5 Best Fat Burner Supplements for Weight Loss [Updated]

Author: Greatest Physiques

November 29th 2022

Welcome to the Greatest Physiques’ guide to the best fat burner supplements money can buy today! This guide is constantly updated to bring you the latest and greatest fat burner information brought to you from our team of health and fitness enthusiasts.

We scour the market and test a huge range of products, comparing them against each other to find the most effective fat burners for the best value. We don’t want you buying supplements which won’t have much effect or being ripped off on price, so check our best list for the best products!

What is a Fat Burner?

Fat burners are a popular type of supplement, often delivered in pill form (though sometimes powder), which contain ingredients that help you to burn fat at a faster rate than usual.

These ingredients, often derived from plants and foods, have various compounds which have been shown to increase the body’s fat-burning potential (detailed in the reviews below).

There are two ways in which most fat burners work:

  • Increase your metabolic rate to help your body burn more calories
  • Reduce your appetite, to help you consume fewer calories

It’s important to pick supplements with ingredients that have been supported by recent scientific research as many supplements can contain ingredients that have little or no effect.

Obviously, all products will include different ingredients, in different quantities, which means you need to keep an eye on what you’re taking and what you’re buying. We’ll handily list every main ingredient and show you the amounts, so you can make an informed choice before making any purchases.

Are Fat Burners Good for Weight Loss?

Fat burners work by either reducing the number of calories you consume by increasing satiety or by increasing the number of calories you burn by raising your metabolic rate.

Most offer both benefits. This can help you to improve your weight loss results, but it rarely works alone. You still need to exercise regularly, follow a calorie-deficit diet, sleep well, and manage your stress levels. Fat burners enhance your results and can make dieting feel slightly easier.

The Best Fat Burner Supplements Today.

So, now you know exactly what to look for, let’s get started. Here are the five best fat burners:

Best Fat Burner Supplements #1. Instant Knockout CUT


  • Shred fat quickly, retain muscle and strength
  • Used by Pro MMA fighters to cut body fat when it matters
  • Powerful natural formula
  • Works well for men and women
  • Thousands of positive customer reviews
  • No proprietary blends
  • Manufactured in cGMP- and FDA-approved facilities
  • Vegetarian and vegan friendly


  • Only available directly at the website’s maker
  • Premium-priced

Instant Knockout CUT Is our top-rated fat burner, and with good reason. It is packed full of top-quality ingredients that are well dosed and well-chosen for their tasks.

Instant Knockout Cut is designed to be taken alongside Instant Knockout’s other product, the meal replacement shake called Complete. But it works amazingly well whether taken alone or stacked with Complete.

The powerful natural formula has developed a cult following, and Instant Knockout Cut has thousands of positive customer reviews that describe how effective it is at both revving up their metabolisms and helping to reduce hunger cravings during diets.

Instant Knockout Cut has become very popular in the fighting community, with Pro MMA fighters, boxers, and wrestlers all using it to help them train hard while in a calorie deficit. This is alluded to in the name “instant knockout”. Check out our full review of Instant Knockout Cut for an even deeper dive into the pros, cons, and ingredients.

Instant Knockout CUT ingredients

  • Vitamin B6 – 5 mg
  • Vitamin B12 – 10 mcg
  • Vitamin D3 – 45 mcg
  • Glucomannan (Konjac Root) – 1800 mg
  • Green Tea Extract (Leaf) – 500 mg
  • Caffeine (Caffeine Anhydrous) – 300 mg
  • Cayenne Pepper (Fruit) – 100 mg
  • L-Theanine – 100 mg
  • Black Pepper Extract – 10 mg

As you can see, there are a number of well-dosed ingredients contained in Instant Knockout Cut. In this section, we will be taking a look at some of the most effective to give you a better idea of how they work.

Glucomannan (1800 mg)

Also known as konjac root, glucomannan is a form of dietary fibre that can help to suppress appetite and reduce hunger cravings [1]. As you can imagine, this can make a huge difference when trying to lose weight. Most people struggle between meals when dieting, which is why high-fibre foods are so effective during diets.

This is because fibre can help to slow stomach emptying after a meal, helping you to feel full for longer [2]. Glucomannan is incredibly effective at reducing snacking between meals and can make your diet a much more pleasant experience.

Green Tea Extract (500 mg)

There are many benefits to taking green tea extract. It can reduce LDL (bad) cholesterol [3], increase blood flow, lowers blood pressure, and can even increase your cognition [4]. But it is as a fat burner that Green Tea Extract is primarily known.

