Ultimate Guide on Fat Burners

The term Fat Burners is used to refer to all dietary supplements that increases fat metabolism or energy expenditure, reduce the absorption of lipids or carbohydrates from food, increase weight loss, increases the oxidation of fats during physical exercise, or anything else that in the more or less causes an increase in lipolysis, a decrease in appetite or a limitation of the absorption of fats.

The most popular fat burning supplements are caffeine, carnitine, green tea, conjugated linoleic acid, forskline, and taurine. The lesser known ones are ephedrine from the ephedra plant, capsaicin which decreases appetite, and clenbuterol. In this article, we will discuss different types of fat burners in relation to their mechanism.

The different types of fat burners


Thermogenics are supplements that will basically help burn fat. They are effective in dislodging stubborn fat stored in adipose tissue. The energy resulting from thermogenesis can be used to perform muscle work or to increase the internal temperature of the body. Caffeine is the most popular supplement in this category. Yohimbine is also very popular across the Atlantic despite a relatively low number of scientific studies on it.


Caffeine, ephedrine, and ephedra are stimulating ingredients prevalent in most fat burners. In United States, ephedrine and ephedra are banned. Although they are sold over the counter in some countries, these substances are banned by the International Olympic Committee (IOC).

These stimulants which increase vigilance exhibit side effects for some such as: nervousness, palpitations of the heart, digestive problems.

Carbohydrate Blockers

Carbohydrate blockers contain ingredients that prevent the functioning of certain digestive enzymes. The one's which function to break down carbohydrates into simple sugar. As a result, the carbohydrates you eat are no longer assimilated because of their “large” size. Calorie intake and insulin secretion are also reduced.

These blockers contain white bean extract which contains a substance that reduces digestion and therefore absorption of starch. This means that if you gorge on sweets or other sources of simple sugars, these supplements will have no effect. Carb Blockers work well with foods such as bread, potatoes, pasta, etc.

The main disadvantage of carbohydrate blockers is the production of gas in large quantities causing bloating and abdominal pain. This is because the bacteria present in the colon ferment the excess carbohydrates.

Another side effect: the drop in blood sugar and therefore the drop in energy which can lead to discomfort.

For these reasons, it is highly recommended to seek advice of a doctor before taking this type of supplements or medication.

Also read: White Sugar: A Death Sentence

Lipid Blockers

Same principle as the blockers of carbohydrates, but this time, it is the lipids assimilation which is limited. One of the main ingredients in these fat blockers is chitosan (also found as chitosan).

Chitosan has the ability to chemically bind to lipids, up to 15 times its own weight. As this macromolecule cannot be metabolized, lipids are not assimilated by the body: they are therefore excreted in the stool.

There is also a drug (Orlistat) marketed under the brand Xenical from Roche or Alli from GlaxoSmithKline (banned recently). Orlistat inhibits the enzymes in the intestines called lipases, the job of which is to break down fat.

The problem with these fat blockers is that they also prevent the absorption of fat soluble vitamins that the body needs to stay healthy.

Thyroid Regulators

The thyroid is an endocrine gland located in the neck that regulates, among other things, basic metabolism. Its function is to control the way the body burns energy and makes protein. This organ also helps regulate the body's sensitivity to other hormones.

If your thyroid gland is not functioning optimally, it will no longer secrete enough hormones and your metabolism will slow down. To avoid this, there are thyroid stimulators which can boost the metabolism and therefore help to lose weight.

Among the ingredients to boost the thyroid are iodine and plant extracts such as commiphora mukul, chondrus crispus and laminaria digitata.

Appetite Suppressants

Appetite suppressants are substances (supplements or drugs) that reduce appetite and allows you to eat less.

Like all other types of fat burning medication don't use without a doctor's advice. You may have heard of Meridia, the weight loss pill for treating obesity. This slimming drug which can be bought from underground sellers was withdrawn in 2010 following numerous heart and stroke related incidents caused by the active substance, sibutramine.

Among the supplements that help stop food cravings, hoodia gordonii is a very popular plant. Unfortunately, this plant known to be a natural appetite suppressant, used for hundreds of years by the indigenous populations of South Africa. Its illicit use is not authorized in many major countries of the world.

If you're looking for natural, side-effect free appetite suppressants, look for high-fiber, low energy foods.

Also read: Top 10 Foods to BUILD MUSCLES

Cortisol Blockers

Cortisol is a hormone released by the adrenal glands. This hormone is often referred to as the “stress hormone” which increases blood pressure, blood sugar levels and weakens the immune system.

When cortisol increases, appetite and fat storage increase. In other words, whenever we are under stress, cortisol increases in the body, and tells our brain that we are hungry, while activating the storage of triglycerides in the adipocytes. Cortisol blockers can prevent these negative side effects.

The fat-burning ingredients


Also called “theine”, “guaranine” or even “mateine”, caffeine acts as a stimulant and increases the release of adrenaline and norepinephrine in the body.

These neurotransmitters or vigilance hormones accelerate the breakdown and combustion of fatty acids, making them available as sources of fuel. Caffeine also acts as a mild appetite suppressant.

All the information on the effects of caffeine on the metabolism comes from physiological studies carried out in the 70s. The first studies showed that the caffeine ingested before physical exercise significantly increases the rate of fat oxidation, thus performance.

This mechanism occurs indirectly by increasing the circulating level of adrenaline (which has the potential to improve the availability of fatty acids for oxidation).

Caffeine also provides a short-term thermogenic effect caused by increased oxidation of fats.

Be careful, by consuming caffeine regularly, you decrease your sensitivity to this stimulant, and over time, these benefits become unnoticeable.

