Instant Knockout Review – Does This Fat Burner Really Work?

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By Leslie Waterson

Reviewed by Juliana Tamayo, MS, RDN - Last Updated


The Instant Knockout fat burner supplement is designed to help you burn fat while building muscle.

Few supplements are as polarizing as fat burners, and people are either raving fans or passionate critics. With this Instant Knowout review, we are taking a look at this popular fat burner.

For those unsure about the topic, fat burners are a class of supplements that generally utilizes natural ingredients to help improve body composition through a reduction in body fat.

Instant Knockout Supplement

Often using proprietary formulations, these products typically work through one or more of three key mechanisms:

  • Adaptations in metabolism
  • Appetite suppression
  • Increased energy

Still, the biggest challenge with this class of supplements is that the rapid proliferation of products far exceeds the rate at which scientific studies can evaluate the claims.

So with that in mind, let us take a look at Instant Knockout. Our Instant Knockout review will provide an in-depth look at the supplement’s efficacy and safety. Feel free to jump around to the sections that interest you most.

Instant Knockout Review: Key Facts
Benefits Boosts Metabolism, Increases Energy, Promotes Fat Burning
Ingredients B-Vitamins, Green Tea Extract, Caffeine, and more
Pricing $59/bottle
Discounts Save Up to 33%
Company Roar Ambition LTD

Save Up To 33% Now

About Instant Knockout Fat Burner

Instant Knockout is a fat burner supplement by UK company Roar Ambition, and it first was on the market in September of 2014 (they have since produced a second version called Instant Knockout Cut).

With origins in helping MMA fighters and fight sports, the Instant Knockout brand is strong and exciting. The company immediately establishes credibility through association with successful fighters such as Diego Sanchez, John Dodson, and famous MMA coach, Greg Jackson.

This fat burner professes to be an ultra-powerful formula consisting of 10 fat-burning ingredients. Nonetheless, the formula undergoes exhaustive research to create a cutting-edge fat oxidation product.

Instant Knockout Ingredients

All in all, a supplement is only as good as the quality and quantity of the ingredients it contains. Instant Knockout claims to use the highest quality, natural variant of each of the ten core ingredients. We were happy to find that the company focuses on natural ingredients that constantly undergo research.

We also like the fact that Instant Knockout is not using any proprietary formulas in the manufacturing of its product. This means we not only have the exact ingredients but also the exact amount of each ingredient. This is crucial to our Instant Knockout review, as it allows us to analyze the true effectiveness of the supplement.

Unfortunately, they do exclude the entire vegetarian and vegan markets for their product by opting to use gelatin for their capsules.

Take a closer look at the Instant Knockout ingredients.

Ingredients List

Serving Size: 4 Capsules – Servings per Container: 30 Amount Per Serving % Daily Amount
Vitamin B6 (as pyridoxine HCI) 5mg 250
Vitamin B12 (as cyanocobalamin) 10mcg 166
Zinc (as zinc oxide) 10mg 150
GTF Chromium (as picolinate) 100mcg 82
Green Tea Extract (leaf) 500mg **
Green Coffee Extract (bean) 100mg **
Cayenne Powder (fruit) 100mg **
Glucomannan (konjac root) 1800mg **
Caffeine Anhydrous 300mg **
Black Pepper Extract (standardized to 95% PE) 10mg **

** Daily Value Not Established

Green Tea Extract


Instant Knockout, like other fat burners such as LeanBean, puts green tea extract as the powerhouse nutrient for fat loss in their formulation.

The company also references a couple of studies that do show a measurable effect in this regard.

For example, while one such reference cited shows that green tea extract helps with weight loss and weight management, the paper’s conclusion also makes clear that the positive results were not seen in those participants that already consumed 300mg of caffeine daily. This amount is about the same as a grande drip coffee from Starbucks.

Luckily, green tea has been extensively reviewed and there is a more recent meta-analysis from 2014 on the effects of green tea extract on body weight and body composition.

