What is the significance of Beta-Hydroxy Beta-Methylbutyrate (HMB)?

From the Guidelines

HMB, or beta-hydroxy beta-methylbutyrate, is a supplement that may help with muscle recovery and growth, particularly in elderly populations or those experiencing muscle loss, with a typical recommended dosage of 3 grams per day. The significance of HMB lies in its potential to reduce muscle protein breakdown and enhance protein synthesis, which can be beneficial during periods of intense exercise or caloric restriction 1. HMB appears most effective for individuals who are new to training, returning after a break, or elderly populations experiencing muscle loss. Some key points to consider when using HMB include:

• The typical recommended dosage is 3 grams per day, usually divided into three 1-gram doses taken with meals.
• HMB works by potentially reducing muscle protein breakdown and enhancing protein synthesis.
• It is especially beneficial during periods of intense exercise or caloric restriction.
• HMB appears most effective for individuals who are new to training, returning after a break, or elderly populations experiencing muscle loss.
• While generally considered safe with minimal side effects, it's always advisable to consult with a healthcare provider before starting any new supplement, especially if you have existing health conditions or take medications.
• For optimal results, combine HMB supplementation with proper nutrition and a consistent exercise program rather than relying on it as a standalone solution 1. In terms of specific populations, HMB may be particularly beneficial for older adults, as it has been shown to reduce muscle loss and increase muscle mass gain during periods of bedrest or immobilization 1. Additionally, HMB may be useful for cancer patients, as it has been claimed to be an anti-catabolic agent that minimizes protein breakdown 1. However, more research is needed to fully understand the effects of HMB in these populations.

From the Research

Significance of Beta-Hydroxy Beta-Methylbutyrate (HMB)

• HMB is a metabolite of the branched-chain amino acid leucine, used by athletes and bodybuilders to increase strength, muscle mass, and exercise performance 2.
• The supplement has been shown to be effective in preventing exercise-related muscle damage in healthy trained and untrained individuals, as well as muscle loss during chronic diseases 2, 3.
• HMB can enhance recovery by attenuating exercise-induced skeletal muscle damage, and its effectiveness is increased when consumed in close proximity to workouts 3.

Mechanisms of Action

• HMB's mechanisms of action include inhibition of proteolysis and increase of protein synthesis, respectively 2, 3.
• The supplement has been shown to reduce muscle-damage-induced inflammation and oxidative stress, and promote cellular cholesterol synthesis 4.
• HMB may also stimulate the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis and enhance muscle stem cells proliferation and differentiation 5.

Effects on Physical Performance

• HMB supplementation has been shown to have positive effects on specific aerobic capacity variables in endurance and martial arts athletes 5.
• In resistance-trained athletes, HMB supplementation has been linked to changes in strength, body fat, and muscle mass, as well as anaerobic performance and power output 5.
• The supplement may also attenuate the development of sarcopenia in elderly subjects, particularly when combined with exercise 6.

Safety and Dosage

• The usual dose of HMB is 3 g/day, which may be routinely recommended to maintain or improve muscle mass and function in health and disease 2.
• HMB has been demonstrated to be safe in both young and old populations, with chronic consumption showing no adverse effects 3.
• The timing and duration of HMB intake can vary, with chronic intake (≥ 2 weeks) and acute intake (30-60 min before exercise) showing different effects 4.