Best Fat Burner Supplements for fast weight loss [Updated]

Author: Greatest Physiques

March 9th 2021

Welcome to the Greatest Physiques’ guide to the very finest 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 to burn off body fat quicker. 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).

These ingredients target fat cells and generate thermogenic reactions in your body which could have the effect of less fat. 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 amounts, which means you need to keep on 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.

The best fat burner supplements today.

So, now you know exactly what to look for, let’s get started. Here are the five pack leaders.


1. Instant Knockout CUT


  • Shred fat quickly, retain muscle and strength
  • Used by Pro MMA fighters to cut 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 has been a market leader for years. Originally created for pro MMA fighters, its unique formula is now a favorite for helping to burn body fat, without damaging muscle.

Despite its origins, Instant Knockout CUT isn’t just for athletes. Men and women of all kinds use it as their go-to-supplement for getting leaner while staying strong. It’s well-researched ingredient choices still stand out from the crowd and they’re generously dosed too.

One thing that keeps Instant Knockout CUT in the top spot is its customer reception. There are endless reviews for this product online and their website has great testimonials. For us, this is just as important as its impressive formula.

Instant Knockout CUT ingredients

  • Vitamin B6 – 5 mg
  • Vitamin B12 – 10 mcg
  • Vitamin D3 – 45mcg
  • L-Theanine – 100mg
  • Green Tea Extract (Leaf) – 500 mg
  • Green Coffee Extract (Bean) – 100 mg
  • Cayenne Pepper (Fruit) – 100 mg
  • Glucomannan (Konjac Root) – 1800 mg
  • Caffeine (Caffeine Anhydrous) – 300 mg
  • Black Pepper Extract (standardized to 95% PE) – 10 mg


Our team believe that Instant Knockout CUT stands above the competition for a reason. It delivers on all fronts and has solid, substantial evidence behind its ingredients.

Like we mentioned, lots of people have written testimonials talking about their results and it’s always well reviewed.

A standout feature for most users is the way Instant Knockout CUT helps energize their workouts – even when dieting. The smart caffeine combination will give you a clean lift without being intense or overbearing. It should also mean less risk of side effects from the stimulant.

Instant Knockout CUT is also free from proprietary blends, which is a big plus for us. Anybody who takes it knows exactly what is going into their body – there are no hidden chemicals or fillers. Deciding to be this transparent shows a company who is confident in their product.

We’d recommend Instant Knockout CUT to any man or woman looking to burn fat without losing muscle. Athlete or not, this fat burner could give your results an edge. It’s the best product on the market for us.


2. Hunter Burn

Hunter Burn - Best Fat Burner Supplements


  • Higher doses – 180 capsules per bottle
  • Thermogenic, appetite suppressant & carb blocker
  • Burns fat and retains muscle and strength
  • Cutting-edge formula
  • Contains only known carb blocker
  • L-theanine for improved focus


  • Only available direct from manufacturer
  • Higher price tag

In close second is the highly touted newcomer Hunter Burn. Released in late 2018, Hunter Burn is aimed toward the more affluent customer, namely aspiring businessmen and entrepreneurs.

This fat burner isn’t just another fitness focused product – it’s lifestyle specific. Hunter Burn was designed to keep men sharp and focused in the workplace, not just the gym. It also features a potent dose of glucomannan and the industry’s only known carb blocker[13].

Hunter’s goal was to deliver a fat burner that suited the fast-paced schedules of their customer. As such, burn is streamlined, high-grade, and premium. It has some of the most generous serving sizes we’ve seen among its cutting-edge formula.

Hunter Burn ingredients

  • Vitamin D3 (as Cholecalciferol) – 3000 IU
  • Konjac Root Extract (Amorphophallus konjac) – 3000 mg
    (Standardized to 90% Glucomannan)
  • White Kidney Bean Extract – 500 mg
  • L-Theanine – 200 mg
  • Matcha Green Tea – 200 mg
  • Cayenne Pepper – 125 mg


Hunter Burn has impressed customers and critics alike. Its creators have found a way to update the standard fat burner formula into something that suits busy, ambitious men.

