HMB and Vitamin D: Improving functionality in older adults

In aging, muscle mass declines, as does physical performance. Stopping age-related muscle loss is important for healthspan and overall wellness in aging. For example, more muscle mass may protect you from falls and from osteoporosis.

Hydroxy-β-methylbutyrate (HMB) is a metabolite of leucine, an amino acid. Studies have shown beneficial effects of supplements hydroxy-β-methylbutyrate on muscle mass and strength, including in aging.[ref][ref] It is now a popular body building supplement.

HMB is referred to in study as β-Hydroxy β-Methylbutyrate or Hydroxy β-Methylbutyrate. It is derived from leucine using the enzyme KIC dioxygenase, which is also known as 4-Hydroxyphenylpyruvate dioxygenase (HPPD).[ref]

A recent double-blind clinical trial in people over age 60 looked at how HMB and vitamin D affect older people’s functionality (strength, lean body mass, movement).

The trial had four arms: control with no exercise, HMB + vitamin D with no exercise, control plus exercise, and HMB + vitamin D with exercise.

The 12-month long study looked at benefits on body composition, lean body mass, strength, and functionality — which all together the researchers called the functional index. In the HMB + Vitamin D and no exercise group, there was an increase in the functional index compared to control. Adding exercise didn’t improve the functional index compared to control with exercise.[ref]

Want to know more about HMB? Check out the article, which links to a bunch of clinical trials on HMB.


The clinical trial used 3.0 g/day of HMB, split into two doses. Added to that was 2,000 IU/day of vitamin D3. The 3.0 g/day of HMB in split doses seems to be a typical dose. Many supplements offer it in 1.5 g per serving.


While these supplements are generally safe, there are some potential side effects, such as nausea and diarrhea. It is important to be aware of these side effects so that you can stop taking the supplements if you experience them. Talk with your doctor if you have questions before taking any supplements, especially if you have any health conditions.

Get the stack:

Nutricost HMB 1,000 mg plus vitamin D3 (4,000 IU) is available on Amazon with good reviews.

If you already take vitamin D (or get plenty of sun and don’t need to supplement), you can get HMB as a bulk powder on Amazon also. Doublewood supplements also offers a 1,000 mg HMB capsule, which is made in the US.

Disclaimer: The information in the article is not intended to be a substitute for medical advice.