Studies have shown that green tea extract is particularly effective at fat oxidation [5], and the prioritisation of fat as a fuel during exercise is a major factor in green tea extract’s ability to lead to significant weight loss [6].

Caffeine (300 mg)

Unlike many fat burners on this list, Instant Knockout Complete is a stimulant-based fat burner, making it more effective overall. Caffeine is a natural stimulant found in tea, coffee, and some food products. It can increase fat burning in a number of ways. Caffeine can increase your metabolism, boost fat oxidation [7], and help you to train harder during workouts.

Studies have shown that combining a calorie deficit diet with the metabolic spike that caffeine creates can lead to significant weight loss over time [8]. Caffeine can also improve mood, boost your ability to focus, and increase motivation. It is best known for increasing wakefulness and banishing fatigue, very important when dieting.

L-Theanine (100 mg)

One of the things that people worry about with caffeine is the side effects. High-caffeine doses, while being highly effective for fat loss, have been associated with increased anxiety, jitteriness, and headaches. Luckily, l-theanine has been shown to reduce anxiety, prevent jitteriness, and help to elevate the cognitive benefits of caffeine. Studies have shown that adding theanine to caffeine can increase attention and boost mood more than caffeine alone [9].

Cayenne Pepper (100 mg)

One of the ingredients that all of the best fat burners seem to have is cayenne pepper. This is because it is non-stimulatory while also providing a spike in your metabolic rate that can lead to burning more calories and ultimately weight loss.


What makes Instant Knockout Cut stand out from the crowd is the effort it has put into covering all bases. Not only does it contain caffeine and green tea extract for central nervous stimulation, it also contains ingredients to boost your mood, suppress your appetite, and have you feeling happy and full of energy during your diet.

Combined with a calorie-deficit diet and frequent exercise, you can expect superb fat loss results with Instant Knockout Cut. All while feeling energetic, motivated, and relaxed. If you want to push your results even further, then why not consider combining Cut with Instant Knockout’s other product Complete? A meal replacement that is designed for weight loss.

Best Fat Burner Supplements #2. Hunter Burn

Hunter Burn - Best Fat Burner Supplements


  • High dosages of ingredients
  • Thermogenic, appetite suppressant & carb blocker
  • Burns fat and retains muscle and strength
  • Cutting-edge formula
  • Contains a highly effective carb blocker
  • L-theanine for improved focus


  • Only available direct from the manufacturer
  • Premium price tag

Geared towards businessmen and women on the go, Hunter Burn is a premium product with a price tag to match. But don’t let the high price fool you, this is one of the best fat burner supplements around. Hunter Burn more than justifies its price tag through its top-quality ingredients and generous dosages. When you look at the ingredients list you’ll note that there is often twice as much of each ingredient as competing brands.

But this isn’t just a question of throwing in ingredients for the sake of it, each ingredient has been intelligently chosen, and they are all designed to work together well. There is a lot of vitamin D as this is a common deficiency, particularly in winter. They have also added konjac root extract and white kidney bean extract to help with satiety and to lower carbohydrate absorption.

The combination of l-theanine and matcha green tea means that you can get increased fat oxidation, improved mood, and increased cognition. Finally, there is cayenne pepper which can help to boost your metabolic rate by increasing thermogenesis.

Hunter Burn Ingredients

  • Vitamin D3 (as Cholecalciferol) – 3000 IU
  • Konjac Root Extract (Amorphophallus konjac) – 3000 mg
  • White Kidney Bean Extract – 500 mg
  • L-Theanine – 200 mg
  • Matcha Green Tea – 200 mg
  • Cayenne Pepper – 125 mg

As you can see, Hunter Burn contains a number of similar ingredients to Instant Knockout Cut, we’ve highlighted a few differences and will go into more detail below:

Vitamin D3 (3000 IU)

Vitamin D is often looked at from a hormonal point of view, and there is certainly a lot of evidence that addressing a deficiency can lead to increased testosterone levels in men [10]. But vitamin D supplementation has also been shown to be surprisingly effective at reducing body fat in overweight men and women.

A 2012 study found that over a 12 week period, high doses of vitamin D were associated with a drop in fat mass in overweight women [11]. Correcting a vitamin D deficiency can also help to reduce the risk of cardiovascular disease, reduce the risk of colorectal cancer, and lower blood pressure. Hunter Burn contains 3,000 IU which is considered a very generous dosage.