Inside its streamlined formula are six potent ingredients, including the only known carb blocker. So, not only could Hunter Burn help you burn fat; it could buffer the backlash from overeating.

Another ingredient that stands out to us is L-theanine. This is a great addition for businessmen, as studies have shown it to improve focus and mental clarity[14]. Cognitive fatigue caused by controlling calories should be reduced after taking this amino acid.

Our only possible criticism of Hunter Burn is the cost. We understand that it’s made to provide maximum quality, but some people might prefer a cheaper option. That being said, Hunter Burn is definitely worth the price if you’re willing to pay.

Is bigger better when it comes to fat burners? If you are looking for a triple-action, top of the market product then yes. Hunter Burn has it all.



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 manufacturer

Taking third place is Hourglass Fit, a well-balanced fat burner with an impressive ingredient profile. Don’t let the marketing fool you, though. Although it’s mainly aimed at women, this product works well for men too.

After all, there is no such thing as a sex-specific fat burner. There are ingredients that work, and those that don’t. You’ll find a lot of the same ones in all kinds of fat burners. Most of the nuances are tailored for lifestyle or goals – not gender.

However, Hourglass Fit still takes a different approach from other fat-loss supplements. It contains no stimulants, which suits people who are sensitive to them. If you don’t enjoy the effects of caffeine, Hourglass Fit could be for you. What’s more, it features potent appetite suppressants to really make a difference against those calorie-restricted hunger cravings.

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


Hourglass Fit is one of the best female fat burners available today. Once you get past the marketing, it’s clear to see it has some great ingredients inside. All the key players like cayenne pepper, 5-HTP, and glucomannan are there – in decent amounts too.

We are impressed by the ingredient profile and the amounts, you get a full clinically proven 3g of glucomannan, which is the only proven appetite suppressant ingredient available. You get a thermogenic burn from the cayenne pepper and an energy boost from the vitamins.

If you are looking for a dedicated female fat burner, this is the one that we recommend.




4. Leanbean

Leanbean Official


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


  • Not very potent
  • Only available direct from manufacturer

Just like Hourglass Fit, our fourth pick Leanbean says it’s exclusively for women. But as we all know, that’s not necessarily true. Even though it’s ingredients apparently harness the power of nature, it doesn’t matter who’s taking them. Men respond in exactly the same way.

Inside Leanbean are 12 ingredients, including some of the key players you’d expect so see. Glucomannan is undoubtedly it’s main component – making Leanbean’s formula focused on controlling appetite.

However, there’s a lot more to this fat burner than managing hunger. It contains powerful antioxidant and anti-inflammatory ingredients too, for all-round health benefits.

Lean Bean ingredients

  • Vitamin B6 (as Pyridoxine HCI) – 1.7 mg
  • Vitamin B12 (as Methylocobalamin) – 2.4 mcg
  • Chromium (as Nicotinate Glycinate Chelate) – 35 mcg
  • Zinc (as Zinc Oxide) – 11 mg
  • Potassium (as Potassium Chloride) – 10 mg
  • Glucomannan – 3000 mg
  • Choline (as Choline Bitartrate) – 82.5 mg
  • Garcinia Cambogia (fruit) Extract – 100 mg
    (50% Hydroxy Citric Acid)
  • Green Coffee Bean Ext. – 50 mg
    (50% Chlorogenic Acids)
  • Turmeric (Curcuma longa) Root – 50 mg
  • Acai Berry Extract 10:1 – 20 mg
  • BioPerine®– 5 mg


Leanbean offers a unique formula that’s based around appetite control. We feel this makes it a superb option for anyone who has issues controlling cravings.

There’s also a lot of other health-promoting ingredients in there too. So, while it might not be the most effective fat burner, it’s well-suited to health-conscious men. There are powerful anti-inflammatory and antioxidants inside each capsule – making it a more holistic supplement than standalone fat burner.

