Quick answer
There is no official daily amount. Soreness trials used 5 to 29 g of BCAAs a day, and short muscle and strength studies about 10 to 14 g. NIH says up to 20 g a day, split into doses, appears safe, and a diet with enough protein already supplies 10 to 20 g a day.1,2,3
Key facts
- By body weight, the 18 trials in a 2024 analysis used about 0.08 to 0.54 g per kg a day.1
- The upper safe intake of leucine alone is put at about 500 mg per kg a day, from studies in men.2
- US men average about 100 g of protein a day and women about 69 g.2
- In the 2024 analysis, higher daily amounts went with larger drops in soreness the next day.1
The amounts used in studies
| What was studied | Daily amount | How long | What was found |
|---|---|---|---|
| Soreness after hard exercise, 18 trials pooled | About 3 to 29 g; 5 to 29 g in the soreness trials | 1 to 28 days | Lower soreness 24 to 96 hours later; NIH calls recovery evidence inconsistent |
| Muscle and strength during training | About 10 to 14 g | 3 to 6 weeks | Possible extra gains in a few short studies; inconsistent overall |
| Muscle protein building after lifting, 10 men | 5.6 g once | 4 hours | 22% above placebo, about half the response reported for whey |
| Women after menopause who lifted weights, 30 women | 9 g | 8 weeks | No added gain in muscle or strength |
The soreness trials varied widely. Some gave a single drink on the day of the hard session; others started days before it and carried on after. In the pooled data, higher daily amounts went with larger drops in soreness 24 hours later, and longer courses with larger drops in a muscle damage marker at 48 hours.1
By body weight
The trials that measured muscle soreness used 5 to 29 g of BCAAs a day. Across all 18 trials in a 2024 analysis, amounts ran from about 0.08 to 0.54 g per kg of body weight a day, taken for 1 to 28 days.1
For a person weighing 70 kg, 0.08 to 0.54 g per kg comes to about 6 to 38 g a day. The largest amounts, around 30 g a day, were given for a week or less, and they are above the 20 g a day that NIH describes as appearing safe. Read the per kg figures as a record of what was studied, not a target.1,2
One trial in young women set the amount at 0.1 g per kg, taken once before squats: about 6 g for a 60 kg woman.6
How much you already get from food
Complete proteins are about 25% BCAAs. If all of it came from complete protein, the average US man's 100 g a day would carry roughly 25 g of BCAAs and the average woman's 69 g about 17 g. NIH puts the usual range from a diet with enough protein at 10 to 20 g a day.2,3
Every 20 g of complete protein brings about 5 g of BCAAs along with the six other essential amino acids that a BCAA drink lacks. NIH notes that whey has more leucine than casein or soy.2
What 2:1:1 means for the dose
Most of the soreness trials pooled in 2024 used BCAAs in a 2:1:1 ratio: twice as much leucine as isoleucine or valine.1
So in a 4 g serving at 2:1:1, about 2 g is leucine and about 1 g each is isoleucine and valine. A 10 g serving in the same ratio holds about 5 g of leucine.1
What's in ours
What’s in ours
- BCAA 2:1:1: BCAA 2:1:1, 4,000 mg per serving, from the label
How much is too much
No tolerable upper intake level is set for BCAAs. NIH says up to 20 g a day, taken in divided doses, appears to be safe, and puts the upper safe intake of leucine alone at about 500 mg per kg of body weight a day, about 38 g for a 75 kg man, based on studies in men.2,3
NIH lists no known side effects and no safety concerns at 20 g a day or less for up to 6 weeks.2
Most safety data come from studies of a few weeks. A review of amino acid supplements notes that large amounts raise ammonia production and that the effects of high doses over the long term still need study.7
- Ask your doctor before any amount if you have liver disease, diabetes, ALS or another neurological condition, or are pregnant or nursing7,8
- If you take levodopa, ask your doctor or pharmacist first: amino acids compete with it for absorption9
- Under 18: NIH says that in most cases only adults should use performance supplements3
Questions people ask
How many grams of BCAA should I take a day?
No official amount exists. Trials that found less soreness used 5 g a day or more, the muscle studies about 10 to 14 g, and NIH says up to 20 g a day, split into doses, appears safe.1,2
Is 10 g of BCAA a day too much?
Not by the studies NIH reviewed, which reported no safety concerns at 20 g a day or less for up to 6 weeks. Longer use at high amounts is less studied.2
How much BCAA per day for muscle gain?
The short studies that hinted at extra muscle and strength used about 10 to 14 g a day for 3 to 6 weeks, but NIH calls the overall evidence inconsistent. Reaching your protein target with complete protein covers BCAAs as well.2
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Sources
- Salem A, et al. Attenuating Muscle Damage Biomarkers and Muscle Soreness After an Exercise-Induced Muscle Damage with Branched-Chain Amino Acid (BCAA) Supplementation: A Systematic Review and Meta-analysis with Meta-regression. Sports Med Open. 2024;10(1):42. Opened 2026-10-01.
- National Institutes of Health, Office of Dietary Supplements. Dietary Supplements for Exercise and Athletic Performance: Fact Sheet for Health Professionals. Updated April 1, 2024. Opened 2026-10-07.
- National Institutes of Health, Office of Dietary Supplements. Dietary Supplements for Exercise and Athletic Performance: Fact Sheet for Consumers. Updated March 22, 2021. Opened 2026-10-07.
- Jackman SR, et al. Branched-Chain Amino Acid Ingestion Stimulates Muscle Myofibrillar Protein Synthesis following Resistance Exercise in Humans. Front Physiol. 2017;8:390. Opened 2026-10-01.
- Bagheri R, Forbes SC, Candow DG, Wong A. Effects of branched-chain amino acid supplementation and resistance training in postmenopausal women. Exp Gerontol. 2021;144:111185. Opened 2026-10-07.
- Shimomura Y, et al. Branched-chain amino acid supplementation before squat exercise and delayed-onset muscle soreness. Int J Sport Nutr Exerc Metab. 2010;20(3):236-244. Opened 2026-10-07.
- Holeček M. Side effects of amino acid supplements. Physiol Res. 2022;71(1):29-45. Opened 2026-10-01.
- The Italian ALS Study Group. Branched-chain amino acids and amyotrophic lateral sclerosis: a treatment failure? Neurology. 1993;43(12):2466-2470. Opened 2026-10-07.
- Sinemet (carbidopa and levodopa) tablets: prescribing information (Organon). DailyMed, U.S. National Library of Medicine. Published August 24, 2026. Opened 2026-10-07.
This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.