What Are Thermogenic Supplements? How Do They Work?

Have you heard all about thermogenic ingredients? They’re the metabolism boosting plant extracts and compounds everybody keeps talking about. Science says they can speed up your calorie burn, and some studies show their benefits for fat loss.

But, how do they work? And should you be taking them? Read on to find out.

What is thermogenesis?

Thermogenesis is the process your body uses to produce heat. It’s something that happens in warm blooded animals, which as you’re human, applies to you. In fact, one of the key roles of your metabolism is to generate this heat to keep you alive. When you create this heat and raise your core temperature, you’re burning calories like firewood.

Now, your body can handle temperature increases of around five degrees and drops of ten. There’s also a part of your brain called the hypothalamus, which works to help thermoregulation – aka control your body temperature. Get too cold? You’ll shiver. How about too hot? Well, that’s when you start to sweat, so you can cool down.

However, it’s not just external physical changes that can alter your body temperature. There’s also a thing called the thermic effect of food, meaning what you eat can also influence thermogenesis. Some of these foods are called thermogenic supplements.

What are thermogenic supplements?

Thermogenic supplements contain certain compounds that are selected because of their ability to cause thermogenesis. More specifically, they’re able cause a shift in your temperature, and therefore your resting metabolic rate (RMR).

RMR is the number of calories you burn while you’re resting. So, the ingredients inside thermogenic supplements should boost your calorie burn, without you even needing to exercise. Yes, that’s extra calories used throughout the day, without any extra effort.

Depending on which thermogenic supplement you look at, some might offer help increasing fat oxidation too. There are also appetite suppressants added at times too, which are there to help users cut back their cravings and hunger.

One thing to remember though, is that thermogenic supplements aren’t magic pills or potions. Effective fat loss can only happen through hard work and making sure you stick to a calorie deficit. That’s when you eat less calories than you burn in a day or week.

What thermogenic supplements can do however, is step up your efforts. Exercising regularly and eating a wholesome, healthy diet should be your priority. The thermogenics should give you a few extra calories burned and reduce nagging cravings.

Some thermogenic supplements might just be single ingredients like caffeine. Others could contain up to double figures in fat loss extracts and compounds. There’s no set formula, but there are a bunch of well-researched and popular ingredients.

Thermogenic ingredients - what are thermogenic supplements

Who should take thermogenic supplements?

So, now you know all about thermogenic supplements, you’re probably wondering who should take them? If so, keep reading, because we’re about to find out.

Thermogenic supplements are for those who want to add a little extra support to their fat loss attempts. You could be dieting properly and just want a way to slightly increase your energy expenditure. On the other hand, you might be really into fitness and would like help to stay energized while your food portions are smaller.

As you can guess, the range of thermogenic users can be really broad. However, it’s those with the desire to work hard and dedication to that all important calories deficit that get the best results. Monitoring food and being a good, honest dieter is an absolute must! You can still enjoy the odd sweet treat, so long as it’s part of your plan.

Thermogenic supplements aren’t for anyone who isn’t prepared to take responsibility of their diet or exercise. If you’re not in a calorie deficit, where you burn more calories than you eat, no legal supplement will work. It’s the honest science of safe body fat loss.

Common fat-burning ingredients

As you’d expect, some ingredients stand out as being favorites for their fat burning effects. There’s the likes of caffeine and other stimulants that indirectly boost metabolism, while compounds like capsaicin are alternatively known as pure thermogenics.

To help you separate the best from the rest, let’s look at the most common fat-burning ingredients out there. Here’s what to expect.


When we think about caffeine, we usually conjure up images of coffee cups and tea. Yet, this natural stimulant is actually found in over 60 various plants. Besides coffee beans and tea, the likes of cocoa, guarana, and yerba mate are all caffeinated plant sources.

Caffeine releases the hormone adrenaline, which then causes fat cells to release fatty acids into the blood (1). These fatty acids can then be used to energize your body.

However, the reported fat burning benefits don’t end here. You might also find that caffeine increases your metabolism as well as helps curb appetite (1). As a result, you should be able to boost your daily calorie burn, while at the same time not eating as much food.

According to current research, 3-5 mg/kg of body weight is the best dose to ramp up your metabolism (1).

Caffeine risks & side effects

It’s important to remember caffeine is a stimulant, which means you should be careful when using it. Follow manufacturer guidelines and try not to take it within five hours of going to bed.

Not only that, but if you’re no longer caffeine naïve, the effects will be dampened. The fix? Try not to overuse caffeine so you’re still sensitive to it.


Ever eaten something hot and felt the onset of spice-induced sweats? You have capsaicin to thank for that. Put simply, you shouldn’t feel as hungry, or crave as much food.

Capsaicin is the active compound that gives chilis their fiery taste. As you can guess; the hotter the pepper, the more capsaicin is in it.

This taste bud tingling extract is one of the most common ingredients inside thermogenic supplements. It also works like caffeine, because when you eat it, your body releases adrenaline, which boosts your metabolism (2).

