Few supplements are as polarizing as fat burners, and people are either raving fans or passionate critics. With this review, we’re taking a look at Instant Knockout—a popular fat burner that was originally developed to help professional boxers and MMA fighters burn fat in preparation for an upcoming fight.
For the uninitiated, fat burners are a class of supplements that generally utilizes natural ingredients to help improve body composition through a reduction in body fat.
Often using proprietary formulations, these products typically work through one or more of three key mechanisms:
- Adaptations in metabolism
- Appetite suppression
- Increased energy
The biggest challenge with this class of supplements is that the rapid proliferation of products far exceeds the rate at which scientific study can evaluate the claims—claims that are often wildly overstated and often poorly qualified.
So with that in mind, let’s take a look at Instant Knockout.
About Instant Knockout
Instant Knockout is a fat burner supplement produced by UK company Roar Ambition and launched in September of 2014.
With origins in MMA and fight sports, the Instant Knockout brand is strong and exciting and immediately establishes credibility through association with successful fighters such as Diego Sanchez and John Dodson, and famed MMA coach, Greg Jackson.
Instant Knockout professes to be an ultra-powerful formula—consisting of ten fat-burning ingredients—that has been exhaustively researched and selected to create a cutting-edge fat burner product.
Instant Knockout Benefits
The primary benefits claimed by Instant Knockout are a boosted metabolism, with additional ingredients added to reduce hunger cravings and increase energy levels.
Metabolism is boosted in a number of different ways including increases in the overall rate of calorie burn, improved insulin sensitivity and the opening of specific chemical pathways that help break-down stubborn fat deposits.
Reduces Hunger Cravings
One of the biggest challenges with any form of calorie restriction is managing hunger. Like other fat burner’s such as PhenQ, Instant Knockout includes multiple ingredients to help suppress appetite and reduce hunger cravings.
Fuels Energy Levels
Whenever calories are restricted, we run the risk of falling energy levels. Multiple ingredients included in Instant Knockout are there expressly to help drive-up energy levels and thus support increased energy expenditure.
Instant Knockout Ingredients
You’ve no doubt heard the saying, garbage in–garbage out, and this is especially true with supplements.
At the end of the day, any supplement is only as good as the quality and quantity of the ingredients used in the formulation, and Instant Knockout claims to use the highest quality, natural variant of each of the ten core ingredients.
As an aside, kudos to Instant Knockout for not using any proprietary formulas in the manufacturing of their product. This means we not only have the exact ingredients but the exact amount of each ingredient too. This is crucial in evaluating the likely efficacy of the product.
It’s also worth mentioning that Instant Knockout is made in cGMP and FDA approved facilities in the USA and UK.
Sadly, they’ve excluded the entire vegetarian and vegan markets for their product by opting to use gelatin for their capsules.
|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||**|
|Black Pepper Extract (standardized to 95% PE)||10mg||**|
** Daily Value Not Established
Other Ingredients: HPMC, gelatin, silicon dioxide, magnesium stearate, FD&C Red 40.
Green Tea Extract
Instant Knockout, like other fat burners such as LeanBean, positions green tea extract as the powerhouse nutrient for fat loss in their formulation and make reference to a couple of studies that do show a measurable effect in this regard.
However, as all such references, you can’t take the marketing headlines at face value.
For example, while one such reference cited does indeed show 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—about the same as a grande drip coffee from Starbucks.
It’s also worth noting that individual studies should never be considered as evidence in their own right and that meta-analysis—a holistic review of all the available studies—is the best place to look for statements about efficacy. And where multiple meta-analyses exist, you should always be looking at the most recent review.
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 or its extracts 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.
Cayenne Powder (from Pepper Seeds)
The magic ingredient in cayenne powder is a molecule called capsaicin, and it’s known to have a whole host of medicinal properties both inside and outside of the body.
In the context of Instant Knockout, capsaicin is added to help boost your metabolism, increase insulin sensitivity and help blunt the appetite.
One meta-analysis on capsaicin of energy intake data for supporting weight management suggests that daily consumption of capsaicinoids may contribute to weight management through reductions in energy intake.
Examine.com—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.
Glucomannan is a natural fiber product, usually taken from the root of the konjac plant that contains ~40% glucomannan by volume.
The primary mechanism by which glucomannan is purported to help improve fat loss is appetite suppression. However, 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.
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, speeding up the signals between the brain and the body.
