- 1 Thomson википедия
- 1.1 Summary of HMB
- 1.2 Things to Know
- 1.3 How to Take
- 1.4 Frequently Asked Questions
- 1.5 Human Effect Matrix
- 1.6 Scientific Research
- 1.7 1 Source and Structure
HMB is an active metabolite of leucine that reduces muscle protein breakdown. It appears to have an anticatabolic role for muscle, but fails to be more effective than its parent amino acid for inducing muscle protein synthesis.
This page features 71 unique references to scientific papers.
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Summary of HMB
Primary Information, Benefits, Effects, and Important Facts
HMB (short for β-Hydroxy β-Methylbutyrate) is a metabolite of the amino acid leucine that, along with KIC (α keto-isocaproate) and isovaleryl-CoA, mediate the effects of leucine. Approximately 5% of dietary leucine is oxidized into HMB, and HMB appears to be the main metabolite of leucine that more effectively prevents the breakdown of muscle protein.
When compared to leucine, HMB appears to be significantly more potent on a gram per gram basis at attenuating the rate of muscle protein breakdown but is less effective than leucine at inducing muscle protein synthesis. Due to this, HMB is marketed as an anti-catabolic agent (purposed to reduce the rate of muscle breakdown) rather than an anabolic agent (purposed to increase muscle mass).
Human trials don’t normally tend to be structured to properly assess the effects of HMB, as most of the studies are a standard diet paired with an exercise regimen investigating the role of HMB in promoting muscle protein synthesis (of which it is similar to leucine in the sense that there are positive results, but quite unreliably so), the limited evidence that assesses HMB during periods of muscle loss are either underpowered or not in athletes.
HMB, currently, appears to be a pretty interesting supplement for the purpose of reducing muscle wasting during periods where muscle atrophy is accelerated (cachexia, AIDS, bedrest) and should theoretically work in athletes on a calorie restricted diet but is not fully established for this role yet (which is a notable issue, since glutamine has a large dichotomy between clinical and healthy populations).
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Things to Know
Also Known As
Do Not Confuse With
Leucine (parent amino acid)
Is a Form Of
How to Take
Recommended dosage, active amounts, other details
Supplementation of HMB tends to be in the dosage range of 1-3g daily for the purpose of reducing muscle mass losses over time (anti-catabolic). As HMB is said to be 20-fold more potent than leucine for this purpose, it is seen as equivalent to 20-60g of leucine supplementation.
For the purpose of muscle protein synthesis, HMB and leucine are fairly equivalent if not the latter (leucine) being more potent on a gram basis. HMB is not advised for inducing muscle protein synthesis since leucine is likely more effective as well as cheaper.
Supplementation of HMB prior to an exercise session would require the usage of an HMB free acid rather than a calcium salt, and the above dosage range still holds. For this specific purpose, HMB is to be taken 30-45 minutes before a workout.
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Frequently Asked Questions
Questions and answers regarding HMB
Q: Four Testosterone Boosters and Sketchy Research
Human Effect Matrix
The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what effects hmb has on your body, and how strong these effects are.
Studies Excluded from Consideration
Confounded with Arginine and Lysine, and one with Vitamin D   
Confounded with other amino acids 
Table of Contents:
- 1 Source and Structure
- 1.1 Sources and Biosynthesis
- 1.2 Supplemental Sources
- 2 Longevity and Aging
- 2.1 Muscle Mass
- 3 Skeletal Muscle and Exercise
- 3.1 Mechanisms
- 3.2 Bioenergetics
- 3.3 Power Output
- 3.4 Muscle Damage
- 3.5 Muscle Protein Synthesis
- 3.6 Muscle Atrophy/Catabolism
- 4 Fat Mass and Obesity
- 4.1 Appetite
- 4.2 Interventions
- 5 Interactions with Glucose Metabolism
- 5.1 Insulin
- 5.2 Interventions
- 6 Immunology and Inflammation
- 6.1 Interventions
- 7 Interactions with Hormones
- 7.1 Testosterone
- 7.2 Cortisol
- 7.3 Growth Hormone
- 8 Nutrient-Nutrient Interactions
- 8.1 Creatine
- 9 Safety and Toxicology
- 9.1 General
1 Source and Structure
1.1. Sources and Biosynthesis
HMB is an acronym for HydroxyMethylButyrate,