HMB might promote muscle growth. It seems to reduce the destructive breakdown of muscle
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.
HMB, currently, appears to be a pretty interesting supplement for the purpose of reducing muscle wasting during periods where muscle atrophy is accelerated 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).
(Effective= 10/10) (Can be Effective 9/10) (Insufficient Evidence 8/10)
Age related muscle loss. Most research shows that taking HMB can slightly decrease the loss of muscle associated with aging (9/10)
High cholesterol. Early research suggests that HMB can lower cholesterol (8/10)
High blood pressure. Early research suggests that HMB can lower blood pressure (8/10)
Muscle strength. Most research shows that HMB helps increase muscle a little in people who are just beginning to train but not in well-trained athletes (8/10)
Disease-related weight loss (cachexia) (8/10)
Foot ulcers from diabetes (8/10)
Skin rash from radiation therapy for cancer (8/10)
Diseases of the heart and blood vessels (cardiovascular disease) (8/10)
HMB is POSSIBLY SAFE for most people when taken by mouth, short-term. Doses of 3 grams per day or less for up to one year seem to be safe.
Special Precautions & Warnings:
Pregnancy and breast-feeding: There is not enough reliable information about the safety of taking HMB if you are pregnant or breast-feeding. Stay on the safe side and avoid use.
Beta-hydroxy-beta-methylbutyrate, B-Hydroxy B-Methylbutyrate Monohydreate, Beta-Hydroxy-Beta-Methylbutyric Acid, Calcium B-Hydroxy B-Methylbutyrate Monohydrate, Calcium HMB, Hidroximetilbutirato, HMB, HMB de Calcium, Hydroxyméthylbutyrate, Hydroxymethyl Butyrate, Hydroxyméthyl Butyrate.<br/><br/> source: webmd & examine.com