There is good evidence to support caffeine as an energy booster, and a recent meta-analysis of 13 trials also found that caffeine use correlated with improvements to 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 from the caffeine anhydrous (dried), plus whatever level of caffeine is in the green tea extract. However, this total intake is split across the four doses, meaning that every single dose is around 75mg—or one small cup of regular coffee.
In terms of efficacy, the Instant Knockout dosing of 300mg is in line with the literature and resources like Examine.com, with most studies using 4-6mg caffeine per KG of body weight (300-450mg for a 75KG/165lb individual).
However, it’s worth noting that many of the positive effects associated with caffeine are reduced with tolerance. So if you’re a regular caffeine consumer, the benefits of supplementation may be reduced or eliminated for you entirely.
Vitamin B6 and Vitamin B12
These aren’t quite filled in the Instant Knockout product, but in the context of fat loss, it’s close.
For sure, B vitamins are quite literally essential to energy production in the body—it simply does not happen without these crucial vitamins. 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.
They are not going to be doing much in terms of mood or focus either.
For example, Instant Knockout provides about 5mg (250%) of your RDA for B6, and 10mcg (166%) of your RDA for B12. Contrast that with say, Five Hour Energy which has 40mg of B6 (2353%) and 500mcg of B12 (20833%). That’s quite a gap in dosing!
And the reality is that both Instant Knockout and Five Hour Energy contains a solid dose of caffeine—an ingredient that is far more likely to be giving you the boost in mental acuity than the B-vitamins.
Consumed through the diet, chromium is an essential mineral that helps regulate our glucose metabolism and insulin sensitivity.
Instant Knockout lists a number of benefits associated with this trace element, including improved insulin control as well as reduced appetite and food cravings.
But again, in cited studies, Instant Knockout does tend to cherry-pick the positives from these papers, where in fact the clinical evidence is wholly inconclusive. For example, one paper they reference on their website makes the following conclusion very clear:
In conclusion, our meta-analysis suggests a relatively small effect of chromium picolinate compared with placebo for reducing body weight. The clinical relevance of the effect is debatable and the lack of robustness means that the result has to be interpreted with caution.
This position is also supported by other reputable resources that look at the full body of available data, with Examine.com stating the following:
Chromium regulates insulin in the body. It is sometimes supplemented to improve insulin action in the body. When chromium is supplemented by people with normal or elevated chromium levels, no reliable effect is achieved. Besides a mild decrease in fasting glucose, no diabetes-related biomarkers are improved.
Zinc is another dietary mineral that has numerous roles in the body at a cellular level, and there is data to suggest that zinc has a role to play in low testosterone and decreased insulin sensitivity. And Instant Knockout goes on to cite a couple of references that do show some positive effects in one or more groups.
However, as is the case with all such dietary minerals, unless there is a clinical deficiency or confounding medical condition (e.g. diabetes, low testosterone), the effects of zinc supplementation are not often shown to be effective in the general population.
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 so much as they are overstated. And while there will likely be no negative effects of including piperine in the formulation, there just isn’t the scientific data or human studies to support any claims in this regard.
Green Coffee Bean
Green coffee beans are unroasted coffee beans, and despite Instant Knockout claiming they have no caffeine at all, most green coffee beans and extracts seem to have somewhere between 20% and 25% of the caffeine of roasted beans.
Most of the benefits of green coffee extract come from the antioxidant chlorogenic acid, and some studies in mice have shown it effective in helping the body to burn glucose and stored body fat.
However, when we look at the recent meta-analysis of human trials using the green coffee extract as a weight-loss supplement, the results are far less inconclusive:
Conclusion: The evidence from RCTs seems to indicate that the intake of GCE [green coffee extract] can promote weight loss. However, several caveats exist. The size of the effect is small, and the clinical relevance of this effect is uncertain. More rigorous trials with longer duration are needed to assess the efficacy and safety of GCE as a weight loss supplement.
Dosage and How to Take Instant Knockout
Each bottle of Instant Knockout contains 120 capsules and individuals are directed to take one capsule, four times a day.
- One first thing in the morning
- One before lunchtime
- One in the afternoon
- One before the evening meal
This means each bottle of Instant Knockout will last approximately one month.
Claims vs. Reality
As is the case with many fat loss products, Instant Knockout uses some emotive language throughout their web site. 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 their lean, athletic and powerful physique is many hours of grueling strength, conditioning and grappling training, combined with strict adherence to a well-planned diet.
