The short answer
- 11 of 52 best-selling pre-workouts reach the research dose on every key ingredient they list; 21 reach it on none.
- Creatine: 18 list it, 2 give the 3 g a day studies used.
- Beta-alanine: 47 list it; 19 give the 3.2 g a day studies used, 18 give less and 10 hide it.
- 16 of 52 (31%) hide at least one amount in a proprietary blend.
- Caffeine: the middle label has 200 mg a serving; 11 have 300 mg or more.
What we checked and how
The products. On 11 Oct 2026 we read Amazon.com's best-seller list for pre-workouts, ranks 1 to 100, by hand, set to a US delivery address. 45 of the 100 weren't multi-ingredient pre-workout powders (nitric-oxide capsules, beet root, single-ingredient creatine, citrulline or beta-alanine, a shaker bottle, a canned drink, a second flavour of a product already listed) and we left them out. That left 55 pre-workouts. We couldn't confirm the label of 3 of them, so they're not counted: Alpha Lion SuperHuman Core (sold on Amazon only; no brand label to read), Beyond Raw LIT V2 (we couldn't confirm our LIT label is the V2 formula) and MuscleTech Vapor X5 (the brand's site refused our connection). The other 52 are this study. The dated list of all 100 ranks, with the reason each one is in or out, is a download: the selection list (CSV).
The labels. One label per product: the newest one on the product's page here, so flavours of the same product count once. 40 come from the NIH Dietary Supplement Label Database and 12 from the brand's own facts panel; label dates run from 27 Jul 2021 to 11 Oct 2026. 12 of the 52 were also checked line by line by the editor. Data pulled 11 Oct 2026.
The verdicts. Each key ingredient (caffeine, citrulline, beta-alanine, creatine and betaine) is compared with the low end of the dose studies used, as in our methodology (version 1.11): one serving as printed, citrulline malate 2:1 counted as two-thirds citrulline, caffeine judged per kilogram at 75 kg. A product reaches "every key ingredient" when every key ingredient on its label reaches that dose. An amount hidden in a blend can't be confirmed, so it doesn't count as reaching it.
Citrulline
45 of the 52 list citrulline (87%). 27 give at least the 4 g studies used in one serving, 7 give less, 8 hide it in a blend, and 3 print citrulline malate without a ratio, so the citrulline in it can't be worked out. The middle disclosed amount is 4 g a serving; the range runs from 1.2 g to 8 g. Studies on citrulline used one dose before training, and the evidence for it is weak: the effects in studies are small.
On a label: "citrulline malate 2:1" is two parts citrulline to one part malic acid, so two-thirds of the printed weight is citrulline. "Citrulline malate" with no ratio doesn't tell you. See the citrulline guide.
Beta-alanine
Beta-alanine is the most common key ingredient: 47 of 52 list it (90%). 19 reach the 3.2 g a day studies used, 18 give less and 10 hide it. The middle disclosed amount is 3.2 g a serving (range 1.2 g to 4 g). Beta-alanine works through daily use over weeks, so a lower amount still builds up, just more slowly.
On a label: the tingling you feel isn't a dose check; the gram figure is. See the beta-alanine guide.
Creatine
18 of the 52 list creatine (35%), and only 2 give the 3 g a day studies used. 11 give less and 5 hide it. The middle disclosed amount is 1.5 g a serving (range 0.77 g to 5 g). Like beta-alanine, creatine builds up with daily use over weeks: a smaller daily amount still gets there, more slowly.
On a label: check the form. Creatine HCl is counted as the monohydrate it equals; see the creatine guide.
Betaine
18 list betaine (35%); every one of them discloses the amount. 9 reach the 2.5 g a day studies used and 9 give less. The middle amount is 2.25 g a serving.
On a label: look for "betaine anhydrous" (also sold as trimethylglycine). See the betaine guide.
Proprietary blends
16 of the 52 (31%) put at least one ingredient in a proprietary blend without its amount. Across all 670 ingredient lines on the 52 labels, 164 (24.5%) are inside a blend with no amount.
US labelling rules (21 CFR 101.36) let a blend show only its total weight, as long as its ingredients are listed from heaviest to lightest. So the first ingredient is at least the total divided by the number of ingredients, and no ingredient can weigh more than the total. That gives a range, not an amount. Example: Insane Labz Psycho Sam lists a 6603 mg blend of 8 ingredients with beta-alanine first. It holds somewhere from 825 mg to 6603 mg of beta-alanine, and studies used 3.2 g a day, so the label can't tell you which side of that it's on.
