Supplement

Valine

L-Valine

Evidence TierCWADA NOT PROHIBITED

tuneTypical Dose

1-3

watchEffect Window

Acute to weeks depending on context.

check_circleCompliance

WADA NOT PROHIBITED

Overview

Clinical Summary

Valine is an amino acid or related metabolite involved in protein turnover and cellular signaling. It is taken to support exercise performance, recovery, or specific metabolic pathways.

Evidence is context dependent. Trials most often evaluate exercise outcomes such as fatigue, blood flow, or muscle soreness, and some show small benefits at adequate doses. Minority uses include support for wound healing, immune function, and sleep quality. Effects vary with baseline protein intake, training status, and coingested nutrients.

Essential branched-chain amino acid with strong physiological importance, but limited direct standalone supplementation efficacy evidence.

Outcomes

What This Is Expected To Influence

Primary Outcomes

  • Clinical nutrition support (BCAA context)
  • Exercise recovery support (BCAA context)

Secondary Outcomes

  • Fatigue-support signal
  • Protein-balance support

Safety

Contraindications and Interactions

Contraindications

  • Inborn amino-acid metabolism disorders
  • Severe renal disease without supervision
  • Complex liver disease without clinical guidance

Side effects

  • GI upset
  • Nausea
  • Amino-acid imbalance at high isolated doses

Interactions

  • High-protein/BCAA stacking
  • Complex metabolic therapy regimens
  • Limited direct drug interaction data

Avoid if

  • Expectation of strong valine-only ergogenic effect
  • Unsupervised chronic disease use
  • Pregnancy/breastfeeding without advice

Evidence

Study-level References

valine-SRC-001Systematic review/meta-analysis.
Sourceopen_in_new

Cochrane review of BCAA for hepatic encephalopathy (PMID: 28518283, 2017).

Population: People with cirrhosis/hepatic encephalopathy.

Dose protocol: BCAA interventions.

Key findings: Clinical improvement signal in selected outcomes.

Notes: Mixed trial quality.

Paper content

Clinical improvement signal in selected outcomes.

valine-SRC-002Systematic review/meta-analysis.
Sourceopen_in_new

Meta-analysis of BCAA supplementation in liver cirrhosis (PMID: 35500317, 2022).

Population: Adults with cirrhosis.

Dose protocol: Various BCAA regimens.

Key findings: Supports targeted clinical benefit.

Notes: Protocol heterogeneity.

Paper content

Supports targeted clinical benefit.

valine-SRC-003Systematic review
Sourceopen_in_new

Martinho DV et al. Nutrients. 2022. doi: 10.3390/nu14194002; PMID: 36235655. (Systematic review including athletes)

Population: 24 studies in athletic/physically active adults

Dose protocol: BCAA peri-exercise regimens.

Key findings: Mixed-to-modest recovery effects.

Notes: Performance endpoints highly variable.

Paper content

Aggregate anabolic signaling effects are plausible, but performance/body-composition gains are generally negligible/heterogeneous.

valine-SRC-004Systematic review and meta-analysis with meta-regression
Sourceopen_in_new

Salem A, Ben Maaoui K, Jahrami H, 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. doi:10.1186/s40798-024-00686-9. PMID:38625669.

Population: Healthy active participants performing resistance or endurance exercise across 18 RCTs.

Dose protocol: Acute/chronic BCAA supplementation.

Key findings: Reduction in soreness biomarkers.

Notes: Study heterogeneity and publication bias risk.

Paper content

This meta-analysis of 18 RCTs examined BCAA supplementation for exercise-induced muscle damage. BCAAs significantly reduced creatine kinase immediately (g = -0.44, P = 0.006) and at 72 hours post-exercise (g = -0.99, P = 0.002). Delayed onset muscle soreness was significantly lower at 24 through 96 hours, with the largest effect at 72 hours (g = -1.82). LDH was not significantly affected. Longer supplementation periods yielded greater benefits. The findings support BCAAs for reducing muscle damage biomarkers and soreness but not for all damage markers.

valine-SRC-005Pilot randomized placebo-controlled trial.
Sourceopen_in_new

BCAA timing pilot placebo-controlled trial (PMID: 28944645, 2018).

Population: Exercise-trained participants.

Dose protocol: Timed BCAA around exercise.

Key findings: Timing-related minor recovery differences.

Notes: Small sample size.

Paper content

Timing-related minor recovery differences.

valine-SRC-006RCT
Sourceopen_in_new

Luan C, Wang Y, Li J, et al. Branched-Chain Amino Acid Supplementation Enhances Substrate Metabolism, Exercise Efficiency and Reduces Post-Exercise Fatigue in Active Young Males. Nutrients. 2025;17(7):1290. doi:10.3390/nu17071290. PMID:40219047.

Population: Active young males

Dose protocol: BCAA (leucine, isoleucine, valine) twice daily for 3 days, crossover design

Key findings: Enhanced fat oxidation, cycling efficiency, and reduced post-exercise fatigue in active young males. Cannot isolate valine's individual contribution.

Notes: Very small sample (n=11), short duration (3 days). Confirms BCAA mixture effects but not valine-specific benefits.

Paper content

This double-blind crossover RCT in 11 active males found that 3-day BCAA supplementation enhanced fat oxidation during constant load exercise, increased carbohydrate oxidation and cycling efficiency during high-intensity exercise, and reduced post-exercise fatigue and blood ammonia levels.

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