Top 5 Best Fat Burner Supplements 2021


Looking to trim down and retain hard earned muscle? Here’s our top 5 fat burners list (now updated for 2021)! If you already aren’t familiar with them, so-called fat burners are food supplements that help support the loss of weight by raising metabolism, reducing cravings and helping the body use more fat as fuel.

Our top fat burners have all been roadtested for weeks to ensure they’re completely clear of any risky or synthetic ingredients. We base our list on:

  • Fast, lean physique results
  • 100% natural formula
  • Clean energy
  • Appetite reduction
  • Healthy mood & focus
  • Long-term safety
  • Company trust

The following fat burners also have the ability to optimize your workouts by boosting energy and focus, which can be especially useful during caloric restriction.

In the past year alone, we’ve researched and tested over 35 most popular fat-burning supplements, comparing them against each other to see which is the best value. The result of our search has allowed us to present the top 5 fat burners on the market right now.

Instant Knockout

• 100% natural with no fillers

 • Endorsed by pro athletes and trainers
• Bulk-buy deals

• Muscle protecting for toning

• Helps burn fat as part of a healthy lifestyle

• Excellent reviews
• Website:

Hunter Burn

• For busy men 35+

• Made with premium-quality thermogenics
• Strong hunger control
• Natural, clinically backed formula
• Potent ingredient dosages

• Luxury brand

• Website:


• Pure CBD isolate

• Works to enhance your training
• cGMP approved and safety inspected

• Supports appetite control
• May improve sleep quality
• Website:

Burn Lab Pro

• The best stim-free fat burner

• 100% transparent
• Used by #1 Ranked UFC Bantamweight Athlete
• Natural and thoroughly researched

• Website:

Fighters Core

• Award-winning formula

• Boosts metabolism for higher calorie burn
• Backed by academic research
• 100% natural
• Website:

#1 Instant Knockout – Best Overall

“The best thermogenic fat burner. Completely safe and natural with fast results.

Instant Knockout CUT

Instant Knockout is an innovative, cool looking fat burning supplement that can help you shred weight relatively fast. It was originally developed for MMA fighters by Roar Ambition, a specialist company based in the UK but operating worldwide.

This product boasts excellent reviews and some of the best ratings out of any fat burner. Both men and women have been using to get leaner and keep the weight off in a safe and sustainable way.

Effects that make Instant Knockout the best thermogenic:

  • Significant levels of fat loss in 5-6 weeks
  • No hunger cravings
  • Preserves lean muscle tissue
  • Maintains high energy levels and focus during the day

Ever since its release in 2012, Instant Knockout’s makers have constantly talked with nutritionists and pro athletes to keep their formula updated.

Specifically, Instant Knockout gets an update every 6-12 months, based on the latest scientific findings.

We like this – it tells us we aren’t getting a product that lives on its past glory, but one that’s arguably still number 1 after all these years.

See Instant Knockout for yourself here:

Our Results

Cutting weight with IKO was surprisingly smooth and felt easy. It starts working almost immediately.

The first change we noticed was a reduction in our appetite, followed by a good clean source of energy that lasted throughout the day despite being low on calories.

Our Instant Knockout CUT box.

After about 3 weeks we started to notice changes in physique and around the belly, which was a bit unexpected!

This is the fastest fat burner we’ve tried.

After those initial 3 weeks, the results slowed down a bit, but we did slip up here a few times. That said, if you keep going for 2-3 months with this product you’ll see some pretty impressive differences in your physique compared with when you started.

One annoying drawback was that it’s only available directly from the manufacturer’s website, and the price is a bit high, but it’s kind of expected from a product of this quality.

Four capsules per day might seem annoying as well, but keep in mind that this will prolong the fat burning effects throughout the entire day, meaning you won’t have any ‘downtime’ in effects between doses.

Three months cutting with IKO, 3 day a week training, and a fairly clean diet.

See more Instant Knockout Testimonials here:

The Good:

  • 10 healthy and all-natural ingredients
  • Provides long-lasting, clean energy
  • Effective fat burning
  • Suppresses cravings
  • No hidden ingredients or proprietary blends
  • Large discounts when you buy in bulk
  • Available worldwide
  • Excellent reviews

The Bad:

  • Premium price when buying just 1 box
  • Only sells directly from Instant Knockout’s website
  • Not for those with extreme caffeine sensitivity

Visit Their Website:

#2 Hunter Burn – Best Fat Burner for Busy Men

A high-end scientific fat burner specifically designed for men over 35.

Hunter Burn Fat Burner

Hunter Burn is a highly targeted fat burner that caters to a specific audience – premium, high-achieving men who need a supplement that will help them feel good and look great.