The conclusions were pretty clear:

CONCLUSION OF THE AUTHORS: Green tea or green tea extracts intake exerts no statistically significant effect on the weight of overweight or obese adults. There is a small effect on the decrease in the percentage of fat mass, but it is not clinically relevant.

Green tea will give you more energy, increase your metabolic rate, and promote better fat metabolism as well. In fact, we like that green tea does not just add caffeine content, but aids in burning fat.

Cayenne Pepper Powder (Cayenne Pepper Seeds)

The cayenne powder in this fat burner comes from cayenne pepper seeds. The magic ingredient in cayenne is a molecule called capsaicin known to have a whole host of medicinal properties.

In the context of Instant Knockout, capsaicin helps boost your metabolism, increases insulin sensitivity, and helps blunt the appetite. The cayenne might also help you in your weight loss journey and ultimately burn fat too.

One meta-analysis suggests that daily consumption of capsaicinoids may contribute to weight management through reductions in energy intake.—another highly respected resource that looks at ALL of the available scientific evidence—also suggests that capsaicin has modest benefits to boosting fat loss, stating:

The exact molecule found in hot peppers that burns your face off acts via adrenaline receptors and TRPV1 (like Evodia) to increase heat quickly. [capsaicin] Can burn body fat with minimal potency, fight inflammation with decent potency, and prevent cancer with indeterminate potency.


This next ingredient is a natural fiber product that comes from the root of the konjac plant.

In most cases, glucomannan is an appetite suppressant. While individual studies can be found that speak to the potential benefits of this compound to help with hunger management, this 2014 meta-analysis suggests otherwise:

CONCLUSION: The evidence from available RCTs does not show that glucomannan intake generates statistically significant weight loss. Future trials should be more rigorous and better reported.

Either way, adding fiber to your diet does promote weight loss by improving eating habits and keeping you full. It might also protect your GI system by helping good bacteria growth.

Caffeine Anhydrous

Before supplements as a class of products were even a thing, caffeine was being used to boost energy, reduce feelings of fatigue, and help improve mental focus. It is also a drug and class of stimulant that speeds up the signals between the brain and the body.

Furthermore, there is good evidence to support caffeine as an energy booster. A recent meta-analysis of 13 trials also found that caffeine use correlated with improvements in body composition.

Overall, the current meta-analysis demonstrated that caffeine intake might promote weight, BMI and body fat reduction.

The caffeine dose in Instant Knockout is a minimum of 300mg. In addition, here the caffeine comes in the form of caffeine anhydrous as well as the green tea in the formulation. This dose is split across four doses, meaning that every single dose is around 75mg or the equivalent of one small cup of regular coffee.

In terms of efficacy, 300mg is in line with the literature and resources, like Most studies use 4-6mg caffeine per KG of body weight (300-450mg for a 75KG/165lb individual).

A fat burner that includes caffeine often helps you lose weight by maintaining energy levels. Caffeine anhydrous, along with other ingredients in Instant Knockout, will lead to fat oxidation when paired with better eating habits and more energy.

Vitamin B6 and Vitamin B12

B vitamins are essential to energy production in the body. However, unless you are clinically deficient in these vitamins, the addition of B6 and B12 to a supplement is not going to help with fat loss or energy production.

Adding these vitamins to a fat burner will likely only help prevent deficiencies. Still, there is some evidence that vitamin B6 and B12 help focus and cognition.

Vitamin D3

This essential vitamin is good for all things immunity and bone health. It is likely in other supplements you have seen, and Instant Knockout is not different.

Taking vitamin D3 along with all the other ingredients in this supplement will lead to more satiety and even weight maintenance. Both of these combined can lead to fat oxidation with a good diet.


You might have heard that amino acids can help build muscle and even help with weight loss. in this case, L-theanine is effective in the general population because it can help maintain energy levels while promoting muscle growth.

Furthermore, if you are still on the fence, L-theanine can also promote immunity, increase focus, and might even act as an appetite suppressant.