Caffeine and other stimulants
44 of the 52 list caffeine. 35 state the amount, 9 hide it in a blend, and 8 have none. Among those that state it, the middle label has 200 mg a serving, from 135 mg to 420 mg. 11 have 300 mg or more and 1 reaches 400 mg in one serving: that's the whole daily amount the FDA cites for most healthy adults. Performance studies used 225 mg to 450 mg for a 75 kg adult (3 to 6 mg per kg).
1 product lists a caffeine source (green tea, coffee bean or similar) without saying how much caffeine it adds. 13 (25%) list another stimulant as well: theacrine (TeaCrine) in 3, methylliberine (Dynamine) in 4, yohimbine / rauwolscine in 9 and synephrine (bitter orange) in 2. 16 also list theobromine, a milder relative of caffeine from cocoa.
On a label: add the caffeine from every line, then your coffee, with the free caffeine calculator. See the caffeine guide.
Taking more scoops doesn't fix it
7 products give less citrulline in a serving than the 4 g studies used. Matching that would take a median of 1.3 servings at once. For the 5 of them that state their caffeine, that many servings would also bring a median of 360 mg of caffeine, and 1 would pass 400 mg. This is label arithmetic, not a suggestion: the label's directions are what the product is sold for, and more scoops bring more of everything.
Stim-free pre-workouts
8 of the 52 are sold as stimulant-free. Here's the same count for them alone:
| Ingredient | List it | Research dose | Below | Hidden | Not graded |
|---|---|---|---|---|---|
| Citrulline | 8 of 8 | 6 | 1 | 0 | 1 |
| Beta-alanine | 5 of 8 | 4 | 1 | 0 | 0 |
| Creatine | 3 of 8 | 1 | 2 | 0 | 0 |
| Betaine | 4 of 8 | 3 | 1 | 0 | 0 |
Seven years after Jagim et al. (2019)
In 2019, Jagim, Harty and Camic published the ingredient profiles of the top 100 pre-workouts on bodybuilding.com, read in October 2018 (Nutrients 2019; 11(2):254). Their figures sit next to ours below. The samples and methods differ (a different store and year, their own inclusion rules, and averages of the amounts each label listed), so this is context, not a trend: two snapshots can't show the market got better or worse.
| Jagim et al. (2018 labels) | This study | |
|---|---|---|
| Ingredients per product (mean) | 18.4 | 12.9 |
| Of those, undisclosed in a blend (mean) | 8.1 | 3.2 |
| Products with at least one blend | 58% | 31% |
| Ingredients undisclosed in blends | 44.3% | 24.5% |
| Beta-alanine, mean listed | 2.0 g | 2.65 g |
| Citrulline, mean listed | 4.0 g | 4.44 g |
| Creatine, mean listed | 2.1 g | 1.94 g |
| Caffeine, mean listed | 254 mg | 233 mg |
Our means are per serving, of the amounts disclosed; citrulline malate 2:1 is counted as two-thirds citrulline. All amounts in this article are per serving, as printed: the amount the verdicts judge.
Limitations
- Label claims aren't lab results. We compare what the label says with what studies used. Whether the tub matches its label is a separate question; product pages show any published lab test.
- DSLD lags behind reformulations. A label can be a year or more old by the time it appears in the database. Each product page shows the label's date, and we use the brand's own panel where it's newer.
- The sample is a best-seller list, not market share. Amazon's ranking is one store on one day, it changes hourly, and it doesn't tell you how many tubs each product sells.
- Reference doses come from studies of specific people. Mostly healthy, trained adults; the doses may not carry over to everyone. Caffeine is judged at 75 kg.
The data
Download the data: pre-workout-label-study-2026.csv (CSV, one row per product, no prices). It's free to use under CC BY 4.0 with credit. Cite it as: Is It Underdosed? (2026). Pre-workout label study 2026. isitunderdosed.com/research/pre-workout-label-study-2026/
Ingredient guides: Caffeine · L-citrulline · Beta-alanine · Creatine · Betaine.
All 52 products
In Amazon best-seller order on 11 Oct 2026. Each links to its full label check.
Is It Underdosed? compares label amounts with published research doses. Nothing here is medical advice.