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Muscle & Recovery

L-Valine

Evidence Level
Preliminary
2 Clinical Trials
5 Documented Benefits
1/5 Evidence Score

L-Valine is an essential branched-chain amino acid (BCAA) along with leucine and isoleucine. Required for muscle metabolism, tissue repair, energy production, and nitrogen balance. Found in meat, dairy, soy, mushrooms, peanuts, whole grains. Like isoleucine, standalone valine supplementation is uncommon: most use is via BCAA blends (2:1:1 ratio with leucine and isoleucine) or complete protein sources. No published trial has given valine on its own and measured strength, muscle size, endurance or soreness. Dietary protein supplies valine well above the requirement, so deficiency is essentially unknown in anyone eating enough protein.

Studied Dose Valine on its own has not been tested for any exercise, muscle or recovery outcome; RDA 24 mg/kg/day, about 1.7 g/day for a 70 kg adult, which diet usually supplies.
Active Compound L-Valine (free amino acid)

Benefits

Building Block for Muscle Protein (Adequacy, Not Extra)

Valine is one of the nine indispensable amino acids the body must have to build muscle protein, so adequate intake is necessary. That is not the same as extra valine helping. Every human measurement comes from BCAA blends, in which leucine is the component that drives the response, and a 2024 review of the human data concluded that BCAAs stimulate muscle protein synthesis less than a complete protein providing all nine indispensable amino acids. Valine on its own has never been tested.

Supported by Trial 1, Trial 2

Oxidized for Fuel in Muscle (Biochemistry, Not a Measured Performance Effect)

BCAAs including valine are oxidized in skeletal muscle during prolonged exercise, and valine's carbon skeleton enters the TCA cycle as succinyl-CoA. That is established biochemistry. It has not been shown to translate into better endurance, spared glycogen or less fatigue in any trial of valine by itself, because no such trial has been published.

Supported by Trial 1

Requirement and Nitrogen Balance

Human tracer studies put the average adult valine requirement at about 17 mg/kg/day; the US RDA is 24 mg/kg/day once a safety margin is added, and the WHO/FAO/UNU average requirement is 26 mg/kg/day. Below the requirement, whole-body protein balance falls off. That establishes a requirement, and ordinary food protein meets it several times over. No trial has tested supplemental valine on wound healing, surgical recovery or any catabolic illness.

Supported by Trial 2

Competes With Tryptophan at the Blood-Brain Barrier (No Human Outcome Tested)

Valine shares the LAT1 transporter with tryptophan, tyrosine and phenylalanine, so a large isolated dose can reduce their entry into the brain. In rats, pre-exercise L-valine blocked the exercise-induced rise in hippocampal serotonin. No human study has measured whether valine changes mood, cognition or perceived fatigue. The same transport competition is why valine can blunt levodopa, so this mechanism is at least as much a caution as a benefit.

Supported by Trial 2, Trial 1

Glucogenic Energy Substrate

Valine is purely glucogenic (converts to succinyl-CoA → glucose), unlike leucine (purely ketogenic) or isoleucine (both). Provides glucose during fasting or prolonged exercise.

Supported by Trial 2, Trial 1

Mechanism of action

1

BCAA Metabolism

Valine shares BCAT and BCKDH enzymes with leucine and isoleucine. Maple syrup urine disease (MSUD) results from BCKDH deficiency, accumulating BCAAs and their α-ketoacids — toxic without dietary restriction.

2

mTORC1 Co-Activation

Valine contributes to amino acid sensing pathways activating mTORC1, though less potently than leucine.

3

Glucogenic Pathway

Valine is purely glucogenic — degrades to propionyl-CoA → methylmalonyl-CoA → succinyl-CoA, entering TCA cycle for glucose synthesis. Vitamin B12 is required cofactor for the methylmalonyl-CoA mutase step.

4

Nitrogen Balance

Essential amino acid — required for positive nitrogen balance and protein turnover.

Clinical trials

1
Meta-Analysis of BCAA Blends, Not Valine Alone: Muscle Damage and Soreness
PubMed

Systematic review and meta-analysis of 18 randomized controlled trials of branched-chain amino acid blends taken around exercise-induced muscle damage. Salem A and colleagues, Sports Medicine Open, 2024. No included arm gave valine on its own.

Healthy active adults performing resistance or endurance exercise. Thirteen of the 18 included trials were rated high quality and five acceptable.