We’re not sure if leaving out some of the more proven fat burner ingredients is the most ideal trade-off. It all depends on your goals and how aggressively you want to attack those fat stores.

While this is a good product, we think that Hourglass Fit is better.



5. Burn Lab Pro® Fat Burner


Burn Lab Pro


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


  • No extra appetite suppressants
  • Only available direct from manufacturer


Burn Lab Pro Ingredients

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

Burn Lab Pro Fat Burner is all about fat burning without compromising athleticism. Burn Lab Pro says its ingredients are chosen to optimize much growth and preserve lean mass, even during intense training.

Although its formula is super streamlined at only six ingredients strong, Burn Lab Pro still stands out. It’s routinely well-reviewed online and there’s obviously plenty of research behind it. Every ingredient has been proven to benefit fat loss or lean mass in some way.

Using such a small formula is a bold move – but it works. This is a supplement designed to provide stimulant-free fat burning that’s well-suited toward athletes. It isn’t an all-rounder and doesn’t pretend to be either. Burn Lab Pro keeps things simple, and we like it.


Why take fat burners?

There are many reasons why you might want to consider fat burner supplements, the most obvious being that you want to lose a few pounds. Ingredients like cayenne pepper, glucomannan and caffeine are common in most fat burners and can help you burn fat faster when taken with a healthy diet and exercise regime.

Common benefits of taking fat burners could include increasing your metabolic rate, turning your body fat into fuel and preventing you from feeling hungry so you eat less calories. Let’s take a look at common fat-burning ingredients and how they could help reduce your waist size.

Best fat burner ingredients

best fat burner ingredients

1. Cayenne Pepper Extract

If you’re a fan of spicy food, you’ll be familiar with cayenne peppers. A member of the chili pepper family, they have been grown and used for food and medicinal purposes for hundreds of years. They boast antioxidant properties, add a bit of fire to any dish but crucially, have been linked to increased metabolism and calorie loss [1].

There’s also some evidence to suggest that it could help you beat hunger by lowering the creation of the hormone ghrelin, meaning you could eat less food further reducing your calorie intake[2].

2. Glucomannan

Glucomannan is a familiar sight on the ingredients label of many fat burners and that’s because this dietary fiber is thought to have many fat burning benefits. It has been observed that glucomannan could absorb water from your intestines, making you feel full and preventing overeating[3].

Obviously, one of the biggest contributors to weight gain is excessive snacking or large portions, so feeling full for longer can help to eliminate the desire to consume too many calories. Glucomannan itself is also low in calories, making it a great all-round choice for any fat burners.

3. Green Tea Extract

Green tea is a fantastic, tasty drink and is becoming a key ingredient in many supplements thanks to its antioxidant ability. It is a popular additive in many fat-burning supplements as it is thought to have several benefits for trimming the fat.

Green tea is filled with catechins and caffeine, substances which have been linked to fat burning[4]. Catechins are antioxidants which have been shown in some studies to decrease body fat levels – and as a result, they’ll hopefully give you a slimmer waist.[5]

4. Caffeine

Wonderful coffee, where would we be without it? The world’s favourite hot drink is well known for its ability to wake you up and get you through a busy day, but it also has the potential to help you burn fat.

Coffee does this thanks to caffeine. Each coffee bean has a high concentration of the drug, and it has been shown in many studies to help burn fat by increasing your metabolic rate[6] and by sending signals to your fat cells to instruct them to break down[7].

You’ll generally see caffeine in the ingredients list on many fat burners and these are the reasons why.

5. 5-HTP

5-HTP is commonly used to boost levels of the brain chemical serotonin. But what does serotonin have to do with losing weight? A lot – according to science. Serotonin is known for its ability to boost mood, reduce anxiety and regulate the appetite[8]. All of these factors are crucial for successful fat loss – so having higher serotonin levels provides various benefits. 5-HTP has also been shown to reduce body mass index in women who took the supplement for 4 weeks [15].

