What is HMB (β-Hydroxy-Methylbutyrate)?

HMB is an acronym for the leucine metabolite beta-hydroxy-beta-methylbutyrate, or more "simply," hydroxymethylbutyrate. HMB supplementation is a growing area of interest among the scientific community as this compound appears to mitigate exercise-induced muscle damage and enhance lean body mass (LBM) in active individuals that engage in resistance training. Hence, many bodybuilders and athletes are turning to HMB supplements for improving athletic performance, strength, and body composition.

But is HMB really effective, or is this another case of the hype outpacing the evidence? Let's see what research has to say about HMB supplementation and how it impacts aerobic and anaerobic capacity.

Is HMB Good for Muscle-Building?

A recent meta-analysis suggests that HMB supplementation in resistance-trained subjects can significantly increase strength during exercise [1]. Further evidence has shown that supplementing with HMB enhances muscle protein synthesis response after resistance training [2]. In other words, taking HMB may bolster skeletal muscle mass.

In addition, HMB appears to help athletes and gym-goers preserve fat-free mass (FFM) during a weight-loss program, specifically those who are new to resistance training [3]. HMB may also be beneficial for aerobic performance by increasing VO2 max [4].

Better yet, the ergogenic effects of HMB are synergistic with creatine monohydrate, meaning they complement one another and amplify results [5].

Based on the above, HMB probably sounds like the holy grail of sports supplements. So, what's the kicker? Well, it seems that HMB is most effective for reducing indices of muscle damage in untrained individuals and the elderly [6]. Essentially, it's an anti-catabolic agent.

However, HMB can still be a useful supplement for advanced trainees and athletes since its effects are optimized when combined with exercise. For improving strength and recovery between workouts, HMB is a promising candidate that tends to fly under the radar.

Is HMB a Steroid

No. HMB is an organic acid derived from the metabolism of leucine in skeletal muscle. It is not a performance-enhancing drug (PED) or anabolic steroid. Taking HMB as a dietary supplement is much safer than using steroids as PEDs.

How Does HMB work?

Beta-hydroxy-beta-methylbutyrate (HMB) is a natural metabolite of the essential branched-chain amino acid L-leucine. The majority of leucine that's ingested is utilized for muscle protein synthesis, while residual leucine is metabolized to alpha-ketoisocaproate (KIC) in muscle tissue. KIC is then metabolized to HMB, which acts as a signaling molecule that inhibits protein degradation [7].

Thus, HMB is particularly beneficial for preserving lean body mass during periods of caloric deprivation (e.g. when dieting for weight loss) and in elderly adults with sarcopenia, a chronic muscle-wasting condition.

HMB may also work through other physiological pathways, such as increasing cholesterol synthesis, modulating muscle bioenergetics, and reducing muscle cell apoptosis ("programmed death"), to enhance athletic performance and body composition [8].

HMB Supplementation: Dosage and Timing

For ergogenic purposes, the suggested HMB dosage ranges from 3 to 6 grams per day split across 2 to 3 doses. Even if you take other essential/branched-chain amino acids as a supplement, HMB can confer beneficial effects.

Currently, HMB supplements come in either the free acid form, beta-hydroxy-methylbutyric acid, or as a salt of its conjugate base, beta-hydroxy-methylbutyrate.

Transparent Labs Creatine HMB is formulated with patented Creapure and MyHMB (calcium-HMB) to support athletic performance and recovery. You can learn more about this foundational formula by clicking here.