BCAA blends lowered creatine kinase immediately after exercise (Hedges g -0.44, p = 0.006) and at 72 hours (g -0.99, p = 0.002) but not at 24, 48 or 96 hours, and lowered muscle soreness at 24 hours (g -1.34), 48 hours (g -1.75), 72 hours (g -1.82) and 96 hours (g -0.82) but not immediately. Lactate dehydrogenase did not change at any time point. Soreness and blood markers were the outcomes, not endurance performance, and the supplement was a leucine-dominant blend, so none of this can be credited to valine.

2
NOT A TRIAL: Rare-Disease Reference Chapter on Maple Syrup Urine Disease
PubMed

GeneReviews disease chapter by Strauss KA, Puffenberger EG and Carson VJ, last updated 23 April 2020. It is a clinical reference monograph on an inherited enzyme defect, not a study, and it reports no trial of valine supplementation.

Infants and adults with maple syrup urine disease, an inherited branched-chain ketoacid dehydrogenase defect. None of it applies to a healthy person considering a supplement.

In maple syrup urine disease, total dietary protein is restricted and leucine is titrated to tolerance, while valine and isoleucine are deliberately added back and monitored on plasma amino acid levels. The chapter states that continuous valine fortification is directly related to long-term intellectual outcome. That is a prescription regimen run by a metabolic team against blood levels in people who cannot break these amino acids down. It is not a reason for anyone else to take valine, and it says nothing about whether valine helps a healthy person.

Side effects and drug interactions

Common Potential side effects

Generally well-tolerated as part of BCAA blends.
GI distress at very high doses is uncommon. A large isolated dose of one large neutral amino acid competes with tryptophan, tyrosine and phenylalanine for the same blood-brain-barrier transporter, which is the mechanism behind the levodopa interaction below. Separately, people with higher circulating BCAA levels are more likely to have insulin resistance and to develop type 2 diabetes. Reviewers of that literature note the direction of cause is unsettled: insulin resistance can itself raise blood amino acid levels, and the proposed mechanisms point to leucine and to BCAA breakdown intermediates rather than to valine.
Consumer supplement sources list a crawling skin sensation and hallucinations after very large doses, but no published case report or trial documents either. No Tolerable Upper Intake Level has been set for valine: a 2023 review that established upper intake levels or no-adverse-effect levels for ten amino acids, including leucine, did not cover valine, so the safe ceiling for isolated valine is not known.

Important Drug interactions

Levodopa — BCAAs including valine compete for blood-brain barrier transport; reduce levodopa efficacy in Parkinson's; separate by 30–60 min.
Maple syrup urine disease (MSUD): total dietary protein and leucine are restricted, while valine and isoleucine are dosed by a metabolic team against plasma amino acid levels. Never self-supplement valine if you have MSUD; the amount is prescribed and monitored, and getting it wrong in either direction causes harm.
Diabetes medications — theoretical effects on glucose; monitor.

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Frequently asked questions about L-Valine

What is L-valine?

L-valine is an essential branched-chain amino acid (BCAA), one of the three (with leucine and isoleucine) named for their branched side chain. It is a building block of every muscle protein, so the body must get it from food. It is not a proven exercise supplement on its own.

What is L-valine used for?

Valine is required to build body protein, and food protein supplies it well above the requirement. Beyond meeting that requirement, nothing has been demonstrated: no trial has given valine by itself and measured strength, muscle size, endurance or soreness. It is usually obtained from protein or BCAA blends rather than taken alone, since the three BCAAs work together.

How much L-valine should I take?

Valine is typically consumed as part of a BCAA blend (often a 2:1:1 leucine-isoleucine-valine ratio) or from dietary protein, rather than dosed alone. Whole protein generally provides plenty.

Is L-valine safe?

It is generally safe as part of normal protein intake or BCAA supplements. People with the rare inherited condition maple syrup urine disease must not self-supplement: their protein and leucine intake is restricted while valine and isoleucine are dosed and monitored by a metabolic specialist. For most, whole-protein foods make isolated valine unnecessary.

What is the recommended dosage of L-Valine?

The clinically studied dose is Valine on its own has not been tested for any exercise, muscle or recovery outcome; RDA 24 mg/kg/day, about 1.7 g/day for a 70 kg adult, which diet usually supplies. Always follow the product label and check with a healthcare provider for personal advice.

Is L-Valine safe, and does it have side effects?

