Does Betaine Actually Improve Strength and Power? What the RCTs Show
Educational summary — not medical advice. Betaine is not a proven strength-building supplement; sleep, progressive resistance training, and adequate protein intake move strength far more reliably. This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.
The honest answer
Some signal, mostly on secondary endpoints, never on 1RM strength itself. Seven sports-performance RCTs test betaine at ~2.5g/day. Several find real improvements in upper-body power, endurance reps, or body composition. But every single trial that measured 1-rep-max strength directly (Cholewa 2013, Cholewa 2018) found NO advantage for betaine over placebo — the primary strength outcome was null in both. One trial (Cholewa 2018) discloses a DuPont funding tie; disclosed here every time it's cited.
The seven trials, read together
| Study | Design | Result |
|---|---|---|
| Lee 2010 PMID 20642826 | Crossover, n=12 trained men, 14-day arms | Bench throw power & isometric bench press force up; jump squat power & rep performance no difference. Benefits "more apparent in smaller upper-body muscle groups." |
| Armstrong 2008 PMID 18438230 | Crossover, n=10 runners, hot-weather run+sprint | Sprint duration +16-21% but a nonsignificant trend; authors' own conclusion did NOT "definitively support" betaine for sprint performance. |
| Cholewa 2013 PMID 23967897 | RCT, n=23 strength-trained men, 6wk | Arm cross-sectional area, body fat%, lean mass improved; NO difference in bench press or back squat 1RM — the primary strength outcome was null. |
| Cholewa 2018 PMID 30064450 DuPont-funded | RCT, n=23 untrained collegiate women, 8wk | Body fat% and fat mass drop improved; squat 1RM improved ~equally in both groups — no strength advantage. One author employed by DuPont Nutrition & Health, a betaine supplier. |
| Hoffman 2009 PMID 19250531 | RCT, n=24 men, 15 days | Squat endurance (reps to exhaustion) improved at day 7 only; bench press endurance and every power/anaerobic measure (vertical jump, bench throw, Wingate) showed no difference. |
| Nobari 2021 PMID 33663545 | RCT, n=29 youth soccer players, 14wk, 2g/day | Testosterone:cortisol ratio increased; growth hormone, IGF-1, lean mass, body fat showed no significant interaction — an endocrine-marker shift, not a performance outcome. |
| Cholewa 2014 PMID 24760587 investigator review | Narrative review, not primary data | Concludes "positive effects... despite some conflicting results," while acknowledging mechanisms and long-term effects "remain to be elucidated." Author (Cholewa) ran two of the primary positive-leaning trials himself. |
Every trial that directly measured 1-rep-max strength (Cholewa 2013, Cholewa 2018) found no betaine advantage. Where positive results appear, they're on power, endurance-rep, or body-composition measures — real, but not the strength claim marketing often implies.
Why the signal clusters on secondary endpoints, not strength
Reading these seven trials together, a consistent pattern emerges: betaine's more plausible mechanism at ~2.5g/day is as an osmolyte that may support cell hydration and power output in acute efforts, or a modest influence on body composition over weeks of training — not a direct strength-building agent the way creatine's phosphocreatine-resynthesis mechanism is. Lee 2010's power gains were concentrated in "smaller upper-body muscle groups," a narrower finding than a general strength claim. Hoffman 2009's one positive measure (squat endurance) appeared only at a single timepoint (day 7) and not at day 14, undercutting a durable-effect story. And in both trials that directly tested the outcome people actually care about — how much weight can you lift for one rep — betaine matched placebo, not beat it.
The disclosed conflicts, named plainly
Cholewa et al. 2018 discloses that one study author was employed by DuPont Nutrition & Health, a betaine ingredient supplier — a real conflict of interest worth naming every time this trial is cited, including here. Separately, Cholewa 2014, the one narrative review synthesizing this literature, was authored by the same researcher (Cholewa) who ran two of the primary positive-leaning trials in this pack (2013, 2018). That doesn't make the review wrong, but it means it should be read as an investigator's own synthesis and perspective on his own body of work, not as an independent, disinterested meta-analysis — a distinction worth keeping in mind when you see this review cited as if it settled the question.
