HMB, otherwise known as beta-hydroxy-beta-methylbutyrate, is a metabolite of leucine that helps reduce protein breakdown, thereby retaining muscle strength and assisting with improved body composition.

[36] performed an extensive two-part experiment to test the effects of HMB supplementation on muscle metabolism during resistance-exercise training. Results found no adverse side effects from HMB supplementation.

beta-hydroxy-beta-methylbutyrate (HMB) supplementation in humans is safe and may decrease cardiovascular risk factors.

HMB is POSSIBLY SAFE for most people when taken by mouth, short-term. Doses of 3 grams per day or less for up to 8 weeks seem to be safe.

It is recommended to take HMB supplements around one hour before you work out. You can also take HMB immediately post-workout. This ensures HMB levels are replenished following intense exercise. It is important to take HMB consistently every day for optimal results.

HMB is a metabolite derived from the essential amino acid leucine. Some studies have suggested that HMB is an anabolic compound that increases muscle building after resistance exercise training and improves lean body mass.

It found that when athletes took 3–6 grams of HMB daily for a period of 3 days to 12 weeks, they experienced no increases in strength or changes body composition ( 11 ). In short, research on HMB and muscle growth shows mixed results.

While HMB is produced naturally by your body, taking it as a supplement allows for higher levels and may benefit your muscles (40, 41 ). Several studies in previously untrained adults have shown taking 3–6 grams of HMB per day can improve the gains in lean body mass from weight training ( 42 , 43 , 44 ).

In brief, HMB supplementation is effective in increasing myofibrillar protein synthesis via the mTOR pathway and the growth hormone/IGF-1 axis, and in preventing muscle protein breakdown via the ubiquitin proteasome and the autophagy-lysosome systems.

β-hydroxy β-methylbutyrate (HMB) is a naturally produced substance regarded as safe and effective in preventing muscle loss during chronic diseases….HMB for Denutrition in Patients With Cirrhosis (HEPATIC) (HEPATIC)

Early research shows that HMB can lower cholesterol. High blood pressure. Early research shows that HMB can lower blood pressure.

No, HMB does not burn fat. Although HMB is a common ingredient in high quality fat burner supplements, it is not actually a fat burner itself.

You should really take no more than 5g of HMB per day. Most studies showing fantastic benefits from HMB used 3g per day, usually taken pre-workout. Doses above 5g per day of HMB appear to produce rapidly diminishing returns. That means you don’t get any extra benefit when consuming more than 3-5g of HMB each day.

But supplementing with the amino acid HMB (beta-hydroxy beta-methylbutyrate) has been shown to delay the breakdown of muscle protein, promote tissue growth and strengthen the immune system. So again adding a few grams of this to your bedtime shake could help to make your sleep more anabolic and less catabolic.

So not only can you take HMB every day, you should take HMB every day while cutting if you want to minimize fat loss and maximize lean muscle mass retention.

The combination of HMB and creatine monohydrate supplementation does not provide a greater ergogenic benefit compared to creatine monohydrate supplementation alone. Body composition, strength, and sprinting ability did not change across the season with creatine monohydrate supplementation.

Interestingly, although orally supplied HMB produced no increase in plasma insulin, it caused a depression in MPB (−57%).

HMB and Creatine Monohydrate, when combined, have been shown to increase endurance, enhance strength, help decrease fat mass and even prevent lean muscle loss.

Data published in Biomolecules ​indicated that creatine monohydrate (CrM) and beta-hydroxy beta-methylbutyrate (HMB) supplementation for 10 weeks increased testosterone levels and the effects were significantly greater than an additive effect.

Conclusion: The results indicate that HMB supplementation in athletes can reduce the concentration of cortisol in resistance exercises and increase the concentration of testosterone in aerobic and anaerobic combined exercises.