For most healthy adults, L-Valine is well tolerated at studied doses. Reported effects can include: Generally well-tolerated as part of BCAA blends. GI distress at very high doses is uncommon. A large isolated dose of one large neutral amino acid competes with tryptophan, tyrosine and phenylalanine for the same blood-brain-barrier transporter, which is the mechanism behind the… It may also interact with some medications. L-Valine is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does L-Valine interact with any medications?

Possible interactions include: Levodopa — BCAAs including valine compete for blood-brain barrier transport; reduce levodopa efficacy in Parkinson's; separate by 30–60 min. Maple syrup urine disease (MSUD): total dietary protein and leucine are restricted, while valine and isoleucine are dosed by a metabolic te… If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for L-Valine?

NutraSmarts rates the evidence for L-Valine as Preliminary (1 out of 5). It is backed by 2 clinical trials and 11 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(11 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Kaspy MS, Hannaian SJ, Bell ZW, Churchward-Venne TA The effects of branched-chain amino acids on muscle protein synthesis, muscle protein breakdown and associated molecular signalling responses in humans: an update Nutrition Research Reviews. 2024;37(2):273-286. doi: 10.1017/S0954422423000197.PubMedUsed to support: Review of the human data on branched-chain amino acids. BCAAs activate mTOR signalling and reduce indices of protein breakdown, and can transiently raise muscle protein synthesis at rest and after resistance exercise, with leucine named as the driver. The review's closing point is the limiting one: the muscle protein synthesis response to BCAAs is smaller than the response to a complete protein supplying all nine indispensable amino acids. No study in the review gave valine on its own.
  2. Weber MG, Dias SS, de Angelis TR, Fernandes EV, et al. The use of BCAA to decrease delayed-onset muscle soreness after a single bout of exercise: a systematic review and meta-analysis Amino Acids. 2021;53(11):1663-1678. doi: 10.1007/s00726-021-03089-2.PubMedUsed to support: Systematic review of ten randomized trials, nine of them pooled, on BCAA blends and delayed-onset muscle soreness after a single damaging exercise session. Seven of the ten trials found less soreness at 24 to 72 hours. The authors limit the conclusion to trained subjects, doses up to 255 mg/kg/day and mild to moderate muscle damage, and state that they cannot tell whether it works in untrained people or at higher doses. Valine was never given alone.
  3. Wu G Amino acids: metabolism, functions, and nutrition Amino Acids. 2009;37(1):1-17. doi: 10.1007/s00726-009-0269-0.PubMedUsed to support: Broad review of amino acid metabolism and nutrition. It provides the general background on amino acids as signalling molecules and precursors, and on the need for balance among dietary amino acids. It reports no finding specific to valine, and the amino acids it singles out as functionally active are arginine, cysteine, glutamine, leucine, proline and tryptophan.
  4. Kurpad AV, Regan MM, Raj TD, Gnanou JV, Rao VN, Young VR The daily valine requirement of healthy adult Indians determined by the 24-h indicator amino acid balance approach The American Journal of Clinical Nutrition. 2005;82(2):373-9. doi: 10.1093/ajcn.82.2.373.PubMedUsed to support: Eighteen healthy, well-nourished Indian men were studied across graded valine intakes ranging from 5 to 35 mg/kg/day, with phenylalanine oxidation and balance tracked by a 24-hour carbon-13 tracer. The breakpoint fell at 17 mg/kg/day, which the authors propose as the mean valine requirement for healthy adults. Work of this kind is what establishes valine as genuinely required; the US RDA of 24 mg/kg/day comes from a separate Institute of Medicine analysis that adds a safety margin to an estimated average requirement of 19 mg/kg/day.
  5. Guttuso T, McDermott MP, Su H, Kieburtz K Effects of L-isoleucine and L-valine on hot flushes and serum homocysteine: a randomized controlled trial Obstetrics and Gynecology. 2008;112(1):109-15. doi: 10.1097/AOG.0b013e31817d53b6.PubMedUsed to support: A 22-week randomized trial in 100 postmenopausal women having at least five moderate to severe hot flushes a day, using 5 g/day of amino acid in capsules. In the placebo-controlled first phase, L-isoleucine did not beat placebo on hot flushes (13.9% reduction versus 25% on placebo, p = 0.28). In the second phase every woman received L-valine, alone or with L-isoleucine, and fasting serum homocysteine did not change on any of the amino acid regimens. This is one of the few trials that gave L-valine to people on its own, and it produced no measurable effect; note that valine itself was never compared against placebo for hot flushes.
