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Optimum Nutrition Burn Complex Review

Posted on October 8, 2019

Optimum Nutrition Burn Complex ReviewDividerimage


The Burn Complex product range consists of two functional powders and a protein powder, all of which are designed to assist with burning fat. These are recent additions to the ever-expanding range of innovative Optimum Nutrition products.


When it comes to fat burners, you’ve probably encountered just about every claim imaginable. In their subtle way, products labels and advertising tell us just how amazing and immediate your results are going to be.


Understandably, these claims can capture our interest and provoke thought over what could be. What would life be like if we weighed 10 or 20 kilograms less, with self-confidence reaching record levels? Surely this would be followed by some kind of life transformation and an ever-lasting wave of happiness and content …


With a market practically bursting at the seams with all sorts of weight loss nutritional powders, liquids and fortified proteins, it’s pretty easy to quickly become confused.


Are these label claims actually verified? Who do we trust?


Heavy-handed sales tactics and way over-the-top marketing techniques have turned simple nutritional formulas into supposed life-resurrecting must-have products.


To be this good, surely these products must contain molecules encouraged into existence by nothing other than magic, perhaps by the hand of Gandalf or Harry Potter.


And when the results don’t match the claims, it’s easy to become frustrated and disillusioned. Even conclusions drawn from scientific research can contradict each other. After all, a researcher’s conclusions are dependent on so many variables, such as study design, mathematical analysis of the results, dosage, duration and quality of the nutrient, food or herbal medicine.


And then we have to consider who’s funding the research …


This isn’t to say that quality supplements don’t have a place in helping us achieve health, body composition or performance outcomes. There’s plenty of ethical scientists, quality research and sports nutrition and wellness companies that put ethics and efficacy on a high pedestal.


In fact, the Burn Complex range helps us become a little more optimistic about sports nutrition supplementation. The team at Optimum Nutrition have clearly done their research in formulating these underrated products, identifying nutritional compounds backed by some interesting scientific studies.


Optimum Nutrition Burn Complex Caffeine-Free

This product is a 100% caffeine-free option, ideal for anyone training late at night, who is caffeine sensitive or already has a high caffeine intake. After all, those triple-shot espressos do add up!


Burn-complex-caffeine-free.jpgThough caffeine itself is a helpful fat burning aid, this product delivers additional metabolic boosters. One in particular functions in a similar biological way to caffeine.


Acetyl L-Carnitine

Often one of the most irritating parts of weight loss products is that they deliver sub-optimal dosages. For instance, the therapeutic dosage window for Acetyl L-Carnitine is considered to be around 1g to 2g per day for adults.


Have you ever read a nutrition label more closely when you got home, only to discover there is a “c” between the “m” and the “g” that you think shouldn’t be there?


For example, you thought there was enough active ingredient in each serve, only to realise that the nutrient is listed in micrograms (mcg) instead of milligrams (mg). That is to say, 1,000 times less than an ideal dosage!


Fortunately, ON Burn Complex non-stim delivers a solid 1.5 grams of the acetylated form of L-Carnitine. The difference between L-Carnitine and Acetyl L-Carnitine is that the latter passes through the blood-brain-barrier, offering another set of potential benefits.


We may only be scratching the surface when it comes to understanding what Acetyl L-Carnitine can do for human health, especially regarding fat loss, enhancing energy synthesis, boosting antioxidant status and improving the physical condition of the aging adult.


A fascinating review article published by Nutrients in 2018 highlighted that L-Carnitine supplementation can increase muscle mass, whilst decreasing body weight in older adults 1. This indicates reductions in fat mass.


It was also noted that L-Carnitine supplementation helped to reduce physical and mental fatigue, reduced delayed muscle soreness and improved blood flow to muscle tissue. These are quite a lot of unique benefits from one dipeptide.




It’s important to note that many of the benefits of L-Carnitine in older age may be due to improved muscle energetics, as muscle carnitine levels decrease with age.


When it comes to fat-burning, carnitine plays a quite intrinsic role in the human body, and is responsible for shunting long-chain fatty acids into the mitochondria for energy.


A comprehensive review article published by Obesity Reviews in 2016 indicated that Carnitine supplementation led to an additional 1.33kg of extra weight loss compared to placebo 2.


