Instant Knockout Review – Effective Fat Burner or Nah?

Here's a full review on the ingredients in Instant Knockout and more.

We select products we think are useful for our readers. We may earn money when you click on links on this page. View our disclosure for more details.

Instant Knockout Fat Burner Review: The product is from the UK-based company Roar Ambition who offers a variety of performance products.

This product is marketed as a shredding formula and it’s a natural, multi-ingredient supplement that is used and trusted by professional combat sports athletes (hence the name). However, its use is not limited to this particular group of individuals, and therefore, it’s really an option that any healthy person can consider.

The super-cool bottle design (shaped like a fist) and interesting ingredient profile had me intrigued, so I had to look into Instant Knockout for myself. So, here’s my full review of Instant Knockout fat burner:

Best Price

4 Gauge Pre-Workout Review

Instant Knockout fat burner is a natural, multi-ingredient supplement that is used and trusted by professional combat sports athletes.

Also, check out our 4 Gauge pre-workout review

Key Features

  • B6 and B12 are important for converting food into energy, transporting oxygen to cells, creating red blood cells, and using folic acid.
  • Zinc is an essential mineral that is important for immune health, protein synthesis, DNA synthesis, growth, and development, and the catalytic activity of approximately 100 enzymes. 
  • Green tea extract has health-promoting compounds.
  • Cayenne has been shown to increase appetite suppression.
  • Caffeine provides an energy boost and a thermogenic effect.
  • Glucomannan is a potent fiber that has shown in studies to support weight loss.

Instant Knockout Ingredients/Potential Benefits

Instant Knockout contains some pretty interesting ingredients and we’ve provided some research-backed evidence to show the potential benefits of each one. 

Instant Knockout Ingredients
Instant Knockout Ingredients

GTF chromium picolinate

Chromium is a mineral that the human body only needs in very small amounts. Research shows that chromium is important for maintaining the function of insulin in the body; which is to effectively store and allow the body to metabolize carbs, fats, and proteins. 

Therefore, it’s believed that it may help to improve insulin sensitivity in those with Type 2 diabetes. While a few studies have shown a positive effect. The overall evidence isn’t sufficient to suggest that it’s effective for improving blood sugar health and it’s a subject of much controversy. (1, 2, 3)

Research is also inconclusive about the other potential health benefits of chromium. 

Dose per serving: 100mcg (82%)

Green tea extract

Green tea has been used in Asia for its potential medicinal purposes for many years and there are some notable health benefits. Green tea contains polyphenol antioxidants called catechins, of which the catechin epigallocatechin-3-gallate (EGCG) is known to possess the most health-promoting properties.

Antioxidants help stave off diseases due to dangerous free radicals that damage body cells. These catechins make up most of the antioxidant content found in green tea.

Instant Knockout contains an effective dose of green tea near the higher end of a recommended daily dosage

Green tea has several health-boosting benefits and a long history which makes it an great beverage of choice. Check our our review of 12 Best Green Tea Brands on the market.

Mental performance and energy

Now, because green tea extract does naturally contain caffeine, the effects on mental alertness are a no brainer. Not to mention, caffeine boosts energy levels as it’s a nervous system stimulant and to date, there’s really no ingredient better for this purpose. Green tea typically contains less caffeine than like a cup of coffee though but it still contains it in noticeable levels. 

Instant Knockout
Instant Knockout

Weight loss

According to research, the combination of caffeine and catechins in green tea has a notable effect on energy expenditure. Although, one study determined that the mechanism by which these compounds have this effect may be explained by thermogenesis, fat oxidation, or both. (4)

Other potential health benefits

The catechins in green tea may have positive effects on insulin sensitivity, heart health, brain health, exercise performance, recovery, and possibly even cancers. 

Dose per serving: 500mg

Green coffee extract

Green coffee contains chlorogenic acids that have antioxidant and anti-inflammatory effects which is good for overall health/disease prevention. (5, 6

In fact, one study of individuals with metabolic syndrome who took 800mg of green coffee extract over 8 weeks, saw significant improvements in fasting blood sugar, blood pressure, and waist circumference. (7)

But as far as the potential for promoting pure weight loss, most promising studies have shown notable improvements in mice. There need to be better quality studies in humans to suggest that it may be a viable option for supporting weight loss. (8

While there isn’t necessarily a recommended dose for green coffee extract, much higher doses than 100mg have been taken safely. This would imply that 100mg is rather low per serving however, with the caffeine and green tea, the caffeine content will already be high enough. 