How to use fat burner supplements

As we’ve mentioned, fat-burning supplements tend to come in capsule (or pill) form, and less frequently as a powder.

Advice on how to take fat burners will vary per product, but you will generally be instructed to take a certain number of capsules per day, usually before meals and with water.

We tend to prefer supplements that spread the servings right through the day, keeping the ingredients in your system consistently and evenly.

Many manufacturers advise taking their fat burner around 30 minutes before you eat. Doing this creates a chance for any appetite-suppressing ingredients to take full effect and stop you overeating.

That being said, it’s important to read the instructions for each product carefully. Follow their guidance should ensure you get the maximum benefit.

Fat burner benefits

The overarching benefit of fat burners is exactly as their name suggests – faster fat loss. However, there’s a lot of other nuances at play to get you to that end goal.

  • Increased fat mobilization

Certain ingredients inside fat burners are shown to increase fat cell mobilization. This is the process of breaking down fat cells into fuel, ready to be burned for human energy.

One way they can do this by triggering the release of hormones that instruct fat cells to break down their contents. Caffeine, for example, stimulates the nervous system and increases blood levels of adrenaline – a fat-breakdown-promoting neurotransmitter[9].

The other is by inhibiting enzymes that hold fat-breakdown-promoting hormones like adrenaline back. Green tea’s main catechin EGCG, for example, restricts enzymes that break down norepinephrine[10].

When your levels of hormones like adrenaline increase, fat mobilization does too. Fat cells are turned into useable fuel much quicker.

  • Boosted metabolism

Even while you’re resting, your body is still performing millions of functions. Each one requires a certain amount of energy too which comes from calories. How fast you burn through these calories is your metabolic rate.

A high-quality fat burner usually contains compounds that speed up your metabolism. As a result, you’ll naturally use up more calories per day – even when resting.

Most of these compounds are known as thermogenics because they raise your body temperature. You’ve probably already felt this phenomenon if you’ve ever tucked into a red-hot cayenne pepper.

The active compounds inside quickly stimulate your central nervous system and you start to heat up. It might not be by much, but a few degrees still make a difference.

You shouldn’t be able to tell this is happening after taking a fat burner. However, your body craves balance and will do everything it can to return to normal.

To get you back to baseline, your body will need extra energy. So, your metabolism gets a boost to help unlock this fuel from calories.

  • Appetite control

Keeping control of your appetite is one of the hardest parts of fat loss. Even if your exercise routine is the best is can be, it’s pretty much impossible to outwork a bad diet.

The problem is that cravings can strike at any moment. Restricting your calories makes hunger more likely to rear its head as well. Anybody who has tried to diet knows this feeling all too well.

Fat burner manufacturers pre-empt this and add appetite suppressors to their formulas. After all, their products can only work to their maximum effectiveness if their users don’t overeat. Supplements can’t override a calorie surplus – that’s just science.

Glucomannan is the most common appetite suppressant inside fat burner.  Yet, other ingredients like cayenne also have a track record of curbing cravings[11].

  • Energy

Energy can also be hard to maintain when dieting. Whenever you start to restrict calories, your body can switch into conservation mode and slow things down. You might start feeling lethargic and less motivated to hit that workout you promised you would.

Naturally, feeling flat isn’t helpful for fat loss. It’s all your fidgeting and exercising that burns the most calories – not sitting around.

Many fat burners contain sensible amounts of stimulants to support energy levels. Although they’re not actual food calories, they can help your body feel awake and your mind alert. Dieters might find that stimulants help them maintain their usual activity levels.

dumbbell curls

How to get the best out of your fat burner

If you’re looking to cut stubborn fat, your fat burner supplement will give you that kickstart on the right track. But to make those changes for good, there are a few really effective ways to help that fat loss along. We compiled our top 3 tips for healthy and sustainable weight loss that you can get started with right now.

  1. Clean up your diet

The first place to start when embarking on a healthier lifestyle is your diet. Eating ‘clean’ means turning your back on saturated fat, sugary and processed food and drinks. Try swapping in whole foods like leafy veg, lean proteins, fruit and healthy fats instead to cut that fat quicker. The good news is, premium fat burners contain appetite-suppressing nutrients like glucomannan to make that change to a healthier diet that much easier.