Black Pepper Extract

There is very little evidence out there to support Piperine as an effective supplement in the context of fat loss.

The claims around thermogenesis are not wrong but they might not be too relevant. While there will likely be no negative effects of including piperine in the formulation, there just is not enough scientific data or human studies to support it.

That said, there are no common side effects, and it is common to find this ingredient in a weight loss supplement.

Green Coffee Bean

If you are wondering what these are, green coffee beans are simply unroasted coffee beans.

Most of the benefits of green coffee bean extract come from the antioxidant chlorogenic acid. Some studies in mice have shown it effective in helping the body to burn glucose and reduce body fat percentage in just a few weeks.

It is very common to find this ingredient in a weight loss supplement and it can often act as an appetite suppressant too.

Ingredient List

Instant Knockout Benefits

According to Instant Knockout, the primary benefit of this supplement is a boosted metabolism, with additional ingredients to reduce hunger cravings and increase energy levels.

If you are interested in losing weight and building muscle, this might be the right supplement for you. 


Here are some of the key benefits:

Boosts Metabolism

You can boost metabolism in different ways. Some of these include increasing the overall rate of calorie burn, improving insulin sensitivity, and opening specific chemical pathways that help break down stubborn fat deposits.

The Instant Knockout ingredients, such as cayenne pepper, chlorogenic acid, and coffee extract, all work to produce these changes in your body resulting in weight loss and reduced fat storage.

Although not 100% proven, these same ingredients will likely increase your metabolic rate when you follow a good diet and lifestyle.

Reduces Hunger Cravings

One of the biggest challenges with any form of calorie restriction is managing hunger, particularly if you are used to eating sweet stuff, and losing a few pounds seems impossible.

Like other fat burners such as PhenQ and Skald, Instant Knockout includes multiple ingredients to help suppress appetite and reduce hunger cravings. When combined all of these make Instant Knockout work better at managing your hunger levels.

Fuels Energy Levels

Whenever you restrict calories, we run the risk of having our energy levels decrease. Multiple ingredients in Instant Knockout are there to help drive up energy levels and thus support higher energy expenditure.

Helps You Lose Weight

Of course, the main benefit of Instant Knockout is helping you lose weight. The formula is designed to help your body with the fat-burning process.

However, even with initial weight loss, remember that if you take in more calories, you will likely not see much effect. Take Instant Knockout as directed and follow good lifestyle habits to get your body to lose weight. 

Dosage and How To Take Instant Knockout

Each bottle of Instant Knockout contains 120 capsules. Individuals should take one capsule, four times a day.

  • Take your first capsule, first thing in the morning
  • One before lunchtime
  • Take one more in the afternoon
  • And one final capsule before the evening meal

Claims vs. Reality

Whenever we review a health product, we like to compare the company’s claims to reality. 

As is the case with many fat loss products, Instant Knockout uses some emotive language throughout its website. They also try to position the product as the secret “cheat” that professionals have been using behind the scenes.

Of course, you only have to look at the training schedule of even a journeyman MMA fighter to know that the only “cheat” for them is hard work and a strict diet.

However, I will commend Instant Knockout in that they do not seem to make a lot of grandiose claims about their product. The company focuses on the ingredients and the research behind them, which you can find on the Instant Knockout website.

The company is transparent and mentions that Instant Knockout is intended for use in conjunction with a diet and exercise regime.

Lastly, you will find references to scientific journals and studies when there are any specific claims about the effectiveness of an ingredient. However, as is the case with all such efforts, the rest remains on the consumer to do their homework and actually look up the evidence.

As a result, you will frequently find the marketing narrative somewhat more optimistic than was generally inferred in the research.

Who Is Instant Knock Out For?

Despite a strong association with professional athletes and fight sports, Instant Knockout is for anyone looking for weight loss.

Even though the theme of the brand is overtly masculine, Instant Knockout goes out of its way to speak to the suitability of its product for women. You can find an entire section dedicated to them on the Instant Knockout website.