Dose per serving: 100mg

Cayenne pepper

Cayenne pepper is a popular food used to spice up dishes but there are health benefits to be had with these chilis mainly due to the active ingredient, Capsaicin (gives the spiciness). 

Cayenne also contains a respectable amount of health-promoting antioxidants. One tablespoon of cayenne contains 44% vitamin A, 8% vitamin E 7% vitamin C. Plus, it provides a little vitamin B6, vitamin K, and a few other key nutrients in small amounts. 

Weight loss

Pepper has long been believed to contribute to weight loss because the spice can have metabolic-boosting effects. Cayenne induces a small thermogenic effect, therefore, leading to more calories burned. (9)

However, this effect is nothing to write home about as you’d be better off focusing on a good exercise and diet regime if you’re looking to improve body composition. 

But it’s also important to note that cayenne has been shown to reduce appetite which would have an even larger effect on weight loss and obesity management. (10, 11, 12)

Other potential health benefits

Cayenne may be a therapeutic ingredient for reducing cancer risk, improving digestive health, and possibly lowering blood pressure, although most studies have been done in mice for potential heart health benefits. (13, 14, 15)

There’s no recommended serving for cayenne pepper although 100mg is within a safe and effective range. 

Dose per serving: 100mg

Glucomannan (konjac root)

Glucomannan is a water-soluble fiber from the konjac root or elephant yam, which is added to many food products including as a food additive. 

Weight management

It soaks up a lot of water and because this takes up a lot of room in the stomach, it can increase the feeling of satiety. Not to mention, Glucomannan delays stomach emptying, further contributing to the feeling of fullness. (16)

Glucomannan also feeds gut bacteria and a healthy gut is associated with a healthier weight. (17, 18)

Several studies have found that taking Glucommanan in combination with a calorie-restricted diet promotes significantly more weight loss than a calorie-restricted diet alone. (19, 20)

In fact, this was the case in a large and prominent study of 176 overweight individuals who took Glucommanan with a 1200kcal diet for five weeks. The Glucomannan group experienced much more weight loss compared to a placebo group. (21)

This is promising evidence for using Glucommanan as a weight loss aid. However, a restricted-calorie diet is also always necessary. 

Other factors of health

Research shows that Glucomannan may also be beneficial for heart health by reducing cholesterol and triglycerides, while also lowering fasting blood sugar which means it can help to reduce the risk of developing Type 2 diabetes. (20)

Glucomannan is also a great option for helping to treat constipation. (21)

Overall, Glucommanan seems to be an effective option for supporting weight loss. 

Dose per serving: 1800mg

Caffeine anhydrous

Caffeine is a nervous system stimulant that has shown to increase calorie expenditure, therefore, It may also help with the weight loss process. It’s also the most effective ingredient in any product for providing unparalleled energy. 

Instant Knockout contains a powerful dose at 300mg per serving which is actually on par with many pre-workouts. If you can maximize that increase in energy, you can definitely burn more calories. 

Dose per serving: 300mg 

Black pepper extract (standardized to 95% PE)

Black pepper extract contains a compound called piperine which is commonly used in supplements to improve ingredient absorption such as the compounds in green tea, for example. 

But black pepper also contains antioxidants and has anti-inflammatory properties. (22)

There may be other potential benefits, although studies have been mostly in rats and via test tubes. 

Although one study in 86 overweight humans found the piperine in addition to epigallocatechin gallate and capsaicins significantly improved insulin sensitivity over 8 weeks. However, because there were multiple ingredients used, it wasn’t determined that black pepper can have this effect all on its own. (23)

But the good thing is that Instant Knockout contains the other ingredients in the study, therefore, we could say that this is an effective ingredient combination. 

Dose per serving: 10mg

Other Ingredients 

Other ingredients include gelatin (not vegan/vegetarian), silicon dioxide, titanium dioxide, magnesium stearate, FD&C Red 40. 

