closeup of hmb supplements

What is HMB?

23 Nov 2022 • 1 min read


In the UK, 1 in 7 of us hold a gym membership.1 Whether we’re lifting in the weight room or taking part in an intense HIIT class, more and more of us are looking for ways to improve our overall fitness and wellbeing.

With this in mind, it’s unsurprising that many of us look to supplements and fitness aids to improve the effects of our workouts. Whether you regularly browse the shelves in your local sports store or look online for training tips, you might have seen some information about HMB.

If you’re wondering whether HMB is the right type of supplement for you, you can find everything you need to know below.

What is HMB?

HMB is a type of molecule that’s produced when your body processes an amino acid called leucine.2 Its official name is beta-hydroxy beta-methylbutyrate, but you’ll likely see it on the shelves as ‘HMB.’

HMB is naturally produced by your body, which means you may not need to supplement it. However, some people choose to take it in higher dosages for a range of reported benefits.3

HMB supplements are usually sold in capsule or powder form. They might be mixed with other ingredients or sold as single-ingredient products. There are currently two forms of HMB available: Calcium HMB (HMB-Ca) and a free acid form of HMB (HMB-FA). At the moment, there isn’t a lot of evidence to say which one is better.4

What does HMB do?

Like with any supplement, it’s essential to proceed with caution when adding HMB to your health routine. While research is underway, it’s not always clear how taking additional supplements will interact with the body. If you have any concerns, it’s best to speak to your doctor first.

As a by-product of leucine, it’s thought that HMB can help to reduce or prevent the breakdown of muscle.5 There are other associated benefits, which might include:

  • Muscle loss6
  • Muscle strength7
  • Muscle gains8
  • Reduced blood pressure9
  • Athletic performance10
  • Heart health11

However, it’s worth noting that studies are quite limited on the overall effects of HMB.

In terms of muscle gain and strength, some studies have suggested that HMB is most useful for people unused to exercise or strength training. It’s not clear how well HMB supplements would work for people who already weight train.12,13

Potential side effects

On the whole, it’s thought that HMB is a reasonably safe supplement for most people.14 It’s always a good idea to talk to your doctor before taking it, especially if you are on other medications.

While clinical studies haven’t revealed concerning side effects, it’s also worth remembering that this doesn’t mean there aren’t any.15,16

If you notice any unwanted symptoms when taking HMB, stop using your supplement and speak to your doctor if you have any concerns.

Last updated: 24 March 2021



Author: Bhupesh PanchalSenior Regulatory Affairs Associate

Joined Holland & Barrett: Apr 2019

Masters Degree in Toxicology and BSc Hons in Medical Biochemistry

Bhupesh started his career as a Clinical Toxicologist for Public Health England, advising healthcare professionals all around the country on how to manage clinical cases of adverse exposure to supplements, pharmaceuticals, cosmetics, industrial chemicals and agricultural products.

After 7 years in this role and a further year working as a drug safety officer in the pharmaceutical industry, Bhupesh joined Holland & Barrett as a Senior Regulatory Affairs Associate in 2019.

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