HMB Supplements

What is HMB?

HMB (beta-hydroxy beta-methylbutyrate) is a compound your body makes from leucine, one of the branched-chain amino acids. Only a small proportion of the leucine you eat is turned into HMB, which is why it's sold as a supplement.

It isn't a protein or an amino acid itself, so it isn't covered by the protein claims on the authorised health claims list, and there are no authorised health claims for HMB in Great Britain.

What does HMB do?

The research is mixed. The International Society of Sports Nutrition (ISSN) position stand on HMB concluded that HMB "can be used to enhance recovery by attenuating exercise induced skeletal muscle damage" (that is, reduce muscle damage caused by exercise) in trained and untrained people, and that it increased lean body mass (muscle and other non-fat tissue) and physical function in older, inactive people.

A more recent 2025 review was more cautious: it found that HMB was largely neutral in well-fed, resistance-trained groups, that any effects were mainly seen under heavy training stress or calorie restriction, and that many positive trials were industry-funded. We don't claim HMB builds muscle or helps you recover.

Does HMB work for people who already train?

For well-fed people who already lift weights, the 2025 review describes the effect as largely neutral. That's the group most likely to be shopping for HMB, so it's worth knowing before you buy.

"Where evidence is limited or inconclusive, we should say so openly," says Andy Arshad, who runs SupplementHQ.

If your main interest is muscle, the authorised claim that exists is for protein: "Protein contributes to a growth in muscle mass", for foods that are at least a source of protein.

How much HMB should you take?

The ISSN position stand reports that the research used 38mg of HMB per kg of body weight a day. For an 80kg person that's about 3g a day. Follow the directions on your product's label.

Capsules often contain 500mg to 1,000mg each, so check how many make a daily dose. The ISSN stand also notes HMB appeared most effective when taken for about two weeks before an exercise period.

Calcium HMB or free-acid HMB?

Most HMB products use calcium HMB (HMB-Ca). The ISSN stand says free-acid HMB (HMB-FA) may be absorbed and retained better, but the evidence is limited and doesn't show that one form is better than the other.

Calcium HMB contributes some calcium; if you take a calcium supplement too, add up the total. Check the label for which form a product uses.

Is HMB safe?

The ISSN position stand concluded that chronic consumption of HMB is safe in both young and old populations, based on the studies it reviewed. That's not a guarantee for every person.

If you have a medical condition, take medication, or are pregnant or breastfeeding, speak to your GP or pharmacist before taking HMB.

Should you take HMB with creatine?

That's your choice, but there's no authorised claim for the combination. Creatine does have an authorised claim: "Creatine increases physical performance in successive bursts of short-term, high intensity exercise", where a product provides 3g of creatine a day, according to the GB claims list.

Some products here combine creatine and HMB. Check the grams of each per serving, and compare with plain creatine.

How to compare value

How to compare value (example figures, not real products): a £20 pot of 180 capsules with 1,000mg HMB each, taken three a day for 3g, lasts 60 days and costs about 33p a day. A £15 pot of 120 capsules with 500mg each needs six a day for 3g, lasts 20 days and costs 75p a day, more than twice as much.

"We think customers should compare the actual amount of active ingredients they're getting, rather than just the format or marketing," says Andy. Our guide to reading a supplement label shows where to find the amounts.

Which is the best HMB supplement?

If you've decided to try HMB, the best one for you states the grams of HMB per daily dose clearly, names the form and has a sensible cost per day. Added ingredients don't make it better.

Browse the rest of our amino acids & recovery range.

We sell the products on this page. That's our commercial interest, and it's why we show the evidence alongside them. This page is general information for adults, not personalised medical advice. Food supplements should not replace a varied, balanced diet.

Written by Andy Arshad, SupplementHQ. Last reviewed 11 October 2026.