The best results will undoubtedly happen for those following a low-calorie or stricter diet and a regular training schedule.

Is Instant Knockout Safe?

The specific ingredients in Instant Knockout are all-natural and in quantities that appear to be safe and in the medical literature.

Most of these natural ingredients do not have side effects when you take them in the proper doses and have overall good health.

Of course, if you know you have a sensitivity to certain ingredients, you should read the ingredient list thoroughly to avoid any unwanted side effects.

If you are on medication, you should also check with your doctor before trying this fat-burning supplement. 

We think it is also worth mentioning that Instant Knockout is made in cGMP FDA-approved facilities in the USA and UK.

And if you are wondering, is Instant Knockout FDA approved? The answer is no. However, do not despair, because almost no supplement is.

Where to Buy Instant Knockout


Roar Ambition is trying to maintain tight control of the branding for Instant Knockout and clearly does not want it to be seen as a commodity product.

Consequently, you can only buy the product on the company’s official website here.

The official website lists pricing as follows:

Buying Instant Knockout is easy when you get the three-bottle stack nets you a fourth bottle for free, bringing the total monthly cost down to $46.25 — a saving of over $50 on the price of four individual bottles. 

You can also subscribe to save an extra 10% off, which you can skip and cancel at any time.

Although we do not see anything about a money-back guarantee, we do see that you can start the return process easily by contacting customer service. However, we are yet to see how good this service works.

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Value for Money

It is challenging to make a clear determination as to whether a product represents good value, largely because the value of a product comes down to its effectiveness and plenty of personal opinions.

One rudimentary way to evaluate value for money is to look at the top 50 best-selling fat burner products on Amazon.

At the time of writing, the average price of these products was $26.89, with only 6 of the 50 products going for more than $40.

From this perspective, it suggests that Instant Knockout is at best not cheap.

Instant Knockout Review: The Bottom Line

So here we are at the million-dollar $185 question—should you buy the Instant Knockout supplement? Hopefully, our review has shined some light on how the product works. Here are some common questions you may have.

Does Instant Knockout Really Work?

From the ingredients list, it is a solid maybe. Overall, we were happy with what we found in our Instant Knockout review.

There certainly is some evidence that each of the ingredients in it shows they can support one or more of the benefits of boosting metabolism, increasing energy, or reducing hunger cravings.

Overall, we will say that this makes Instant Knockout effective. No miracle supplement will magically melt fat, but Instant Knockout is a great supplement to combine with a healthy diet and exercise routine.

Instant Knockout Reviews

The Instant Knockout website presents a very convincing collection of user reviews and testimonials.

The product does also has some significant celebrity endorsements from respected fighters and coaches alike.

More so, we will say that this makes Instant Knockout effective. There is no miracle supplement that will magically melt fat, but Instant Knockout is a great supplement to combine with a healthy diet and exercise routine.

Should I Buy Instant Knockout?

It should be clear losing weight requires extreme discipline with both diet and exercise.

The Instant Knockout FAQ even positions its product as a bodybuilding supplement and makes it clear that you should be following a program of resistance training and a calorie-controlled diet to see results.

At the end of the day, fat loss comes with consistent hard training combined with a calorie deficit. Can Instant Knockout help you sustain achieve that through high energy levels and some improvements to satiety and hunger management? While the answer remains to be seen, if MMA fighters trust this product, so can you.

If you are going to try a fat-burning product, Instant Knockout is a great option. We have also reviewed dozens of similar weight loss supplements, and Instant Knockout is one of our highest-rated picks.

Even though we do not like that you have to stack Instant Knockout four times a day, you can start with a few a day, and see how you feel.

Overall Rating:
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Leslie Waterson

Leslie has been passionately involved in the health and fitness industries for over a decade. She is constantly reviewing the latest scientific research and studies in order to take a research-backed approach to lifestyle optimization. Her main areas of interest include nutrition and supplementation. Leslie shares her findings on Fitness Clone to help other health enthusiasts choose the products and routines that will help them achieve their goals.

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