Capsaicin is also similar to caffeine in that it suppresses appetite. Eating is said to benefit your weight loss journey, as it can help you reduce your daily energy intake (3).

But what if you can’t stomach spice and even mild is too hot to handle? Fear not. Capsaicin is usually always included inside capsules, so it never even touches your tongue. You shouldn’t taste a thing when taking it.


Okay, so technically, this soluble fiber isn’t actually a fat burner. It doesn’t boost metabolism, increase fat oxidation, and it doesn’t magically banish belly fat.

So, why include it? Because glucomannan, also known as Konjac root fiber, is one of the most proven methods of calming hunger. It’s also one of the best at absorbing water, and you don’t actually digest it either. The latter makes it very low-cal.

Glucomannan is said to benefit fat burning by expanding inside your stomach and providing sensations of fullness. The fiber also slows stomach emptying.

When taken before food, glucomannan apparently helps control portion sizes and allows you to feel fuller for longer after eating. Of course, this should make it easier to manage daily calories (4).

Plus, because it’s a soluble fiber, glucomannan can reduce the abruption of fats (5). While it’s not technically a fat burner, we still think it should be included because of how popular it is in thermogenic supplements.

Green Tea

You may have seen green tea touted as a single ingredient thermogenic or as part of a broader fat burning product. But what exactly does the bitter drink have to offer?

Besides a whole strain of health benefits, it has a distinct double approach to boosting metabolism. Green tea offers not one, but two thermogenic compounds; caffeine and EGCG (epigallocatechin).

We talked about caffeine earlier and saw its ability to speed up your metabolism. We also discovered how it can calm your appetite, making calorie restriction a tad more comfortable.

Most specifically though, we looked at how caffeine causes the release of adrenaline. This was the hormone that not only increased energy use, but also benefits fat burning.

The great thing about the EGCG inside green tea is that is slows down the breakdown of adrenaline (6). Consequently, the effects of the hormone are exaggerated.

According to meta-analysis, supplementing with caffeinated green tea can boost calorie burning by 4% for 24-hours after taking it. Fat burning can also see increases of 16% over the same space of time (7).


This ingredient is a chemical found within African yohimbe tree bark. It’s also quite a popular part of thermogenic supplements.

Yohimbe should, in theory, increase fat metabolism by boosting hormones such as; adrenaline, noradrenaline, and dopamine (8) (9).

There isn’t much evidence supporting it’s supposed fat loss benefits however, what’s out there does look good. One study showed yohimbe to help professional soccer players lose weight (10), while another suggested that it can be even more effective when combined with exercise (11).

Yohimbe risks & side effects

As with all supplements, there is some risk of side effects. Taking too much yohimbe or having a reaction could cause; stomach upset, jitters, anxiety, and/or headaches. The safest way to supplement with yohimbe is to always follow manufacturer guidelines. However, because of the risks involved, it isn’t one of the better thermogenic ingredients. Many companies won’t use it for this reason.


Also known as Paullinia cupana, Guarana is a climbing plant native to Brazil. Within it are a spectrum of stimulants, including the likes of theobromine, theophylline, and caffeine (12).

As you have already guessed, guarana can aid thermogenesis due to its potent caffeine content. Not only that, but the stimulant also helps to banish hunger, giving it another fat burning edge.

There are even test tube studies out there saying that guarana might suppress the genes that help fat cell production. According to these pieces of research, guarana might also benefit the genes that slow down fat cell production too (13)(14).

Guarana risks & side effects

Again, because of the stimulant content, users might experience jitters if taken in high amounts. The safest was to use guarana is to follow manufacturer guidelines and if you’re sensitive with stimulants, start with a small dose


We understand that the supplement marketplace is massive and you’re sure to have questions to ask. So, we’ve pulled together some of the most frequently asked questions about thermogenic ingredients and answered them in the section below.

Do Thermogenics really work?

To answer this question, we’ve got to be clear about the ones we’re talking about. In terms of individual ingredients, many have been proven under lab conditions to work. This can be said for the six we looked at earlier, for example.

Yet, when talking about combination products, not all are proven to work. While each of their ingredients might have evidence backing them up, a stacked product may not have been tested.

Therefore, it’s impossible to say all thermogenic supplements will work. To get a good measure of effectiveness you need to inspect its own, unique formula. One thing is for certain, however, and that’s the fact that fat loss can only happen when you’re in a calorie deficit. You must follow a wholesome diet when you eat less calories than you burn.

Are fat burners dangerous?

Fat burners are unregulated supplements therefore, they do carry a degree of risk. That’s why it’s always advised to choose an all-natural product from a reputable brand. Try to steer clear of supplements containing hidden proprietary blends and/or synthetic chemicals.

Another thing to always consider with fat burners is the level of stimulants. Taking too much caffeine, for example, can make users feel anxious, jittery, and cause problems with sleep. To stay safe when using fat burners, you should never exceed manufacturer guidelines.

What is the best fat burner supplement?

