OnePin Peptide Library · Performance
HMB
Beta-Hydroxy Beta-Methylbutyrate
HMB (β-Hydroxy-β-Methylbutyrate) is a metabolite of the branched-chain amino acid leucine. Approximately 5% of dietary leucine is converted to HMB in the body. Used in clinical and sports contexts to reduce muscle protein breakdown, support recovery, and prevent muscle loss in catabolic states (bedrest, illness, severe caloric restriction).
Divided doses or pre-workout.
Start here. Every protocol below is ordered lowest-first. Begin at the smallest effective dose, hold about a week to assess tolerance, and step up only if needed.
How it works
HMB acts through multiple anti-catabolic mechanisms:
Reduced Muscle Protein Breakdown
HMB decreases ubiquitin-proteasome activity, reducing muscle protein degradation. This is the primary mechanism.
Improved Cell Membrane Integrity
HMB is a precursor for cholesterol synthesis - supports muscle cell membrane stability under stress.
Reduced Muscle Damage
Lower CK and LDH elevation post-exercise indicate reduced muscle damage.
Modest Anabolic Signaling
Some mTOR pathway activation, but effect is smaller than leucine alone.
Particularly Useful in Catabolic States
Effect sizes larger when baseline catabolism is high (caloric deficit, bedrest, illness, sarcopenia).
What to expect
Days 1-14: subtle effects.
Weeks 4-12: peak effects in catabolic contexts.
Long-term: sustained anti-catabolic with continued use.
Evidence
Interactions & stacking
What's safe to combine, and what belongs in a separate pin.
Keep separate
Side effects & safety
Commonly reported
- Generally well-tolerated
- Mild GI possible
Less common & notes
- Allergic reactions rare.
- Long-term safety good.
Pharmacokinetics
Storage. Capsule/powder. Cool dry location.
Regulatory status
Dietary supplement (US, DSHEA). Used in some clinical nutrition products.
Put it to work
Calculate, log & track
Open HMB straight into OnePin with your vial and dose pre-filled, then let it handle the syringe math and remind you before the vial runs out.
Open HMB in the app →Go deeper
The guide & community
The complete HMB walkthrough, real protocol discussion and coaching live inside the BlessUp community on Skool.
Join the community ↗