If you’re looking for a fat burner that delivers some of the industry-leading ingredients in big clinical doses, then get your hands on a supply of Hunter Burn.

It contains a generous amount of white kidney bean, matcha tea, and vitamin D3 to support muscle-building, performance, and fat burning.

While it comes at a premium price tag, Hunter Burn doesn’t compromise in any department.

It will help you:

  • Improve daily mood and mental sharpness
  • Target stored fat with matcha tea
  • Activate thermogenesis with Cayenne
  • Suppress cravings with white kidney bean
  • Support immunity with vitamin D

Our Thoughts on Hunter Burn

This is a product with a tried and tested formula. You should experience a lift in focus, mood, and energy levels shortly after taking Hunter Burn.

We saw the first visible improvements after 4 weeks of use. We think it will work extremely well if you combine it with calorie deficit and regular exercise.

Burn by Hunter Evolve - Our Bottle

Effects over 1 month:

  • A good amount of daily energy, without the jitters
  • More motivated to hit the gym, and better performance with weights
  • Better quality sleep
  • Improved ability to sustain focus and deep work
  • Solid amount of fat loss (comparable to Instant Knockout)

While unexpected, some of our team members also reported an increase in libido, which is thanks to vitamin D. When you think about it, this is not really a surprise – about 1 billion people worldwide are deficient, and one of the symptoms is diminished sex drive.

At the end of our trial, we tried combining Hunter Burn with ShredCBD. While obviously expensive, let’s just say it was an incredibly fast fat loss experience.

The only complaint we have about Hunter Burn is the price. We understand that it’s made to deliver maximum quality, but some folks might want a cheaper option. With that said, Hunter Burn is definitely worth the money if you can afford it.

The Good:

  • 6 potent and high-quality ingredients
  • Generous dosages (5000IU of vitamin D3)
  • Scientifically backed
  • 90-Day Guarantee

The Bad:

  • Expensive
  • Only found on the Hunter Revolve Website

Visit Website:

#3 ShredCBD – The Best CBD-Based Fat Burner

shred cbd number 1 fat burner

ShredCBD is an effective, side-effect-free solution to burning unwanted fat and feeling leaner. CBD plays a crucial role in your body’s endocannabinoid system (ECS). Which is why supplementation works so well. It’s completely different from any other product on offer right now.

CBD helps you shred down in 5 different ways:

  • Triggers fat ‘browning’ to help the body use fat as fuel
  • Promotes insulin sensitivity to prevent weight gain
  • Significantly reduces cortisol, a stress hormone linked to fat accumulation
  • Improves mood and sleep quality
  • Interacts with brain’s ECS receptors to influence appetite and reduce calorie consumption

CBD in ShredCBD comes as pure hemp isolate, meaning it’s under 0.1% THC, non-psychoactive (doesn’t make you high), and completely legal in the USA.

Green tea and Garcinia Cambogia are added to augment the fat oxidation effects of CBD. Plus, they provide antioxidants to boost your immune system and keep you healthy.

What makes ShredCBD stand out from the crowd is that it shows amazing potential not just for fat loss, but also sleep, mood – and overall quality of life by extension.

Our Results

This is a high grade supplement that even after a couple of days led to some apparent changes in focus, mood and appetite.

In terms of weight loss, you can expect to see results after around 30 days, especially if you use ShredCBD’s power to exercise and focus on a whole-foods diet.

Effects over 2-5 weeks:

  • Good fat loss (as much as any fat burning supplement)
  • Reduced appetite
  • More energy
  • Better sleep and focus

ShredCBD has no dodgy stimulants in it either, so there’s no risk of side effects or insomnia.

The Good

  • A potent 40mg of pure CBD Isolate per day (1200mg in the whole bottle).
  • CBD alone delivers more benefits than most fat burner ingredient blends.
  • 50mg of Garcinia Cambogia and Green Tea to aid further weight loss.
  • Free Fast Shipping across the USA.
  • Free 24-page weight loss e-book (apparently worth $10).

The Bad

  • Only available in the USA
  • Premium price due to the high manufacturing cost of CBD isolate
  • You can only get it directly on the official website

Visit Their Website:

#4 Burn Lab Pro┬« – Best Stim-Free Fat Burner

Extremely clean, standardized formula with some of the most effective ingredients on the market.

Burn Lab Pro’s patented, stim-free formula is extremely light, yet it’s so effective at burning fat that it can rival any caffeine-based weight loss pill.

Free of caffeine, GMOs, cheap ingredients, fillers, or harmful chemicals of any kind.

In our opinion, Burn Lab Pro is the best fat burner if you don’t like the effects of stimulants and want something lighter for long-term fat loss support.