The one-line takeaway At ~2.5g/day, betaine shows some real signal on power, endurance reps, and body composition across small trials — but zero trials that measured 1-rep-max strength found an advantage over placebo. Honest verdict: some signal, mostly on secondary endpoints, never on 1RM strength itself. See the dosage guide for how this dose compares to the homocysteine range, and best betaine for the cheapest way to try it.
Compare Betaine (TMG) Products
If you're ready to buy, here's how the betaine (TMG) products we track and verify compare on cost per gram.
| Product | Dose/Serving | Servings | Price | Cost/Day | Certification | Buy |
|---|---|---|---|---|---|---|
| BulkSupplements Betaine Anhydrous Powder (1 kg) Best Value | 1500g betaine (TMG) | 666 | $28.97 | $0.07 | Third-party tested, cGMP | Buy on Amazon |
| Nutricost Betaine Anhydrous TMG Powder (500 g) | 1500g betaine (TMG) | 333 | $15.95 | $0.08 | 3rd-party tested (ISO lab) | Buy on Amazon |
| Vitamatic Betaine Anhydrous (TMG) Powder (250 g) | 1497g betaine (TMG) | 167 | $9.99 | $0.10 | None stated | Buy on Amazon |
| Nutricost TMG (Trimethylglycine) 750 mg (120 caps) | 750mg betaine (TMG) | 120 | $9.95 | $0.28 | 3rd-party tested (ISO lab) | Buy on Amazon |
| NOW Foods TMG Betaine 1,000 mg (Tablets) | 1000mg betaine (TMG) | 100 | $17.14 | $0.43 | cGMP (NPA-certified facility) | Buy on Amazon |
| Life Extension TMG 500 mg (100 Liquid Veg Caps) | 500mg betaine (TMG) | 100 | $19.95 | $1.00 | GMP; reputable manufacturer | Buy on Amazon |
Frequently asked questions
Does betaine build strength?
No trial found a 1RM advantage. Cholewa 2013 and 2018 both measured it directly and found no difference vs. placebo.
What did the positive trials actually find?
Upper-body power (Lee 2010), body composition (Cholewa 2013/2018), squat endurance at one timepoint (Hoffman 2009) — secondary endpoints, not strength.
Is there a conflict of interest?
Yes — Cholewa 2018 discloses a DuPont Nutrition & Health-employed author. Cholewa 2014's review was written by an author of two of the primary trials.
Should I take betaine for performance?
Possible small power/body-composition benefit at ~2.5g/day — not a strength-building supplement in the way creatine is.
Related
- Betaine (TMG): homocysteine and pre-workout, honestly explained
- Betaine dosage guide
- Best betaine — ranked by cost per gram
- Betaine and homocysteine
- Creatine — the pre-workout supplement with the actually-replicated strength evidence
- Beta-alanine — fellow pre-workout ingredient, its own honest-dosing story
Sources
- Lee EC, et al. "Ergogenic effects of betaine supplementation on strength and power performance." J Int Soc Sports Nutr. 2010. PMID: 20642826
- Armstrong LE, et al. "Influence of betaine consumption on strenuous running and sprinting in a hot environment." J Strength Cond Res. 2008. PMID: 18438230
- Cholewa JM, et al. "Effects of betaine on body composition, performance, and homocysteine thiolactone." J Int Soc Sports Nutr. 2013. PMID: 23967897
- Cholewa JM, et al. "The effects of chronic betaine supplementation on body composition and performance in collegiate females: a double-blind, randomized, placebo controlled trial." J Int Soc Sports Nutr. 2018. PMID: 30064450 (DuPont Nutrition & Health funding tie disclosed).
- Hoffman JR, et al. "Effect of betaine supplementation on power performance and fatigue." J Int Soc Sports Nutr. 2009. PMID: 19250531
- Nobari H, et al. "The effects of 14-week betaine supplementation on endocrine markers, body composition and anthropometrics in professional youth soccer players: a double blind, randomized, placebo-controlled trial." J Int Soc Sports Nutr. 2021. PMID: 33663545
- Cholewa JM, et al. "Effects of betaine on performance and body composition: a review of recent findings and potential mechanisms." Amino Acids. 2014. PMID: 24760587 (investigator-authored review, not an independent meta-analysis).