The best fat burner supplement is the one that fits your goals. While there are many products and ingredients out there, it’s always a smart move to check who they’re made for.

Hourglass Fit, for example, is a women’s only fat burner, designed to meet the demands of the female physiology. Others, such as a bodybuilding fat burner, might not be, and could focus more on muscle mass or more aggressive stimulant amounts.

To make sure you’re getting the best fat burning supplement for you, check out the product audience. Next, take a look at the reputation of the brand who makes it, followed by the ingredients. You should be able to find research behind each ingredient and see exactly why it’s included in the formula.

How can I reduce my stomach fat?

Stomach fat is one of the most common areas women want to change about themselves. Yet, anybody who has tried to lose it knows how hard it can be. There isn’t a secret, it’s all about being smart in the gym and even smarter in the kitchen. Firstly, make sure you’re eating less calories than you’re burning in a day. Keep your protein intake high, while dropping your carbs and fats a little. A 10-20% reduction of your usual calories should be both comfortable and effective. A high-quality fat burning supplement could help you here.

Secondly, don’t go crazy on the cardio and ab exercises. Instead, try to lift weights using compound movements like squats, presses and lunges, as these burn a lot of calories while building the most amount of muscle.

You won’t get bulky from lifting weights because you don’t have enough testosterone. Instead, you should become more toned with accentuated curves. Aim to hit the gym three to five times a week, performing full body workouts every time. By being consistent with both these things you should start to see results. Belly fat loss doesn’t happen overnight, it takes weeks to months to achieve.

Should I take thermogenic supplements?

Whether or not you take thermogenic supplements could be down to your goal. If you’re looking for something to amplify the effects of your fat loss diet, then the answer could be yes. Do you want to use them as a replacement for good nutrition or exercise? Then you probably shouldn’t take them. You’ll be disappointed with the results.

Also, you shouldn’t risk taking thermogenic supplements with stimulants in if you’re pregnant. Always check with your doctor before taking any supplement while pregnant or breast feeding.

How can I boost up my metabolism?

Boosting your metabolism can be done by eating the right thermogenic foods. This could be one of the options we listed earlier, a more convenient metabolism boosting supplement, or a high-thermogenic food such as protein.

Another way to boost your metabolism is to get physical. Lifting heavy objects like weight in the gym or sprinting can seriously fire up your calorie burn. While long jogs were once the way to go for fat loss, modern science says that’s no longer the case.

Instead, you should stick to lifting weights (which helps create and keep your feminine shape) and builds muscle (15). What’s interesting for many people to learn is that muscle is more metabolically demanding than fat, so, the more you have the more calories you naturally burn (16).

HIIT style workouts and sprinting has also shown some sought after benefits for boosting your metabolism (17). What’s more is that it also seems to increase calorie burning even after the workout has ended (18)(19).


So what are thermogenic supplements? Well, they’re dietary aids, designed to boost your metabolism, as well as your fat loss results. They’re widely used by everyone from stay at home moms to fitness fanatics as a way of accelerating weight loss.

Some thermogenic supplements are just a single ingredient, like; caffeine, capsaicin, green tea, and guarana, which are all proven by science to work. You can grab these all easily inside any health or supplement store.

However, many modern supplement companies create combinations of these ingredients to group their effects and make rather unique formulas. You might have seen these thermogenic supplements labeled as Fat Burners or similarly Metabolism Boosters. Note that these are rarely tested under lab conditions, yet, you can get a measure for how effective they’ll be by looking at their ingredient makeup.

Before we round up this article, let’s talk safety. Stimulant heavy thermogenic supplements might work great for some people, but they’re not always the best for women. Make sure you check out stimulant levels in a thermogenic supplement before you try it, and also consider how sensitive you are. Don’t use stimulants if you’re pregnant or think you might be.

Enjoy the fat loss effects of thermogenic supplements the best way. Use them to support a healthy diet, the exercise you do, and all your hard work.


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12. Bittencourt, L., Machado, D., Machado, M., Dos Santos, G., Algarve, T., & Marinowic, D. et al. (2013). The protective effects of guaraná extract (Paullinia cupana) on fibroblast NIH-3T3 cells exposed to sodium nitroprusside. Food And Chemical Toxicology, 53, 119-125. doi: 10.1016/j.fct.2012.11.041

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18. Hazell, T., Olver, T., Hamilton, C., & Lemon, P. (2012). Two Minutes of Sprint-Interval Exercise Elicits 24-hr Oxygen Consumption Similar to That of 30 min of Continuous Endurance Exercise. International Journal Of Sport Nutrition And Exercise Metabolism, 22(4), 276-283. doi: 10.1123/ijsnem.22.4.276.

19. Burns, S., Oo, H., & Tran, A. (2012). Effect of Sprint Interval Exercise on Postexercise Metabolism and Blood Pressure in Adolescents. International Journal Of Sport Nutrition And Exercise Metabolism, 22(1), 47-54. doi: 10.1123/ijsnem.22.1.47

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