Don’t get us wrong; other fat burners are higher on this list for a reason – they work, and they work fast. However, if you want cleaner effects without the caffeine sensitivity issues, get your hands on a supply of Burn Lab Pro.

The ingredients

Burn Lab Pro’s vitamins and minerals are cultured on probiotic bacteria and yeast using the unrivaled NutriGenesis┬« nutrition technology. This creates a food-identical nutrient with all of its essential cofactors – making it easy for your body to absorb and utilize.

Burn Lab Pro contains the essential trace mineral Chromium, which will regulate your blood sugar levels and curb cravings. Cayenne pepper is a fiery spice that will kickstart your metabolism and make you burn more fat as a result.

You can see the ingredients and their relevant clinical research on Burn Lab Pro’s website here:

Dosage, price, and final thoughts

Dosage instructions: 3 capsules spread evenly throughout the day, with a full glass of water (with or without food).

Burn Lab Pro uses patented ingredients, and so it naturally costs more than some of its competitors – $59 per month’s supply.

However, buying the 3-month supply package gets you 1 extra bottle of Burn Lab Pro for free as well as free worldwide shipping. Breaking it down, Burn Lab Pro costs only $1.48 per day when you buy the 3-month package.

According to people at Opti-Nutra, Burn Lab Pro is perfect for those who exercise on an empty stomach, also known as ‘fasted’ training. With 90 capsules per bottle, you’re getting a continuous supply of fat-burning ingredients that will ensure you get the best results. If you can afford it, you’ll definitely be getting your money’s worth with this one.

Visit Burn Lab Pro’s Website:

#5 Fighter’s Core – Athlete’s Favorite

We said; The best fat burner for protecting muscle on a calorie deficit.

Developed in late 2020, Fighter’s Core is a fat burner from specialists at PFX Labs. It’s designed for 30-day Pro-cut and consists of 8 highly focused natural ingredients.

Fighter’s Core works by:

  • Blocking enzymes that break down muscle tissue – maximize ROI from your dieting and training
  • Increasing muscle protein synthesis – more muscle, faster metabolic rate
  • Stimulate energy production – directly through caffeine and also by optimizing your mitochondrial cells
  • Naturally promotes hormonal balance in the body – less of the stress hormone cortisol, more of the androgen hormone testosterone

Dosage instructions: 3 capsules spread evenly throughout the day, with or without food.

Who is Fighter’s Core for?

Preventing muscle loss while cutting weight can be a daunting task for any athlete, let alone a natural bodybuilder.

If you’re someone who needs to make sure you retain as much muscle as naturally possible, then look no further than Fighters Core. This supplement is specifically designed for athletes who want to get the most from their diet and training.


The entire ingredient profile of Fighter’s Core is transparent; you won’t find any proprietary blends or other marketing gimmicks on the label. It’s also a very clean formula that’s manufactured in the USA in cGMP approved facilities.

Featuring the likes of HMB calcium which protects muscle tissue from breakdown, Forskolin which increases the body’s innate fat-burning molecule cAMP, and Theacrine to boost your mental focus and reduce cravings, Fighter’s Core has really nailed it when it comes to tackling weight loss from different angles.

Fighter’s Core also has plenty of caffeine anhydrous, which, unless you’re very sensitive to it, is a great way to maximize your energy levels.

Price and final thoughts

Fighters Core costs $49 per month’s supply, but you can get solid discounts when buying multiple bottles. We appreciate it’s quite expensive, which is one of the very few downsides of this supplement and the reason why it didn’t make it higher on this list!

That said, Fighter’s Core is the winner of Generation Iron’s 2020 Supplement Awards in the fat burner category, and continues to be the best fat burner for anyone who considers themselves an audience for in 2021, too.

Visit Fighter’s Core Website:

Our Conclusion

We tested, rated and ranked our top 5 fat burners carefully based on criteria such as:

  • Clinical evidence
  • Potency
  • Safety

We recommend ShredCBD for men and women who like stim-free products and want other benefits to their daily life in addition to weight loss. Such as improved sleep and better mood.

Instant Knockout is our #1 thermogenic supplement for focus, energy and fat burning in the shortest space of time possible (naturally).

We recommend the top product, but generally speaking, all of them can deliver you the results you’re after.

Click to read my ShredCBD Review!



  1. Hi, I just read your article and it was a great read! I actually ended up ordering the Hunter Revolution Burn and the Shred CBD to combine them as you mentioned. My question is did you take them both as suggested or did you adjust it?

    • Hi Theodore,

      Thank you. We took both supplements according to the manufacturer’s recommendations. So 1 capsule, twice per day for ShredCBD, and 2 capsules three times per day for Hunter Burn. One person from our team has caffeine sensitivity so they only took 2 capsules of Hunter Burn, once per day.

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