Konjac Root Extract (3000 mg)

Konjac root is another name for glucomannan, so we have already covered this ingredient in the Instant Knockout Cut ingredients section. However, we thought we’d mention it again because of the very high dosage. 3000 mg is roughly double the amount used in most supplements and will give you an advantage when it comes to reducing hunger cravings.

White Kidney Bean Extract (500 mg)

White kidney bean extract is the only known carb-blocking ingredient that actually works. There is a lot of evidence that taking white kidney bean extract alongside a high-carb meal can reduce absorption and reduce blood glucose and triglyceride levels [12].


Hunter Burn is one of the best fat burner supplements around. It uses high dosages of effective ingredients, avoids any duds, and offers a low-stimulatory fat burning experience thanks to its preference for matcha green tea over regular caffeine. The use of l-theanine is a great shout as it can reduce anxiety and depression while boosting cognition and improving mood.

The ability to eat more carbohydrates than usual on a diet thanks to the white kidney bean extract should not be underestimated. Hunter Burn also helps to prevent hunger and cravings due to its very generous dose of glucomannan. This is a premium product, and well worth the price.

Best Fat Burner Supplements #3. Hourglass Fit

Hourglass Fit fat burner review


  • Works hard to shred belly fat
  • Helps to give you a sexy Hourglass Fit figure
  • Designed for women
  • Powerful high-quality ingredients
  • Effective caffeine-free formula
  • Free UK & USA delivery
  • Vegan friendly


  • Only available from the manufacturer

Taking third place is Hourglass Fit, a well-balanced fat burner with an impressive ingredient profile. Although Hourglass Fit is primarily aimed at women, this product works well for all genders.

Unlike Instant Knockout Cut and Hunter Burn, Hourglass Fit avoids the use of stimulants completely. Using ingredients that can suppress appetite or boost your metabolic rate without stimulating the central nervous system.

This can be used by people who want to avoid stimulants, or for people who already consume a lot of caffeine. Either socially, or as part of their pre-workout routine. Hourglass Fit uses glucomannan to increase satiety, cayenne pepper to increase thermogenesis, and 5-HTP to boost serotonin while reducing your appetite.

Hourglass Fit ingredients

  • Vitamin B6 – 1.7 mg
  • Vitamin B12 – 2.4 µg
  • Chromium (as Picolinate) – 125 µg
  • Zinc (as Citrate) 8 mg
  • Vitamin B2 (as Riboflavin) – 1.1 mg
  • Glucomannan – 3000 mg
  • Cayenne Pepper Extract – 100 mg
  • Black Pepper Extract – 5 mg
  • 5-HTP – 150 mg


While most fat burners contain at least a few vitamins, Hourglass Fit has added vitamins B2, B6, and B12 to their ingredients list, as these can help improve women’s health. While none of these vitamins is seen as a fat burner, they are all integral to the proper maintenance of your metabolism and are crucial for fat oxidation.

Vitamin B2 supplementation can help to restore healthy skin and hair [13] and protect your immune system. Vitamin B6 has many functions, but is also a crucial component of a healthy menstrual cycle, helping to reduce the effects of PMS [14]. Vitamin B12 is added to help reduce fatigue, improve mood, and combat depression.

Chromium Picolinate (125 µg)

Chromium picolinate is a really interesting ingredient, found in some of the best fat burner supplements. Several studies have shown that chromium picolinate can help to reduce appetite, helping overweight people to reduce their food intake easily [15], over time this can lead to significant weight loss.

Chromium can also improve blood glucose levels and is increasingly being looked at for its mood-enhancing abilities. Studies found it to be quite effective at treating some of the symptoms of depression [16].

5-HTP (150 mg)

Considering the number of benefits associated with 5-HTP supplementation, it is surprising that more of the best fat burner supplements don’t utilise it. A number of studies have found it to be highly effective at reducing appetite in both men and women [17]. This has inevitably led to statistically significant weight loss in studies on overweight people [18].

5-HTP may also help to improve sleep quality and improve mood. A 2010 study found that a non-depressed male who had recently terminated a relationship saw a significant drop in relationship-related stress after taking 5-HTP [19].


Hourglass Fit is one of the best female fat burners available today. It functions perfectly as a non-stimulatory fat burner, and this alone justifies its selection on our list of the best fat burner supplements. But what we really like is the ways in which they have added in ingredients such as vitamins B2 and B6 that have specific benefits to women.

