HMB, or beta-hydroxy beta-methylbutyrate, is a substance produced naturally in the body during the breakdown of the essential amino acid leucine. It is a popular dietary supplement known for its benefits in reducing muscle protein breakdown and enhancing muscle protein synthesis.

Hydroxymethylbutyrate (HMB) is a substance naturally produced in small amounts when your body breaks down the amino acid leucine. HMB works to help repair the structure and function of your muscles. HMB is available in small amounts in some foods, such as grapefruit, alfalfa, and catfish, and as a dietary supplement.

HMB is a metabolite of leucine, one of the 3 branched-chain amino acids (BCAAs), along with valine and isoleucine. As a supplement, HMB is often used to improve muscle protein synthesis and reduce muscle loss over time.

HMB or Beta-Hydroxy Beta-Methylbutyrate is a chemical that’s made when your body breaks down an amino acid called leucine. HMB rolls off the tongue a little easier, so you’ll likely see it called this on the shelves, on social media and online. "Leucine triggers the process of muscle protein synthesis, and HMB is produced at the same time"

What is hydroxymethylbutyrate (HMB)? HMB, short for (take a breath) Hydroxymethylbutyrate, is a natural compound your body produces when it breaks down leucine, a critical amino acid for muscle repair and growth. HMB is said to help protect muscles from breaking down and help them grow and adapt over time.