The interest of consuming one or two espressos before each workout is therefore debatable: we must not deny the placebo effect either.

In absolute terms, it is better to consume caffeine cyclically to get the most of these benefits.

Plants Containing Caffeine

  • Guarana: this Amazonian plant contains the highest concentrations of caffeine, between 3.5 and 5.8% of its volume. In comparison, coffee has a maximum of 2%.
  • Tea: tea leaves (camellia sinensis) allows the preparation of the most consumed drink in the world after water. This makes it the most popular thermogenic for weight loss. The caffeine in tea represents between 2.5 to 5% depending on the variety. Green tea also contains a powerful antioxidant, epigallocatechin gallate (EGCG), a polyphenol beneficial for health.
  • Yerba mate: A popular South American herb that has a caffeine concentration between that of coffee and that of tea leaves.
  • Coffee: native to East Africa, the coffee tree is a shrub mainly used for its caffeine. This green coffee is much richer in antioxidants.
  • Cocoa: these beans are used to make chocolate. 100 g of dark chocolate is equivalent to the amount of caffeine contained in an espresso (43 mg).
  • Cola nuts: a traditional source of caffeine in African countries, its caffeine content is slightly higher than that of coffee.

Cayenne Pepper

Cayenne Pepper contains capsaicin, a powerful antioxidant that activates heat receptors in the skin, hence the burning sensation. But that's not all. Several studies have shown that capsaicin increases energy expenditure which results in more fat burned. This increase in fat metabolism is due to a significant secretion of adrenaline and norepinephrine, generated by capsaicin.

If you are sensitive to anything spicy, you can buy cayenne pepper extract as a dietary supplement.

Be careful, capsaicin can cause heartburn. Start with small amounts to test your tolerance.

Neither cooking, drying or freezing can overcome capsaicin. There is only one protein that you probably know that can neutralize it, and it is casein, a protein in milk. If you are doing a Chili Challenge, do not drink water to put the fire out, but rather use dairy products such as milk, cheese, yogurt or a casein shake!


This essential fatty acid belonging to the omega-6 family and is one of the healthiest dietary supplements. It has many positive effects on energy metabolism, adipogenesis, inflammation, lipid metabolism and on adipocyte apoptosis (fat cell death).


This essential trace element helps metabolize carbohydrates and fats. It is currently center of attention of huge media and marketing hype. Chromium helps the body build muscle, promote fat loss, and reduce appetite.

It is marketed mainly in the form of chromium picolinate, chromium nicotinate, or chromium chloride. Picolinic acid is an organic compound that binds to chromium and promotes its absorption and transport.

Be careful to never exceed the recommended dosage. A study carried out in 1995 suggested that an excess of chromium can cause chromosomal damage, in other words cancer.


Carnitine is a molecule produced in the body that is found naturally in meat, fish, and dairy products. This compound is involved in the transport of long chain fatty acids across the inner mitochondrial membrane.

Carnitine supplementation helps improve fat metabolism, reduce fat mass and increase muscle mass. This supplement is also used by endurance athletes to increase fat oxidation and therefore performance.


Active ingredient of the coleus forskohlii plant, forskolin stimulates an enzyme (lipase), which hydrolyzes the triglycerides stored in the adipocytes. This ingredient is present in many supplements used for drying/cutting, including the famous Hydroxycut Hardcore from MuscleTech or Animal Cuts from Universal Nutrition.

Cider Vinegar

Apple cider vinegar (ACV for Apple cider vinegar) is a natural remedy, used by many as a preventive measure rather than a cure.

The most interesting study on how apple cider vinegar helps you lose weight was published in 2009. Published in the journal Bioscience, Biotechnology, and Biochemistry, the study concluded that drinking 2 tablespoons of vinegar for 2 months can help with weight loss, especially belly fat, which leads to waist reduction.

Regarding its mechanisms of action, we now know from numerous studies that it acts as an appetite suppressant and improves insulin sensitivity.

Controversial or banned fat burners


A popular ingredient in bodybuilding before the 2000s, especially in the form of ECA Stack (ephedrine, caffeine, aspirin), this Chinese herb called ma huang or ephedra is banned in many countries including United States. This stimulant of the central nervous system, cardiovascular system, respiratory system, and the digestive and urinary sphincters causes many side effects, such as heart attacks and strokes.

Bitter Orange

Bitter orange peel is one of the most effective fat-burning foods for reducing body fat. It contains synephrine, a compound chemically similar to ephedra. While this thermogenic herb can help promote weight loss, it can also contribute to heart diseases and other serious health issues.

Garcinia Cambogia

Also known as Malabar Tamarind, this little berry can suppress appetite and boost metabolism. However, these effects were not seen in all studies. Even though garcinia cambogia helps reduce the buildup of abdominal fat, it also comes with its share of side effects. We'll do a separate article on it soon.


The Clenbuterol is one of the most powerful (and most dangerous) thermogenic. Used in bodybuilding to increase muscle definition, its consumption causes, among other things, tremors, hyperhidrosis (excessive sweating), cardiac arrhythmias and muscle cramps.

Fat Burners FAQs

Do Fat Burners Really Work?

Yes, fat burners can actually help with fat loss, but with the condition that you are following a proper diet. They are a “supplement”, not a miracle. If you eat more calories than you need, nothing can help you lose weight.

When to take a fat burner?

The best time is in the morning when you wake up, especially for thermogenics and stimulants like caffeine. These can also be taken 30 minutes before workout, unless you are training at the end of the day. In this case, take them only in the morning if you are looking get a good sleep.