HMB Free Acid

A rapidly absorbed form of HMB that may enhance muscle recovery and growth.

Also known as: Beta-Hydroxy-Beta-Methylbutyrate Free Acid • HMB-FA

other Names
Beta-Hydroxy-Beta-Methylbutyrate Free Acid
primary Benefits
Reduces muscle damage, improves recovery, supports lean mass.
common Dose
1,000 mg (1 gram)
best Form
Free Acid Gel Capsule
timing
30-60 minutes before exercise.
safety Rating
Generally safe with a good safety profile.

Overview

HMB Free Acid (HMB-FA) is a newer, faster-absorbing form of HMB, a metabolite of the amino acid leucine. It is studied for its potential to reduce muscle protein breakdown, improve recovery from intense exercise, and support lean muscle mass gains, particularly in untrained individuals or during periods of high stress.

Key Benefits

Faster Absorption

HMB-FA is absorbed more quickly and has higher bioavailability than the standard calcium-salt form (HMB-Ca).

Reduces Muscle Breakdown

Acts as an anti-catabolic agent, minimizing muscle protein breakdown during and after intense training.

Enhances Recovery

May lead to reduced markers of muscle damage, such as creatine kinase, and less perceived muscle soreness.

Supports Lean Mass

Some studies suggest it can help increase lean body mass and strength, especially when combined with resistance training.

Dosage & How to Take

The typical dosage is 1 gram taken up to three times per day.

PurposeDoseNotes
Pre-Workout1,000 mgTake 30-60 minutes before training to maximize plasma concentrations during exercise.
General Anti-Catabolic Support1,000 mg, 3 times dailySpread throughout the day to maintain elevated HMB levels.

Best Time to Take

Best taken on an empty stomach before workouts. Can be taken with meals on non-training days.

With or Without Food

Can be taken with or without food, but pre-workout absorption is faster on an empty stomach.

Forms & Bioavailability

FormAbsorptionBest ForNotes
Free Acid (HMB-FA)Very HighRapid pre-workout absorption.Typically found in a liquid or gel capsule form.
Calcium Salt (HMB-Ca)HighGeneral daily use, more cost-effective.The most common and well-researched form.

Side Effects & Safety

Common

  • Generally well-tolerated with no common side effects reported at standard doses.

Rare

  • No significant rare side effects have been consistently reported.

Contraindications

  • Should be avoided by pregnant or breastfeeding women due to a lack of research.

Interactions

Scientific Research

2014Journal of Strength and Conditioning Research

Effects of a 12-week HMB-FA and ATP supplementation on muscle mass, strength, and power in resistance-trained individuals

Supplementation with HMB-FA and ATP led to significant increases in strength and lean body mass compared to placebo.

Food Sources

Small amounts are found in catfish, alfalfa, and grapefruit.

Frequently Asked Questions

Medical Disclaimer

This content is for educational and informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare professional before starting any supplement regimen, especially if you have pre-existing health conditions or are taking medications. The statements on this page have not been evaluated by the Food and Drug Administration.