This puts Acetyl L-Carnitine in the order of magnitude of helpful adjunct to weight loss. Is it an absolute miracle maker? Certainly not. If you’re after miracles, these can only be achieved through a shift in mental attitude and changing the way you live, plus a decent helping of time.


Reality can be a cold slap in the face by an overly large hand, right? However, it’s better to face facts now than have your expectations crushed after many weeks or months of diligent supplementation.


Chilli, Cayenne and Capsaicin: One and the Same?

Just as the main active compound in turmeric is curcumin, chilli contains a fiery plant chemical called capsaicin. Capsaicin is actually one of the many capsaicinoids found in chilli plants.




Cayenne Pepper is a type of chilli that contains plenty of heat-inducing capsaicin. And why do we want more heat, especially during a scorching Australian summer?


Because capsaicin does special things to our metabolism, a by-product of which is heat.


The prestigious Lancet published an article all the way back in 2001 which examined the effects of consuming capsaicin containing foods on obesity 3. The researchers concluded that capsaicin was associated with a lower prevalence of obesity.


Though epidemiological (population-based) research results can be difficult to interpret, clinical trials have been conducted using capsaicin and placebo in order to study their effects on fat loss more closely.


One such study examined chilli supplementation and placebo in 40 women and 40 men over 12 weeks, with results indicating an improvement in abdominal fat loss 4. The researchers stated that the fat loss was close to significant, which simply means the numerical cut-off point that needs to be reached to call the results statistically significant was narrowly missed.




This concept can be compared to the expiration date on food. At a minute before midnight it’s safe to eat, yet two minutes later … expired. Of course, we know that teams of pathogenic bacteria didn’t wait until the stroke of midnight to reveal themselves. The freshness of a packaged food is on a constant downward trend after its creation. An expiration date simply makes things easier for the consumer.


Statistically-significant and fresh, non-significant and expired. There’s always a grey area in between. But I’m not suggesting for a minute that you consume expired foodstuffs—disclaimer alert!


Another research article showed that capsaicin supplementation slowed weight regain after modest weight loss 5. Though this doesn’t exactly sound jump-and-click-your-heels-together amazing, it still highlighted capsaicin’s fat burning power.


Finally, in 2017 the Journal of Basic Clinical Physiology and Pharmacology published an article stating that chilli supports fat metabolism and thermogenesis by triggering the sympathetic nervous system and enhancing insulin control 6.




Stimulants, like caffeine, also trigger the sympathetic nervous system, which is why they are believed to assist with fat burning and weight loss.


Because this is a caffeine-free products, you won’t notice any stimulant effects, which you might rely on if you are using this as a pre-workout. And though the caffeine version will have slightly better fat-burning potency, this product is a quality non-stim variety. 


This product also contains L-Theanine, Green Tea Extract and a B Vitamin complex, which assist with energy, fat-burning and mood. These ingredients will be covered in more depth in the paragraphs ahead.


This all puts Optimum Nutrition Burn Complex Caffeine-Free in good standing as a helpful thermogenic assistant. There’s no substitute for a quality diet, lifestyle and exercise program, but this product is as good as it gets when it comes to a thermogenic aid that won’t have you climbing the walls at night.


Smart nutritional products like this one from Optimum Nutrition do help to take the edge off, making your body composition goals easier to attain and also maintain once reached. 


Optimum Nutrition Burn Complex with Caffeine

If you like to hit the gym with some caffeine-containing thermogenics circulating through your veins, then this is the product to get the job done.


The difference between the two varieties of Burn Complex powder is that the caffeinated version contains guarana plus pure caffeine. All other active ingredients are identical.


Guarana and Caffeine

Burn Complex caffeinated contains 250mg of caffeine per serve, as well as Guarana Seed Extract. Guarana is a climbing plant native to the Amazon basin in Brazil, an area well known for its rich fertile soil.


Guarana seed is a natural source of caffeine. In fact, the seeds of this climbing plant contain around 4 times the amount of caffeine as coffee! In addition, research shows that there are in fact other natural plant chemicals in guarana seed, apart from caffeine, that have a stimulant effect as well 7.


Based on this, each serve of Burn Complex ON Caffeinated delivers approximately the stimulant effect of 3 standard cups of coffee. Compared to your average pre-workout, you could say this it still about smack-bang in the middle of the road when it comes to potency.


