When it comes to building size and strength, bodybuilders are willing to try just about any supplement that offers even a slim hope of helping them reach their goals. HMB, or beta-hydroxy-beta-methylbutyrate, is one of just a few compounds that is backed by actual scientific research, and it seems to be effective for most lifters. But is HMB really safe for you to take?
That’s a question you should ask about any supplement you are considering, and it’s a tough one to answer in many cases.
Luckily, HMB has been studied extensively enough that we can get a pretty good idea of possible side effects by parsing through the literature.
What Is HMB?
To begin understanding possible side effects of HMB in the body, we need to know what it is.
Leucine is one of three branched-chain amino acids — along with isoleucine and valine — that are also essential, meaning that your body requires them but cannot manufacture them from other subances. You must consume the BCAAs in the food you eat.
Good sources of leucine include egg whites, poultry, fish, and grain-fed meats.
Leucine plays an important role in the energy cycle of your muscle cells, and it is also necessary for protein synthesis, or the creation of new protein. In both of these reactions — energy and protein production — leucine is broken down into a series of metabolites.
HMB is one of those byproducts.
On the surface, then, HMB in your body is a natural consequence of the processes necessary for life — eating, energy production, protein synthesis. You might think it would pose little or NO risk to you, but the game can change when we start talking about larger amounts of any compound.
In particular, while your body produces on the order or half a gram of HMB per day, studies have found that we require 3-9 grams daily to achieve muscle-growth benefits.
Are those doses safe?
What the Experts Say
The good news is that most trusted sources have found very few side effects when it comes to HMB supplementation.
WebMD, for instance, rates HMB as “possibly safe” for most people taking three grams or less per day for up to eight weeks. That may not seem like a ringing endorsement, but WebMD does not mind calling out supplements as unsafe if they perceive any real danger. It should be noted that they DO caution against the use of HMB for pregnant and breast-feeding women.
Search for fitness and bodybuilding links online and you will find the top websites and forums, too, report that there have been very few incidents of side effects for lifters taking HMB.
Meanwhile, nearly all of the available research studies have reported no significant side effects of HMB supplementation. A 2008 literature review, for example, found that HMB contributed to strength and muscle gains across wide subject populations, but no adverse effects when they supplemented with 3-6 grams per day for the duration of the studies.
Seek a Professional Opinion
So, can you take HMB without concern for side effects?
That’s hardly ever a wise course of action, and it would certainly be prudent to exercise caution when supplementing with HMB. While studies have not revealed serious side effects, most of the trials have been conducted for 12 weeks or less, and discovering side effects was not the main focus of the researchers involved.
More long-term studies will be needed to conclude that HMB is safe for everyone all the time, and it’s likely SOME undesirable side effects will surface down the road.
The safest thing to do, as always, is to talk with your doctor about HMB and how it might affect your health. He should be able to help you figure out if HMB will cause you any troubles, given your current situation and medical conditions (if any).
For the most part, though, and until we learn more, HMB appears to be both safe and effective for the majority of lifters.