HMB
ColorantsCAS: 625-08-1
This is what the ingredient is.
HMB (β-Hydroxy β-methylbutyric acid) is a metabolite of leucine studied for muscle preservation and growth.
Here is why it shows up on the label.
Used to reduce muscle breakdown and support muscle maintenance, particularly during caloric restriction.
Here is what food agencies say.
The FDA lists it as Generally Recognized as Safe. reviewed. Available as dietary supplement.
Here is what research has found.
Studies suggest benefits for preventing muscle loss. More effective in untrained individuals and clinical settings.
Here are a few things worth knowing.
Generally safe. May cause mild GI effects. Less effective for trained athletes.
Sources
- FDA GRAS Notice
- JISSN
- Nutrition & Metabolism
How to read this page
We publish plain facts about this ingredient so a label is easier to read. This is not medical advice, and it is not a recommendation to buy, avoid, or use anything. For a personal health question, talk with a clinician who knows your history.
v1.0Updated 9/12/2026