TL;DR Summary: Does HMB Burn Fat?
HMB may assist in accelerating the loss of body fat, but HMB does not burn fat itself. Exercise-induced muscle protein breakdown appears to decrease with HMB supplementation. This in turn forces the body to turn to stored fat for fuel rather than muscle protein. Plus, having more lean muscle tissue raises your metabolic rate, further helping you burn fat.
HMB is a phenomenal fat burner ingredient, and a superb supplement in its own right. Many of the best vegan fat burners on the market today use HMB as a main ingredient; Burn Lab Pro, our top rated fat burner, uses it as a main ingredient because it is so reliably effective and safe.
So while this far from the most popular supplement in the gym right now, in the future HMB is almost certainly going to become a staple sports performance supplement among bodybuilders, strength athletes, competitive fighters, and more.
But until we reach that point, there is very little information available about what HMB is actually capable of doing.
Because HMB is so poorly understood by the average person, misinformation spreads online like wildfire.
One thing we constantly see being confused on bodybuilding forums is HMB’s status as a fat burner. Many people claim that HMB burns fat. They assume that because it is in a high quality fat burner, HMB must cause or support fat loss in some way.
HMB may be a great ingredient to have in a fat burner, but does it burn fat?
In this article, we’ll explain what HMB is, what it does, and how it works. We will explain why HMB is a great ingredient in a fat burner even though it does not actually promote fat loss directly.
What Does HMB Do?
As stated above, HMB is potentially one of the best supplements you can use if you are a serious athlete.
The reason HMB is so beneficial for athletes (and for pretty much anybody really) is because it has a totally unique effect that you cannot replicate with any other natural substances.
Simply put, HMB prevents muscle mass loss.
It might sound too good to be true, but it is; HMB effectively prevents muscle mass loss.
Amazingly, HMB seems to prevent muscle tissue catabolism in people in a severely calorie restricted or even fasted state! That means you can do intensive weight training while fasting and not worry at all about muscle tissue loss.
We don’t need to tell you that this is pretty incredible. Generally, muscle catabolism is at its most aggressive when you are training in a fasted state. If HMB can actually protect muscle tissue while you train in a fasted state, then it achieves something that you could previously only do with performance enhancing drugs.
This is why HMB is so beneficial for bodybuilders, strength athletes, MMA fighters, and any other athletes who need to retain muscle mass while cutting weight.
Cutting weight usually means accounting for significant muscle mass loss. HMB prevents muscle mass loss, meaning athletes can follow more aggressive cuts while keeping their strong, powerful, aesthetic physiques.
How Does HMB Work?
So how does HMB work then?
How can a natural supplement like HMB possibly prevent muscle tissue catabolism?
There is some disagreement over how HMB actually works. There is some solid clinical evidence to support several different theories about how HMB works. It is likely that it actually works via a number of different mechanisms.
Of these, the main mechanism of action of HMB is almost certainly that it prevents muscle protein breakdown by inhibiting bodies called proteasomes.
Proteasomes are bundles of proteins which are responsible for destroying proteins in the body that are deemed old, broken, damaged, or no longer needed. This is a normal process vital for overall health. But if your goal is to maximize muscle mass while minimizing fat loss, then this sort of protein breakdown is the opposite of what you want.
HMB seems to inhibit the activity of proteasomes, specifically two proteasomes which are highly active in breaking down muscle tissue protein. In doing so, it effectively block muscle tissue protein breakdown (proteolysis).
Does HMB Cause Fat Loss?
So does HMB burn fat?
No, HMB does not burn fat. Although HMB is a common ingredient in high quality fat burner supplements, it is not actually a fat burner itself.
At least not directly.
As explained above, HMB preserves muscle mass during periods of caloric restriction, fasting, and intensive training. It works by preventing muscle protein breakdown, which is normally rampant while training in a fasted or low-calorie state. HMB does not stimulate the mobilization of fat from fat stores, it does not suppress appetite, and it does not increase metabolism.
How Does HMB Help With Fat Loss?
So how does HMB help with fat loss if it doesn’t burn fat?
HMB helps with fat loss indirectly by both increasing lean muscle mass and by raising your resting metabolic rate.
In other words, HMB helps with body composition and muscle mass gains, both of which in turn accelerate fat loss and promote a lean, muscular physique.
So by improving your body composition, increasing the ratio of lean mass to body fat, HMB indirectly speeds up fat loss.
Having more muscle mass ultimately speeds up your metabolism and encourages the burning of fat. It also increases your resting metabolic rate, which makes fat loss even easier as it becomes easier to enter a caloric deficit.
- HMB Side Effects: Is it dangerous?
- Does HMB Burn Fat?
- How much HMB should you take per day?
- Should you take HMB every day?
- When to take HMB for best results
Pavel Sadovnik is a leading biochemical scientist with a PhD in biochemical engineering. He has spent decades working in industry as a chemist and pjharmaceutical consultant. He has extensive experience with the supplement industry, and specialises in supplement tsting and formulation consultancy. He is the Editor of NARSTO.