There are a lot of really clever ingredients in Hourglass Fit. We particularly like the addition of 5-HTP, chromium picolinate, alongside the big hitters (glucomannan, cayenne pepper). If you are looking for a stim-free fat burner, then Hourglass Fit is a superb choice.

Best Fat Burner Supplements #4. Leanbean

Leanbean Official


  • Affordable
  • Contains antioxidants and anti-inflammatories
  • Lots of glucomannan
  • Suitable for men and women
  • Natural
  • No proprietary blends


  • Not very potent
  • Only available direct from the manufacturer
  • Several useless ingredients

Just like Hourglass Fit, our fourth pick Leanbean is exclusively aimed at women. They even have similar ingredient lists. However, there are a few notable differences between the two, where Leanbean has (frustratingly) used non-effective ingredients instead of effective ingredients such as 5-HTP or cayenne pepper extract.

Still, there is a lot of good, and Leanbean deservedly ranks quite highly on our list. Unlike Instant Knockout Cut, which has a powerful fat burning formula, Leanbean uses subtlety and strategy to maximum effect. They offer a fat burner that helps you feel better while dieting and see faster weight loss results.

Lean Bean Ingredients

  • Vitamin B6 – 5.6 mg
  • Vitamin B12 – 0.8 mcg
  • Chromium – 11.7 mcg
  • Zinc – 3.67 mg
  • Potassium – 3.33 mg
  • Glucomannan – 1000 mg
  • Choline (as Choline Bitartrate) – 27.5 mg
  • Garcinia Cambogia (fruit) Extract – 33.33 mg
  • Green Coffee Bean Ext. – 16.67 mg
  • Turmeric (Curcuma longa) Root – 16.67 mg
  • Acai Berry Extract 10:1 – 6.67 mg
  • BioPerine®– 1.67 mg

Potassium Chloride (3.33 mg)

Potassium chloride is an odd choice for a fat burning supplement. Leanbean justifies it by claiming that potassium chloride can aid normal digestive function.

They even link to a study which mentions this [20]. But as the study itself says, there is no evidence that a chloride deficiency leads to impaired digestion. So, what is the point of it in this fat burner?

Choline (27.5 mg)

Leanbean has added choline as it is known to be important for normal lipid metabolism, however, the standard dosage for choline is between 250 and 500 mg [21], whereas Leanbean contains just 27.5 mg.

Garcinia Cambogia Extract (33.33 mg)

This is another ingredient that is seriously underdosed (400 mg lower than the standard), but Garcinia Cambogia extract does at least work quite well as an appetite suppressant [22]. As Leanbean already has glucomannan, we’re not sure what the need for Garcinia Cambogia extract is. They have the same function.

Green Coffee Bean Extract (16.67 mg)

Again, underdosed and not particularly effective. A couple of studies have found that green coffee extract can lead to weight loss [23], but this was with doses of 120-300 mg rather than the 50 mg contained within Leanbean.

Turmeric (16.67 mg)

Turmeric (specifically the antioxidant curcumin that is found in turmeric) has many health benefits. It can lower triglyceride levels, reduce inflammation, reduce some of the symptoms of depression, and reduce pain. It also increases blood flow. However, again, the dosage of turmeric is too low to be effective.

This is a shame because turmeric would have been a game-changing addition to Leanbean if it had been properly dosed!

Acai Berry Extract (6.67 mg)

There are many supposed benefits to eating acai berries as part of a healthy diet, but acai berry extract does not have the same levels of research behind it. Acai berries appear to lower cholesterol, boost cognition, and may help to reduce the risk of certain cancers. The dosage of 6.67 mg is very low though.


Leanbean offers a unique formula that’s based on appetite control. There are a number of highly effective ingredients, and they do the vast majority of the work.

Sadly, the formula is bloated with a large number of underdosed or ineffective ingredients such as acai berry extract, green coffee bean extract, and severely underdosed turmeric.

It would have been better for everyone (including Leanbean) if they had cut out the underdosed ingredients and instead focused on fully dosing the ones that worked. Cut out acai berry, and fully dose turmeric (for example).

We would still class Leanbean as one of the best fat burner supplements thanks to its use of glucomannan, chromium, vitamins B2, B6, B12, and Bioperine. However, until they fully dose the other ingredients, Leanbean will always be a poor imitation of Hourglass Fit.

