The overall rating for leucine is 1.6 out of 3 meaning there is some evidence that this supplement does some (not all) of what it claims. Using this supplement may lead to some improvements.

Table of Contents

  1. Simple Report
  2. Detailed Report
  3. Overall Effectiveness Rating
  4. Research Rating
  5. Products Containing Leucine
  6. Claim Ratings
  7. Dosing
  8. References

Leucine Simple Report

  • Supplement: Leucine
  • Supplement Category: essential amino acids
  • Number of Products Containing Leucine: 109
  • Effectiveness Rating: 1.6 out of 3
  • Research Rating: 51 (above 80 indicates sufficient research)
  • Number of Studies: 11
  • Number of Claims: 7
  • Effective Dosage Range: 3.42 grams per day

Leucine Detailed Report

Overall Effectiveness Rating

The overall effectiveness rating for leucine is 1.6 out of 3. This rating means the evidence is mixed on the supplement's ability to deliver positive results. While some of the research supports its use, other evidence does not. Using this supplement may lead to positive results. Note, this effectiveness rating is for leucine as a whole; there are also individual ratings for the claims below.

Read more: What is the effectiveness rating?

Research Rating for Leucine

There are 11 studies in the database on leucine; the research rating is 51. A score above 80 means the effectiveness rating for this supplement is reliable. A score under 80 means there is insufficient evidence to ensure a reliable effectiveness rating. Note, this research rating is for leucine as a whole; there are also individual ratings for the claims below.

Read more: What is the research rating?

Products Containing Leucine

Products Names Amount of Leucine
Amino Shred 2.5g
Gain-O-Rade 1.5g
CYRx MD Pre-Workout 1g
Amino Lean Amount not listed.
Battle Mead Post Workout 2.5g
Full list of all 109 products containing Leucine.

Claim Ratings

The overall ratings above are an average of the individual claim ratings below. Individual claims may have higher or lower ratings compared to the supplement's overall rating. For example, some supplements may have excellent backing for one claim, but be completely useless for another. Click on a claim below for more information.

Body Composition (weight, muscle, body fat) Claims Effectiveness Rating Research Rating
increase muscle mass

Protein Synthesis Claims Effectiveness Rating Research Rating
decrease protein breakdown
increase protein synthesis

Performance Claims Effectiveness Rating Research Rating
increase strength

Recovery Claims Effectiveness Rating Research Rating
improve recovery
reduce muscle damage
reduce muscle soreness


The Supplement Database includes 5 studies on leucine dosing. These studies indicate an effective dose is 3.42 grams per day. For a more detailed dosing analysis visit: Supplement Dosing for Leucine.


Title of Study
Co-ingestion of leucine with protein does not further augment post-exercise muscle protein synthesis rates in elderly men.
Combined ingestion of protein and free leucine with carbohydrate increases postexercise muscle protein synthesis in vivo in male subjects
Effect of leucine supplementation on indices of muscle damage following drop jumps and resistance exercise
Effects of leucine and its metabolite β‐hydroxy‐β‐methylbutyrate on human skeletal muscle protein metabolism
Effects of Whey, Soy or Leucine Supplementation with 12 Weeks of Resistance Training on Strength, Body Composition, and Skeletal Muscle and Adipose Tissue Histological Attributes in College-Aged Males
Free leucine supplementation during an 8-week resistance training program does not increase muscle mass and strength in untrained young adult subjects
Hydrolyzed casein and whey protein meals comparably stimulate net whole-body protein synthesis in COPD patients with nutritional depletion without an additional effect of leucine co-ingestion
Leucine as a regulator of whole body and skeletal muscle protein metabolism in humans
Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis
Observations of Branched-Chain Amino Acid Administration in Humans
The Effects of Adding Leucine to Pre and Postexercise Carbohydrate Beverages on Acute Muscle Recovery From Resistance Training