Total Shape is a reader-supported site. Purchases made through links may earn a commission. Learn more.

How Does Clenbuterol Burn Fat? (According to Science)

Isaac Robertson
Published by Isaac Robertson
Fact checked by Donald Christman, BHSc FACT CHECKED
Last updated: March 27, 2023
We personally test every product featured in our reviews and guides. By ordering products anonymously and getting a group of independent testers, we are able to get first-hand experience and provide data-driven recommendations. Learn more.

If you spend enough time at the gym, you’ll inevitably hear people talk about anabolic steroids and substances like Clenbuterol.

Clenbuterol has gained a lot of attention in recent years for its supposed ability to help with body fat loss while preserving lean muscle mass at the same time.

While there is some evidence that it helps bodybuilders in cutting phases, the question is how it targets fat reserves and what the safety concerns are.

We teamed up with a dietitian and nutritionist to find out what’s behind it all.

Quick Summary

  • Clenbuterol burns fat in two main ways, namely epinephrine receptor binding, and speeding up an individual's metabolism rate.
  • Some people use Clenbuterol to increase their lean muscle mass, and muscle protein synthesis for recovery.
  • Clenbuterol can be consumed as a pill, liquid, or nasal spray.

What Does Clenbuterol Do For Fat Metabolism?

a person's hand filled with white pills and another with pill bottle

It was not intended for Clenbuterol to improve performance or serve as a fat burner.

It was designed for treating horses with breathing disorders.

During animal trials, scientists figured out that it was also targeting metabolic processes.

And the effect on fat happens in two ways.

1. Epinephrine Receptor Binding

Clenbuterol targets the same receptors that react to the hormone epinephrine. And while this is a completely natural process in the human body, Clenbuterol does so much more effectively.

Studies have shown that this may trick the body into burning off more flabby stuff, even at a relatively low dosage [1].

The big question is whether this is a safe way to reduce your BMI and what else it might do to your body.

More on this shortly.

2. Boosted Base Metabolic Rate

woman smiling while resting her hands on her stomach

Proponents of it say that it also boosts your metabolic rate even when you're at rest.

That makes it sound like athletes can use Clenbuterol as a magic pill to get rid of excess fatty tissue.

Unfortunately, there are neither human nor animal trials that can confirm this effect, so I would guess it is a purely speculative effect that might be based on minimal anecdotal evidence.

Does Clenbuterol Have Other Uses?

woman smiling while holding up a kettlebell and her arms, and a man placing a pill in his mouth

Clenbuterol made it into the circles of professional bodybuilders and athletes even though the FDA never cleared it.

While it’s not illegal to own or take, the main reason it hasn’t been cleared as an official drug is that it can cause heart damage.

We’ll cover that shortly.

Beyond using it as medication for horses, some bodybuilders have used it for two other reasons.

1. Muscle Protein Synthesis For Recovery

The same study mentioned above that showed the use of Clenbuterol was linked to fat metabolism also identified that it binds to muscle cells.

It triggers an increased level of protein synthesis; in other words, it speeds up muscle repair.

Your muscles endure microscopic tears during every training session, and an increased protein synthesis means that you should feel less sore afterward.

It’s something bodybuilders always try to maximize, but maybe the body has limits for a good reason.

2. Increase Lean Muscle Mass

shirtless man's chest and arms

The problem athletes face when they need to bulk up is that the excess calorie intake required also contributes to an increase in BMI.

It’s the dreaded effect of bigger muscles hidden underneath some flabby tissue.

Some people take this substance because they believe it will help them maintain or even grow more muscle mass while helping to get rid of fat at the same time.

While some users may have experienced this, it has not been proven through scientific studies, and it ignores the risks of targeting such abnormal processes in the first place.

How Do You Take Clenbuterol?

People have been taking Clenbuterol for many years, and initially, it was only available in the form of pills, like many other sports supplement products.

But during our research, we did find a few companies that have made different options available to make it easier to fine-tune the dose.

One such option is a liquid form, and you can measure the intake in small drops.

We also found a nasal spray, but it may be difficult to get an exact dosage with this option.

Does Clenbuterol Have Side Effects?

woman having a headache and a man holding his painful nape

Yes, Clenbuterol use comes with a long list of negative effects, and some of them can be very serious.

The most common one you hear is increased blood pressure, but most people don’t realize that this could be the result of cardiac hypertrophy, which is an abnormal enlargement of the heart [2].

Other things that could happen to you include:

  • Muscle cramps
  • Feeling faint
  • Chest pain
  • Trouble sleeping
  • Excessive sweating
  • High blood pressure
  • Tremors
  • Nausea
  • Headaches

With prolonged use and higher doses, all these negative effects could lead to a heart attack and even death.

The issues mentioned above should be enough to convince you that it is not the risk-free drug for cutting that some people at the gym may have argued.

Even if some people you know didn’t experience any side effects, there are probably better and safer options you should consider, especially ones that haven’t been banned.

Are There Better Fat Burning Alternatives?

preworkout supplements in a blue background, and different pills in bowls

If you’re heading for a cutting phase as a bodybuilder or performance athlete, there are much better and safer fat-burning supplements that are prescription-free.

Here’s what we recommend to our clients.

1. Thermogenic Fat Burner

There are plenty of weight loss products based on natural ingredients that have been scientifically proven to help trigger thermogenesis.

It is a metabolic process that raises your core body temperature by a few degrees. It burns off more calories in the process, and the result should be a reduction in your BMI.

2. Pre-Workout Supplement

Training a little bit harder during your workouts is one of the best ways to get the results you want to achieve.

With a natural pre-workout, you should be able to reduce your fatigue and improve your strength by a few percentage points.

That adds up over time and might help you speed up your cutting phases.


Do You Lose Muscle on Clenbuterol?

No, you don’t lose muscle on Clenbuterol. It may improve muscle tissue repair and development. However, it’s unclear how much effect it can have on your muscles compared to safer options.

Will Clenbuterol Fail a Work Drug Test?

No, Clenbuterol won’t cause you to fail a work drug test as it’s not an illegal drug. Testing positive for a drug screening would only happen when illegal substances were detected.

Is Clenbuterol Illegal?

No, Clenbuterol is not illegal, but it’s also not approved by the Food and Drug Administration as an ingredient for any therapeutic drug. And the World Anti-Doping Agency and International Olympic Committee have listed it as a banned performance-enhancing drug.

How Long Do Clenbuterol Effects Last?

Clenbuterol effects can last for up to 6 days, but it may take even longer to wash out all the traces out of your system.

Should You Consider Clenbuterol For Weight Loss?

We don’t recommend that you use Clenbuterol because of the serious potential negative effects.

With the above-mentioned alternatives, you can maintain lean mass and still manage to lose weight.

If you’ve had experience with it or know of some other resources we should include, please leave a comment below or reach out to us on social media.


Was this article helpful?

About The Author

You May Also Like

Write a Reply or Comment

Your email address will not be published. Required fields are marked *