However, I’ll commend Instant Knockout in that they don’t seem to make a lot of grandiose claims about their product, generally limiting the thrust of their claims to statements about the efficacy of the ingredients and formulation.
And while the vital importance of diet and exercise as the foundation of body recomposition is somewhat underplayed, they do state on more than one occasion that Instant Knockout is intended for use in conjunction with a diet and exercise regime.
Lastly, references to scientific journals and studies are frequently provided when specific claims about the effectiveness of an ingredient are made. However, as is the case with all such efforts, the onus remains on the consumer to do their homework and actually look-up and read the referenced papers.
As a result, you’ll frequently find the marketing narrative somewhat more optimistic than was generally inferred in the linked research.
In one such example with Glucomannan and appetite suppression and fat loss, the Instant Knockout website says:
“This is backed up with comprehensive research too. For example, one review of 6 different studies reported consistent short-term weight loss”.
However, the linked paper’s conclusion clearly stated:
“In otherwise healthy overweight or obese adults, there is some evidence that in the short term GM [Glucomannan] may help to reduce BW [body weight], but not BMI [body mass index].”
In short, if you really want to be clear about the proposed claims, you have to be willing to dig-in and do your own research.
Who is it Best For?
Despite a strong association with professional athletes and fight sports, the Instant Knockout product is targeted at anyone that wants to drop body fat and improve their physique.
And despite the overtly masculine theme of the brand, Instant Knockout goes out of its way to speak to the suitability of their product for females, dedicating an entire section of their website to women.
The best results will undoubtedly be seen by those following a calorie-controlled diet and robust training schedule—something that Instant Knockout speaks to in a couple of places in their marketing and terms and conditions.
In fact, the opening question in the Instant Knockout FAQ positions the product as a bodybuilding supplement. So keep that in mind if you were hoping to just pop pills and see great results.
Instant Knockout Safety and Side Effects
The specific ingredients used in Instant Knockout are all-natural and presented in quantities that appear to be safe and well evaluated in the medical literature. However, this doesn’t mean there are no risks associated with taking the product, as no clinical trials have been performed using this specific formulation.
Due to the use of stimulants like caffeine, the product is recommended for adults only. And Instant Knockout carries all the typical disclaimers that those with medical conditions or who are taking medication should be seeking advice from their doctor before using the product. It is also not recommended for women that are pregnant or nursing.
You should also check that you have no allergies or sensitivities to any of the listed ingredients.
Instant knockout contains a significant dose of caffeine in the form of caffeine anhydrous (powdered) and green tea leaf extract.
It’s impossible to know how much caffeine is in the green tea leaf extract, as the amounts vary greatly across brands and methods used to extract the powder.
At a minimum, there is 300mg of added caffeine in the formulation, the equivalent of roughly 2 cups of coffee. Of course, this equivalence varies significantly depending on the coffee bean, preparation, and size of your cup!
For example, one grande cup of Starbucks Pike Place contains 310mg of caffeine.
Consequently, the packaging makes a clear warning not to consume any other products that contain caffeine while taking Instant Knockout.
Caffeine can make some people feel anxious or agitated, and an excess of caffeine can lead to headaches and stomach upset. Caffeine can also interfere with sleep when consumed too close to bedtime. And given the dosing schedule for Instant Knockout requires you take the last dose around 5 pm, those sensitive to caffeine could experience difficulty falling and staying asleep.
Where to Buy + Costs
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 online at https://www.instantknockout.com.
US pricing as of the date of this article is as follows:
- One Bottle — $59 + $7.95 shipping
- Two Bottles — $118 (qualifies for free shipping, saving $7.95)
- Three Bottles — $185 (free shipping plus one free bottle)
Buying the three bottle stack nets you a fourth bottle for free, bringing the total monthly cost of Instant Knockout down to $46.25 — a saving of over $50 on the price of four individual bottles.
Instant Knockout offers a 90-day money-back guarantee to consumers.
Directly from the website homepage:
“We insist the risk is on us, so simply try Instant Knockout for 90 days and if you do not see any results then we will gladly refund your money.”
And at face value, this seems like a no brainer. Simply try the product and if you don’t like your results, request a refund.
However, the guarantee is far from unconditional and the terms and conditions state the following:
We are confident that you will be satisfied with your purchase of Instant Knockout. As a result, we will refund your purchase if you haven’t experienced any results.
