HMB (β-Hydroxy β-Methylbutyrate)
Leucine metabolite; may reduce muscle protein breakdown.
By Suplagen Team · Updated
What it is
HMB is a metabolite of the branched-chain amino acid leucine. It's studied for anti-catabolic effects, particularly in trained individuals and older adults.
How it works
Inhibits the ubiquitin-proteasome proteolytic pathway; supports mTOR signaling and muscle protein synthesis.
What the evidence says
Moderate evidence for reducing muscle breakdown in untrained/elderly; less clear benefit in well-trained athletes.
How much to take
The catalog range is 1.5 to 3 g daily, and 3 g is also the ceiling. The moderate evidence for reducing muscle breakdown came from that range, mostly in untrained people and older adults.
If you're well-trained, the honest note: the benefit is less clear, and creatine remains the better spend. The free acid form absorbs faster than the calcium salt if you're choosing between them.
When and how to take it
Split it: 1 g three times daily, or 3 g with a meal if splitting is impractical. Take it every day, training or not, and give it at least 2 weeks before judging.
It stacks cleanly with creatine; the catalog lists the two as complementary. Both are daily saturation supplements rather than pre-workout ones.
Who should skip it
Severe kidney disease is a caution. The one listed drug interaction is statins, at a mild level. Pregnancy safety isn't established. Otherwise HMB is well tolerated at catalog doses.
Safety Notes
- Most beneficial for untrained individuals or older adults at risk of muscle loss. Free acid form absorbs faster.
- Use caution with: severe kidney disease (caution).
- statins: Both affect cholesterol pathways; theoretical interaction. Monitor.
Timing With Other Supplements
- Creatine Monohydrate: Complementary; often stacked together for muscle support.
Common questions
How much HMB should I take a day?
1.5 to 3 g, with 3 g as the ceiling. Split into 1 g doses across the day for the most consistent coverage.
When should HMB be taken?
Any time, as long as it's daily. With meals is convenient; post-workout is a fine slot but not required. Consistency for 2 or more weeks is what matters.
Does HMB work if you already train?
Less clearly. The evidence concentrates in untrained people and older adults at risk of muscle loss. For seasoned lifters, creatine has the stronger case.