The ingredients consist of additives and fillers

Can Instant Knockout Cause Side Effects? 

There’s a decent amount of caffeine in Instant Knockout from the caffeine itself to the additional caffeine contained in some of the other ingredients. If you have not built up a solid tolerance to caffeine, it could cause some undesirable side effects such as nausea, dizziness, palpitations, anxiety, fatigue, etc. 

Yes, the doses are split up but for someone new to caffeine, there’s a good chance that it may potentially cause a few of these side effects. 

You also don’t want to pair Instant Knockout with other caffeine or stimulant-containing products.

Individuals with health issues or who are taking medications should consult with a doctor prior to use. 

Instant Knockout Bottle
Instant Knockout Bottle

How To Take It

Per the product instructions, you should take 1 capsule with a glass of water fur times per day. More specifically, they recommend you take one cap first thing upon waking and before breakfast, the second in between breakfast and lunch, the third an hour after lunch, and the last capsule an hour before dinner. 

They also suggest taking a serving no later than 5 hours before bedtime. 

Cost/Serving Size

Instant Knockout may cost a bit more than a lot of people would like to spend on a fat-burner. But it’s certainly not the most expensive product in its category. Here’s the pricing information. 

  • 1 bottle/1-month supply: $59 (you pay to ship)
  • 2 bottles/2-month supply: $118 (free delivery in the UK and US)
  • 3 bottles +1 free/$185 (free worldwide delivery) 

As you can see, the best option is the 3-month supply because you get a free bottle and free shipping anywhere. This brings the cost per bottle down significantly compared to the other two options. 

One bottle is $59 plus shipping and although not cheap, this is the best option if you want to test it out to see if you like it before committing to a 2 or 3+1 month supply. 

Best Price

4 Gauge Pre-Workout Review

Instant Knockout fat burner is a natural, multi-ingredient supplement that is used and trusted by professional combat sports athletes.

Instant Knockout Serving Size
Instant Knockout Serving Size

Is Instant Knockout Worth The Buy?

While there are a few effective ingredients for supporting weight loss and performance, Instant Knockout isn’t necessarily a groundbreaking formula. It’ll likely help to burn extra calories due to the combination of caffeine, green tea, cayenne, and Glucomannan which seems to be an effective bunch of ingredients. Not to mention, the other potential benefits of these ingredients.

But buying one bottle at a time isn’t necessarily realistic for everyone so the budget should definitely be taken into consideration. Overall though, I think its worth a shot!


Instant Knockout is a knockout fat burner and a weight loss product that could potentially help to improve body composition. However, it’s up to you to achieve your desired results which means you need a good exercise/training and diet regime. No supplements will do all of the work for you but they can give you that little edge you need and this may be a viable option. 

For the latest news and updates please follow us on Instagram, Facebook and Twitter.

The Review

Instant Knockout

8.7 Score

Instant Knockout is a great knockout weight loss product that could potentially help to improve body composition. However, it's up to you to achieve your desired results which means you need a good exercise/training and diet regime.


  • Natural ingredients
  • Several research-backed ingredients
  • No proprietary blends
  • Good for both men and women
  • Super-cool bottle design


  • A little pricey
  • High in caffeine
  • Contains synthetic red dye

Review Breakdown

  • Ingredients
  • Effectiveness
  • Price

Instant Knockout DEALS

We collect information from many stores for best price available

Per Serving

Matthew Magnante
Matthew Magnante
Matthew Magnante is the senior writer for Fitness Volt. He has had a passion for fitness since elementary school and continues to research and learn how to build muscle effectively through training and diet. He also loves to help others to achieve their fitness goals and spread the knowledge where needed. Matthew's other passions include learning about mindfulness, strolling through nature, and always working to improve overall.

Leave a Reply

Your email address will not be published. Required fields are marked *

Related Posts



This article was written by one of our qualified writers, and fact-checked by our experts. The numbers in parentheses (e.g. 1, 2, 3, etc.) throughout the article, are reference links to peer-reviewed studies.

Our team of experts include a board-certified physician, nutritionists, dietitians, certified personal trainers, strength training experts, and exercise specialists.