  6. Lynch CJ, Adams SH Branched-chain amino acids in metabolic signalling and insulin resistance Nature Reviews Endocrinology. 2014;10(12):723-36. doi: 10.1038/nrendo.2014.171.PubMedUsed to support: Reviews the finding that circulating BCAA levels run higher in people with obesity and track with worse metabolic health and with later insulin resistance and type 2 diabetes. The review is explicit that the direction of causation is unsettled: insulin resistance may itself raise blood amino acid levels, and the leading mechanistic candidates involve leucine-driven mTORC1 signalling and accumulation of BCAA breakdown intermediates rather than valine.
  7. Kephart WC, Mumford PW, McCloskey AE, Holland AM, Shake JJ, Mobley CB, Jagodinsky AE, Weimar WH, Oliver GD, Young KC, Moon JR, Roberts MD Post-exercise branched chain amino acid supplementation does not affect recovery markers following three consecutive high intensity resistance training bouts compared to carbohydrate supplementation Journal of the International Society of Sports Nutrition. 2016;13:30. doi: 10.1186/s12970-016-0142-y.PubMedUsed to support: Thirty resistance-trained men did three consecutive days of heavy back squats and took either a BCAA blend supplying 2 g/day of L-valine with leucine and isoleucine, or carbohydrate alone. Squat 1RM and isokinetic peak torque dropped by the same amount in both groups, and serum myoglobin and perceived soreness rose in both groups regardless of supplement. A negative result that sits alongside the positive soreness meta-analyses.
  8. Elovaris RA, Fitzgerald PCE, Bitarafan V, Ullrich SS, Horowitz M, Feinle-Bisset C Intraduodenal Administration of L-Valine Has No Effect on Antropyloroduodenal Pressures, Plasma Cholecystokinin Concentrations or Energy Intake in Healthy, Lean Men Nutrients. 2019;11(1):99. doi: 10.3390/nu11010099.PubMedUsed to support: One of the very few human studies of valine given on its own. Twelve healthy lean men received 90-minute intraduodenal infusions of L-valine totalling 3.3 g or 9.9 g, or saline, in randomised double-blind order. Valine changed nothing: not gut pressures, cholecystokinin, blood glucose, appetite ratings or energy intake at the next meal (1040 kcal on control versus 1040 and 1056 kcal on valine). The amino acid was infused into the duodenum rather than swallowed, so the route is not the same as taking a capsule.
  9. Tsuda Y, Yamaguchi M, Noma T, Okaya E, Itoh H Combined Effect of Arginine, Valine, and Serine on Exercise-Induced Fatigue in Healthy Volunteers: A Randomized, Double-Blinded, Placebo-Controlled Crossover Study Nutrients. 2019;11(4):862. doi: 10.3390/nu11040862.PubMedUsed to support: Thirty-nine men took 3600 mg arginine plus 2200 mg valine plus 200 mg serine daily for 14 days, then cycled for 120 minutes at 50% of VO2max. Ratings of fatigue and perceived exertion were lower than on placebo. Valine was one of three ingredients, so no part of the result can be assigned to it, and all five authors are employees or officers of Meiji Co., the company that makes the mixture.
  10. Elango R Tolerable Upper Intake Level for Individual Amino Acids in Humans: A Narrative Review of Recent Clinical Studies Advances in Nutrition. 2023;14(4):885-894. doi: 10.1016/j.advnut.2023.04.004.PubMedUsed to support: Summarises human dose-response studies that produced the first upper intake levels or no-adverse-effect levels for ten amino acids, including leucine at 35 g/day in young adults and 30 g/day in older adults. Valine is not among the amino acids for which any upper limit has been determined, so the safe ceiling for isolated valine intake is unknown.
  11. Salem A, Ben Maaoui K, Jahrami H, AlMarzooqi MA, Boukhris O, Messai B, Clark CCT, Glenn JM, Ghazzaoui HA, Bragazzi NL, Ammar A, Trabelsi K, Chtourou H 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 Medicine - Open. 2024;10(1):42. doi: 10.1186/s40798-024-00686-9.PubMedUsed to support: Meta-analysis of 18 randomized trials of BCAA blends in healthy active adults. Creatine kinase fell immediately (Hedges g -0.44) and at 72 hours (g -0.99) but not at 24, 48 or 96 hours; muscle soreness fell at 24 to 96 hours (g -1.34 to -0.82) but not immediately; lactate dehydrogenase did not change at any time point. The supplement was a leucine-dominant blend, so the result cannot be attributed to valine.