Leucine

8 research sources Also known as: l-leucine leucine supplement branched chain amino acid
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17.4 gram(s) Median Dose
🟢 99/100 Market Safety Score
8 Research Sources
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Evidence Summary

L-Leucine is a branched-chain amino acid (BCAA) primarily studied for its role in stimulating muscle protein synthesis and preventing muscle wasting. Research indicates its potential utility in managing muscle loss in specific populations, such as the elderly and those suffering from critical illness or malnutrition.

Evidence by Condition

Sarcopenia Moderate

Meta-analysis suggests that supplementation with whey protein, leucine, and Vitamin D can be effective in treating sarcopenia.

Critical Illness Insufficient

Research is investigating whether leucine-enriched BCAAs can improve muscle thickness and reduce inflammatory markers like IL-6 in critically ill patients.

Clinical trials are exploring whether supplemental leucine can offset muscle loss caused by periods of inactivity.

Malnutrition (COPD) Insufficient

Studies have looked at adding leucine to protein supplements to induce protein anabolism in malnourished COPD patients.

Effective Doses

Dose ranges were not specified in the provided research abstracts.

Key Findings

  • A meta-analysis supports the use of whey protein, leucine, and Vitamin D for patients with sarcopenia (PMID: 36771225).
  • Leucine-enriched BCAAs are being studied for their impact on muscle thickness and SOFA scores in critical illness (NCT06167772).
  • Leucine supplementation is being investigated for its ability to prevent disuse-induced muscle atrophy (NCT03762278).

Limitations

Much of the available research focuses on small-scale clinical trials or specific clinical populations (e.g., the elderly or critically ill), leaving a gap in evidence for healthy, young populations.

Safety & Interactions

No specific contraindications or drug interactions were identified in the provided research.

AI-generated summary from 8 peer-reviewed studies. Not medical advice. Always consult a healthcare provider.

Claims vs. Evidence

100% Evidence-Backed
0% Unsupported
90% Structure/Function
Claim Type% of ProductsEvidence RequiredStatus
All Other 100% Tier D (Unclassified) ✅ Supported
Structure/Function 90% Tier C (DSHEA Structure/Function (no pre-approval)) ✅ Supported
Nutrient 56% Tier D (Unknown) ✅ Supported

Research by Topic

Research Evidence (8)

Clinical Trial: 7 Meta Analysis: 1
B Effects of Whey Protein, Leucine, and Vitamin D Supplementation in Patients with Sarcopenia: A Systematic Review and Meta-Analysis
Meta Analysis Nutrients 2023 n=637

**Chang et al., 2023** | Nutrients | Meta Analysis Chang Min Cheol, Choo Yoo Jin. Effects of Whey Protein, Leucine, and Vitamin D Supplementation in Patients with Sarcopenia: A Systematic Review and Meta-Analysis. Nutrients. 2023-Jan-19;15(3). doi:10...

C Leucine-enriched Branched-chain Amino Acid on Muscle Thickness, Interleukin-6, SOFA Score in Critical Illness
Clinical Trial ClinicalTrials.gov 2023

**NCT ID**: NCT06167772 **Phase**: NA **Status**: COMPLETED **Enrollment**: 40 **Completion**: 2024-05-10

C The Effects of Leucine Metabolites in Performance, Body Composition and Biochemical Markers of Muscle Damage
Clinical Trial ClinicalTrials.gov 2017

**NCT ID**: NCT03511092 **Phase**: NA **Status**: COMPLETED **Enrollment**: 53 **Completion**: 2017-10-28

C Can Supplemental Leucine Offset Disuse-induced Muscle Atrophy?
Clinical Trial ClinicalTrials.gov 2017

**NCT ID**: NCT03762278 **Phase**: NA **Status**: COMPLETED **Enrollment**: 24 **Completion**: 2019-05-01

C Leucine Supplementation in Sarcopenic Older Individuals
Clinical Trial ClinicalTrials.gov 2019

**NCT ID**: NCT03831399 **Phase**: PHASE1 **Status**: COMPLETED **Enrollment**: 59 **Completion**: 2019-10-14

C The Effect of Leucine on Carnitine Transport to Skeletal Muscle
Clinical Trial ClinicalTrials.gov 2016

**NCT ID**: NCT05009654 **Phase**: NA **Status**: COMPLETED **Enrollment**: 16 **Completion**: 2018-01-31

C Hydrolyzed Casein and Whey Protein Supplementation and the Addition of Leucine to Induce Protein Anabolism in Malnourished COPD Patients
Clinical Trial ClinicalTrials.gov 2009

**NCT ID**: NCT01154400 **Phase**: NA **Status**: COMPLETED **Enrollment**: 12 **Completion**: 2011-07

C Resistance Exercise Training and Amino Acid Leucine Supplementation in Frail Elderly Women
Clinical Trial ClinicalTrials.gov 2013

**NCT ID**: NCT01922167 **Phase**: NA **Status**: COMPLETED **Enrollment**: 19 **Completion**: 2018-12-17

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Frequently Asked Questions

What is L-Leucine and how does it work?

L-Leucine is a branched-chain amino acid (BCAA) that plays a key role in stimulating muscle protein synthesis. It is primarily studied for its potential to help prevent muscle wasting.

Does L-Leucine help with sarcopenia?

There is moderate evidence suggesting that a combination of leucine, whey protein, and Vitamin D can be effective in treating sarcopenia. This may be particularly useful for elderly populations.

Can L-Leucine prevent muscle loss from inactivity?

There is currently insufficient evidence to confirm if leucine supplementation can offset muscle atrophy caused by periods of disuse. Clinical trials are still investigating this potential benefit.

Is L-Leucine effective for patients in critical illness?

There is currently insufficient evidence regarding the use of leucine-enriched BCAAs for critically ill patients. Researchers are still studying whether it can improve muscle thickness or reduce inflammatory markers.

Can L-Leucine help with malnutrition in COPD patients?

There is insufficient evidence to determine if adding leucine to protein supplements helps malnourished COPD patients. Studies are ongoing to see if it can effectively induce protein anabolism in this group.

Are there any side effects or drug interactions with L-Leucine?

No specific drug interactions or contraindications have been identified in the available research. However, no specific groups to avoid or safety limits were documented in the provided studies.

What is the recommended dose of L-Leucine?

The provided research does not specify an effective or recommended dose range for L-Leucine. You should consult a healthcare professional for personalized dosing advice.

Answers generated from research evidence. Not medical advice.