If you don’t often take herbal stimulants, caffeine or coffee, the moral of the story here is take it easy. Rome wasn’t built in a day, nor a month. Start on a ¼ serve, taken before lunch, and see how you go. Or just go stimulant-free.


The Guarana, along with Acetyl L-Carnitine, Green Tea, Caffeine and Cayenne in ON Burn Complex Caffeinated all offer a nice synergistic fat-burning effect to complement your exercise, quality meals and healthy lifestyle 8.


B Vitamins

B Vitamins are well known as anti-stress and energy promoting nutrients, sold in capsules, tablets, liquid and even powder form. Burn Complex Caffeine contains B1, B2, B3, B6, B12 and Folic acid.


Though the quantities of each of these vitamins does not reach that of a B complex, excluding folic acid at 300mcg per serve, it does cover some of your basic needs for these nutrients.




This product can be substituted for a pre-workout due to its caffeine and Acetyl L-Carnitine content. It will deliver a decent energy hit, depending on your sensitivity just like a standard pre-workout, with ingredients to promote fat burning.


Acetyl L-Carnitine is in fact a fantastic nutrient to take before exercise, no matter your performance or body composition goals. Not only does it promote fat-burning, but it can also enhance energy levels, reduce muscle soreness, improve mood and focus, and in older adults it has been shown to increase lean body mass 9,10,11.


If your training goals are more related to strength, power and muscle size, you will be better off using Gold Standard Pre-Workout. This standard pre-workout delivers specific amino acids, like creatine, to enhance explosive power and muscle volumisation.


Optimum Nutrition Burn Complex Protein Powder

No fat-burning thermogenic range could ever be complete without a quality protein powder! Optimum Nutrition have spared no expense in delivering a bioavailable dairy protein, loaded with the common ingredients from their Burn Complex range.


9F22CEDA-85AA-4602-8D33-5AB58ABAC3FC__77439.1552105683.1280.1280.jpgGreen Tea

Green Tea is one of the quintessential natural thermogenics, offering a wide range of benefits helpful to overall health. It is derived from the Camellia sinenses plant, as are the others teas Assam, black and oolong.


In the field of Herbal Medicine, Green Tea is often prescribed for a number of reasons, as it offers anti-viral, antioxidant, anti-bacterial, anti-cancer effects and more. Research has also clearly established a place for this ingredient as a valid fat-burner.


Green tea contains a range of natural plant chemicals called polyphenols. These interesting compounds offer a range of benefits, with one in particular gaining more than its fair share of scientific attention: EGCG.


Epigallocatechin-3-0-gallate (easier to say EGCG) is believed to be the main fat-burning phytochemical in Green Tea. Research has so far shown that Green Tea increases exercise-induced abdominal fat loss and helps us burn fat faster than can be explained by its caffeine content 12.


An interesting research paper published in 1999 by the one-and-only American Journal of Clinical Nutrition (yes, I’m a fan) showed that supplementation with this tea leaf actually increases your 24 hour energy expenditure 13. This is good news for tea lovers and anyone ready to hook into Optimum Nutrition’s Burn Complex range.


Though it would have been nice to see a standardised extract used throughout the Burn Complex range, which specifically indicates the EGCG and total polyphenol content, this ingredient will deliver some benefit to help you move in the right direction—faster.



L-Theanine is an amino acid that is not incorporated into human body protein structures, though it does have a neurotransmitter effect in the brain. Originally discovered in Green Tea back in 1949, L-Theanine was later found in various fungal species.


Isn’t it interesting that 70 years later, we are establishing a role for this nutrient. It makes you wonder what fascinatingly mysterious nutrients scientists are uncovering today that will be popular 100 years from now …


Anyway, this is an incredible digression from the topic at hand!


This specialised amino acid has been researched reasonably well over the last couple of decades, with studies consolidating a role for it as a biological calming agent. L-Theanine is able to stimulate relaxing alpha brain waves, which assist in the management of mild stress and anxiety 14,15.


This effect may be mediated by blocking a powerful stimulatory neurotransmitter in the brain called glutamic acid 16.


