately caffeine-free formula; the absence of caffeine is recorded as absent, not underdosed.

The three products that met every applicable floor

Three of the fifty products disclose every dose on the panel and meet the clinical floor for every key ingredient their formula contains:

• GHOST Legend (V4) — 6,000 mg pure L-citrulline, 3,200 mg beta-alanine, 300 mg caffeine.
• Jocko Fuel Jocko Pre-Workout — 6,000 mg pure L-citrulline, 3,200 mg beta-alanine, 200 mg caffeine.
• Shifted Maximum Formula Pre-Workout — 8,000 mg pure L-citrulline, 3,200 mg beta-alanine, 5,000 mg creatine monohydrate, 325 mg caffeine, 150 mg L-theanine.

This is a statement about label disclosure and dose levels against published clinical ranges as of June 2026, not a product endorsement. Proco does not recommend products.

What the Proco Scanner does

This report is a manual, fifty-product version of what the Proco Scanner does automatically: it reads a supplement label, converts compound forms to their active equivalents (the citrulline malate arithmetic above is built in), flags doses hidden in proprietary blends as unverifiable, and compares every disclosed dose against the clinical ranges published on Proco's ingredient pages. Doses that actually work, not marketing claims.

The Scanner is currently in early access. Details at procohq.com.

Disclaimer and corrections

Proco provides educational, research-based information. This report describes what fifty product labels disclose and how those figures compare with published clinical dose ranges; it does not recommend, endorse or advise against any product or ingredient. Decisions about personal health belong with a qualified healthcare professional.