  1. Make an exercise plan

Whether you’re a keen strength trainer or just starting out, exercise really is the key to cutting excess fat. Experts say getting active at least 3-4 times a week will help accelerate weight loss. But busy lifestyles can often get in the way of keeping to that workout agenda so it’s time to make a plan. Devising a workout plan week by week will help you set aside time to fit in your exercise and ensure you stick to it too. So, whether you’re keen to lift more, get together with friends for a game of basketball, or want to start upping your cardio – schedule the time in and get active!

  1. Be consistent

One of the most fundamental parts of ensuring a supplement works to its full capacity is, of course, consistency. As with anything – like regular exercise and eating clean – consistency means your body has time to react and adjust to the changes. It’s the same with supplements. You need to give the supplement’s nutrients time to be fully absorbed into your body to maximize the benefits. So, make sure you take your fat burner supplements every day as per the specific label instructions to give it the best chance of working.

Fat burner side effects

Most people can use a high-quality fat burner without side effects. If they’re made by a reputable brand and use well-researched doses, the chances of adverse effects are minuscule.

But, it’s always important to check the ingredient label. If you’re allergic to anything on there, don’t take the product.

Caffeine sensitive people should also look for a stimulant-free fat burner. Although most brands use an amount that’s considered safe, you might want to test a smaller serving first.

Taking too much caffeine always runs the risk of making you feel jittery and unable to sleep. You might also experience stomach upsets, headaches, and nausea.

Best fat burner FAQs

Do fat burners work?

Because there are so many products, it’s impossible to say fat burners work across the board. What we can confirm though is that many of their ingredients are proven to work. So, if a fat burner has the right supporting science, it’s more likely to be effective.

For a fat burner to work, one thing has to always be in place – a calorie deficit. If you’re not eating fewer calories than your body needs, it won’t turn to your fat stores for fuel. It’ll use the calories you’ve eaten instead.

When should I take a fat burner?

You’ll ideally take a fat burner before your main meals through the day. This way the appetite supressing ingredients should be able to help stop you overeating.

Another reason to spread your fat burner capsules through the day is to avoid ingredient spikes. You won’t get a hit of stimulants in one go, and you’ll supply your body with a steady flow of nutrients.

 How can I lose my stomach fat?

Unsightly stomach fat is usually the kind we want to lose the most. Unfortunately, though, it can be one of the last to go.

To lose your stomach fat you need to be consistent with both your diet and workouts. Eat slightly fewer calories than your daily needs, lift weights, and be patient.

A fat burner could help by boosting your metabolism and unlocking fat cells. Some of their ingredients like green tea are proven to target unwanted belly fat too [12].

What are the best fat burners?

The best fat burners are the ones with proven ingredients inside. There are a lot of scientific studies looking at these, so the top-tier supplements always have evidence to back them up.

Do fat burners have side effects?

You shouldn’t experience side effects from taking a fat burner that’s high quality. Most dietary supplements are made by reputable companies who don’t overfill their capsules.

However, people have reported side effects from some ingredients. Excess stimulants could increase your heart rate, upset your stomach, cause headaches, and make you jittery. Try a smaller dose if you’re sensitive to them.

Our conclusion

Fat burners are a popular choice for people wanting to boost their fat loss. They can trigger thermogenic reactions inside your body, bolster energy levels, and even improve how well your body can unlock fat for fuel. Some can also help you control hunger, an essential part of fat loss success.

Adding a fat burner into your weight loss routine is simple too. Almost all of them are sold as capsules, so it only takes a second out of your day to swallow one. You don’t need to do anything else apart from let the ingredients get to work.

A high-quality fat burner could take you closer to your goals. But you need to set the right environment for it to work. So, you still need to put in the hard work and control your calories. Going to the gym and exercising is important too, if you’re able.


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