L-Theanine has become a popular inclusion to a wide range of sports nutrition and wellness supplements. And it might seem counterproductive and somewhat counterintuitive taking a relaxant when you’re about to engage in vigorous exercise …


However, we can’t forget that Burn Complex ON Protein does contain caffeine. Though caffeine is a great ergogenic and thermogenic aid, it can trigger some unwanted side effects, like jitteriness and scattered focus.


For this reason, caffeine accompanied by L-Theanine can be even more potent. The caffeine delivers the physical stimulation and drive to forge ahead, while L-theanine mops up neuronal side-effects in the brain.


Optimum Nutrition Burn Complex Protein contains 100mg of caffeine per serve, which is equivalent to approximately 1 standard cup of coffee.


Protein Powders and Weight Loss

So why would we use a protein powder on a weight loss or even a maintenance program? Aren’t we just guzzling unnecessary energy that we’ll invariably have to burn off?


man-running.jpgThat’s the beauty of high quality bioavailable protein. Much of the natural energy inherent within the molecule is stored or converted. If you’re keen, let’s dig a little, as it’s quite a complex subject.


Protein has a lot more fat-burning power than carbohydrates and fats. This thermogenic or heating effect, which is a sign of metabolic activity, is likely the result of increased protein synthesis.


Protein synthesis is the process of repairing or building lean muscle and many other protein structure and compounds in the body, such as those found in bone, organs and skin.


This protein-synthetic protein-food-related heat-effect was suggested as far back as the 80s, in an article published by the International Journal of Obesity 17.


So if you’re not a scholar of protein and are a little confused here—completely understandable. To summarise: we consume quality protein through food or drink, which triggers protein synthesis.


Because protein synthesis is an energy-demanding activity, a greater amount of heat is created.


In part, this protein synthesis is responsible for repairing and building lean muscle mass. Therefore, much of the energy contained within high bioavailability protein is actually stored as lean body mass and other important body proteins, which is really good.


This is why many companies selling branched chain amino acids and essential amino acid formulations claim their products are zero calorie. Though this statement is certainly a stretch, much of the essential amino acids will not need to be burnt as fuel, and instead will be used to rebuild, repair and maintain our body (more so true for a quality EAA formulation).


This chapter isn’t designed to remove all inhibitions when it comes to guzzling litres of delicious flavoured protein shakes multiple times daily! The body’s capacity for protein synthesis is certainly not infinite.




And overloading with too much protein can create digestive disturbances, and leave us feeling washed out and ready for a nap, rather than inspired to hit the gym or catch up on some energy-expending weekly jobs, like washing the car or mowing the lawn.


Going overboard on protein also tends to cause us to miss out on other important nutrients in our diet, like fibre, low glycemic index carbohydrates and beneficial fats.  


However, one or two protein shakes daily each delivering 20 grams of dairy protein is perfectly fine for most people, particularly when you’re engaging in an exercise program.


These shakes also serve the incredibly important purpose of preserving lean muscle mass during weight loss programs. This helps to reduce the risk of rebound weight gain 18.


What Makes the Burn Complex Range Different?

The Optimum Nutrition Burn Complex range is unique and rich in ingredients supported by clinical trials and other research. It also offers an option for the caffeine sensitive. If you are after a caffeine free protein to supplement during a weight loss program, Gold Standard 100% Whey Protein will be fine.


Though the B vitamin potency may be less than effective, and the grade of the Green Tea is perhaps lacking, overall the ingredient selections and disclosed dosages should prove enough to gently nudge you in the right direction on a weight loss or maintenance program.


With classic flavours like Lemon Lime, Grape and Strawberry Kiwi, these drinks go down well on ice or mixed in cold water. A refreshing beverage can really take the edge off a solid training session when, realistically, you’d prefer to be lounging in front of your television with a bag of Doritos.





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  14. Sarris J et al. L-theanine in the adjunctive treatment of generalized anxiety disorder: a double-blind, randomized, placebo-controlled trial. Journal of Psychiatric Research. 2019 Vol 110 p.31-37
  15. Nobre AC et al. L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pacific Journal of Clinical Nutrition. 2008 Vol 17 p.167-168
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  18. Johansson K et al. Effects of anti-obesity drugs, diet, and exercise on weight-loss maintenance after a very-low-calorie diet or low-calorie diet: a systematic review and meta-analysis of randomized controlled trials. American Journal of Clinical Nutrition 2014 Vol 99;1 p.14-23

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