Please note that Instant Knockout is a supplement to an already good exercise and diet plan.
Before requesting a refund, you must have:
– Taken Instant Knockout for a full 90 days as instructed by the packaging.
– Performed regular exercise.
– Eaten a consistently healthy and calorie-controlled diet.
This guarantee is only available for consumers who have purchased 3 or more boxes. The money guarantee only applies to your first order.
Key things to note here:
- It’s not only that you have 90 days to request a refund, but you also have to buy and use three months of the product to qualify.
- Instant Knockout requires that you perform regular exercise and eat a consistent, calorie-controlled diet. How does Instant Knockout intend to verify or enforce this condition of the guarantee?
- The guarantee only applies to your first order. So unless you buy the three-month stack up-front, it’s not clear that the subsequent individual orders would qualify for the refund.
It also doesn’t take much Google-foo to find clear evidence from consumers that they are struggling to get the onerous return policy honored by Instant Knockout.
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 listed for more than $40.
From this perspective, it suggests that Instant Knockout is at best not cheap.
The Bottom Line
So we’ve arrived at the
million-dollar $185 question—should you buy the Instant Knockout supplement?
Does Instant Knockout Work?
From the ingredients list, it’s a solid maybe.
There certainly is some evidence that each of the ingredients used has been shown to support one or more of the claimed benefits of boosted metabolism, increased energy or reduced hunger cravings.
However, when you dig in and really look at the evidence to support the claims, it comes-up a little thin. Especially in human trials or when reviewing ALL of the available research with meta-analysis.
What Are Consumers Saying?
The Instant Knockout website presents a very convincing collection of user reviews and testimonials. And the product does have some significant celebrity endorsements from respected fighters and coaches alike.
However, it’s also not hard to find plenty of reviews from unhappy users that have not seen positive results, commenting that they neither felt or performed differently, nor achieved any significant weight loss from using the product.
But in truth, this is almost always going to be the case as individual results and expectations do vary wildly—especially when it comes to diet, exercise, and body composition.
So again, a solid maybe?
Should I Buy Instant Knockout?
It should be clear to you that dropping body fat and building an athletic, muscular physique requires extreme discipline with both diet and exercise.
The Instant Knockout FAQ even positions its product as a bodybuilding supplement and makes clear throughout the website (including the terms and conditions) 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 sustained calorie deficit. Can Instant Knockout help you sustain achieve that through elevated energy levels and some improvements to satiety and hunger management?
So here’s the bottom line: A supplement like Instant Knockout could provide some added support on your fat loss journey, and if you have the cash to spare and want to give it a try, it might help you achieve the results you want. But if funds are tight, save your money and double-down on nailing your training and diet.
 – Int J Obes (Lond). 2009 Sep;33(9):956-61. DOI: 10.1038/ijo.2009.135. Epub 2009 Jul 14. The effects of green tea on weight loss and weight maintenance: a meta-analysis. Hursel R1, Viechtbauer W, Westerterp-Plantenga MS.
 – Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-. [Effect of green tea or green tea extract consumption on body weight and body composition; systematic review and meta-analysis] 2014. Available from: https://www.ncbi.nlm.nih.gov/books/NBK231811/
 – 2014 Feb;73:183-8. DOI: 10.1016/j.appet.2013.11.005. Epub 2013 Nov 15. Could capsaicinoids help to support weight management? A systematic review and meta-analysis of energy intake data.
 – J Am Coll Nutr. 2014;33(1):70-8. DOI: 10.1080/07315724.2014.870013. The efficacy of glucomannan supplementation in overweight and obesity: a systematic review and meta-analysis of randomized clinical trials. Onakpoya I1, Posadzki P, Ernst E.
 – Crit Rev Food Sci Nutr. 2019;59(16):2688-2696. DOI: 10.1080/10408398.2018.1507996. Epub 2018 Oct 18. The effects of caffeine intake on weight loss: a systematic review and dose-response meta-analysis of randomized controlled trials.
 – Int J Obes Relat Metab Disord. 2003 Apr;27(4):522-9. Chromium picolinate for reducing body weight: a meta-analysis of randomized trials. Pittler MH, Stevinson C, Ernst E.
 – Onakpoya I, Terry R, Ernst E. The use of green coffee extract as a weight-loss supplement: a systematic review and meta-analysis of randomized clinical trials. Gastroenterol Res Pract. 2011;2011:382852. DOI:10.1155/2011/382852