Best Fat Burner Supplements #5. Burn Lab Pro® Fat Burner

Burn Lab Pro


  • Muscle protecting
  • Stimulant free
  • Vegan friendly
  • Competitive price


  • No extra appetite suppressants
  • Only available direct from the manufacturer

Burn Lab Pro is an interesting fat burner supplement to finish our list with. Rather than trying to help you burn more fat, Burn Lab Pro is more focused on helping you to train hard and build muscle while dieting. That’s not to say that it doesn’t also help with fat burning, it does. But fat burning is a secondary concern.

Burn Lab Pro Ingredients

  • GTF Chromium (As NutriGenesis®) – 90 mcg
  • Calcium – 262.5 mg
  • HMB (ß-Hydroxy ß-Methylbutyrate) – 1500 mg
  • Coleus Forskohlii root (as Forslean®) – 375 mg
  • Cayenne Pepper Extract (as Capsimax®) – 75 mg
  • Black Pepper Extract (as BioPerine®) – 3.75 mg

HMB (1500 mg)

One of the downsides to staying on a diet for a prolonged period of time is that you can begin to lose muscle mass. That’s why a high-protein diet is so useful because protein can prevent muscle breakdown.

HMB is a metabolite of the amino acid leucine, and it is highly effective at preventing muscle breakdown [24]. This fits in nicely with the goals of Burn Lab Pro, which is to allow you to train, recover, and even build muscle while in a calorie deficit.

Coleus Forskohlii (375 mg)

This is a pretty cool ingredient that may well help with fat loss, particularly in overweight or obese people [25]. It also appears to restore testosterone levels in men (but not women) and could also help to increase muscle mass.


Burn Lab Pro Fat Burner is a great supplement to take while in a calorie deficit as it allows you to train, build muscle, and recover well while dieting. This should not be underestimated. However, as an out-and-out fat burner, Burn Lab Pro cannot compete with the best fat burner supplements.

This is a supplement that could really do with a stimulant such as caffeine added to it, as this would ramp up the calorie-burning and help with training hard during a workout. We’d also like to see an appetite suppressing ingredient such as glucomannan to help make it easier to avoid snacking or craving food.

Best Fat Burner Supplements for Weight Loss: Final Thoughts

When it comes to burning fat, you want a three-pronged approach: Diet, exercise, and supplementation. Finding the best fat burner supplements for weight loss can really help you in that regard. Instant Knockout Cut is by far our favourite, with its aggressive approach to ramping up your metabolism while reducing hunger.

Hunter Burn does a great job in second place, providing a lower-stim experience, but placing more emphasis on appetite suppression, mood, and cognition. In third place, we have an amazing fat burner aimed at women. Hourglass Fit has a clever, strategic ingredients list, and really delivers the best non-stim fat burning experience.

Leanbean is a good fat burner that could eventually be elevated to great if they would just stop messing around with the formula. Cut out the poor ingredients, properly dose the good ingredients, and suddenly you have a really decent product.

In fifth place, we have Burn Lab Pro, which is a great supplement to take while dieting, but can’t be considered a top tier fat burner when the majority of its ingredients don’t tend to burn much fat! Still, a great supplement in its own right, and something a bit different from the other fat burners on this list.

Best Fat Burner Supplements FAQs

Do fat burners work?

Yes, high-quality fat burners can work when used in conjunction with a calorie-deficit diet and regular exercise. The best fat burner supplements use ingredients that can enhance your diet and exercise program. Increasing fat oxidation, reducing appetite (particularly cravings), and helping to keep you calm, relaxed, and motivated throughout.

When should I take a fat burner?

Yes, if you are already dieting and/or exercising regularly then a good fat burner can help to improve your results. Stick to the best fat burner supplements and talk to your doctor first if you have any allergies or take medication.

 How can I lose my stomach fat?

While you cannot target belly fat, you can diet and exercise to lose overall body fat, and if you have excess fat around your stomach then this will eventually go. Creating a calorie deficit by moving more, consuming less, and raising your metabolic rate will speed up your results.

What are the best fat burner supplements?

Any of the five supplements on this list can be considered to be a good choice. In our opinion, the best fat burner is Instant Knockout Cut, with Hunter Burn a close second. While women can get amazing results from either, they may want to try Hourglass Fit, which has been specifically designed for women.

Do fat burners have side effects?

Some fat burners can do, particularly ones that contain caffeine. However, Instant Knockout Cut, which contains 300 mg of caffeine uses l-theanine to help prevent the side effects associated with caffeine use.

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