You see fat burners everywhere. Whether you're looking to drop some pounds and maintain a healthy weight or looking to lean out for a competition, they can come in handy—no questions asked.
But when you look at the ingredients of most fat burners, you'll often find a long list—natural or not—that claim to rev metabolism, burn calories, melt fat away, and fuel better performance.
And while a fat burner may seem like the latest and greatest addition to your supplement stack, what cost do all these benefits come at?
Can fat burners damage your liver?
If you're new to the realm of fat burners, we're going to explore what you need to know about the safety and side effects of the most popular fitness supplements around. What to avoid, what to look for, and if fat burners affect your liver or put it at risk.
What Are Fat Burners and Why Use Them?
Fat burners are a class of nutritional supplements that claim to acutely increase fat metabolism or energy expenditure, impair fat absorption, increase weight loss, boost fat oxidation during exercise, or cause long-term adaptations that promote increased fat metabolism 1.
These supplements contain several ingredients, each with their own specific mechanism of action, and when combined, are suggested to elicit a cumulative effect on overall fat and weight loss.
In general, most of these ingredients work by stimulating lipolysis (fat breakdown) or inhibiting lipogenesis (accumulation of fat) 2.
Some of the most popular ingredients include caffeine, carnitine, green tea, conjugated linoleic acid (CLA), forskolin, and chromium.
By increasing the metabolic rate and enhancing the central nervous system's activity, fat burners trigger the release of catecholamines like adrenaline and norepinephrine, which subsequently trigger the release of glucose from the liver and stimulate lipolysis (the breakdown of adipose tissue).
The mobilization of stored fatty acids helps increase energy (ATP) production by using fat as an energy substrate. The more fat that is released for energy, the greater the fat loss.
But many of the ingredients in fat burners also help improve endurance, alertness, memory, physical performance, and reduce fatigue onset. Basically, they enable you to train longer and harder.
Looking at it logically, it makes sense and seems effective. But if you take a deeper look into some of the effects of these ingredients, you'll see that yes, they may offer a benefit to performance and body composition, but they also elicit some undesired effects on both short-term and long-term health.
Some cause heart palpitations and high blood pressure, while others cause jitters, nervousness, irritability, and liver damage.
With respect to long-term outcomes, few ingredients directly affect liver health, but there are plenty of adverse side effects to go around that affect you body-wide.
Let's take a look at some common ingredients and their effects on your liver.
Common Fat Burner Ingredients That May Damage The Liver
One problem encountered by fat burners is that people commonly associate natural with safe. Manufacturers like to claim that because their product ingredients are predominantly of natural origin, they are entirely non-toxic.
But natural and non-toxic are not synonymous. Some 'natural' ingredients used in fat burners can cause issues when taken in excess or improperly.
Derived from the bark of the African evergreen tree Pausinystalia Yohimbe, yohimbine elicits potent hyperadrenergic effects because it acts as an alpha-2 receptor antagonist.
In moderate doses, there have been no side effects of safety issues noted. However, in excess—primarily doses larger than 20mg—yohimbine has been noted to cause agitation, anxiety, hypertension, and tachycardia 3.
One study has noted that yohimbine ingestion can exacerbate lipopolysaccharide-induced liver injury in mice 4, but this effect is not conclusive in humans.
Most of us know caffeine as a potent adenosine receptor antagonist that stimulates the central nervous system to increase alertness and energy. For a lot of us, it's a daily lifeline to keep us functioning.
In terms of fat loss, caffeine is effective. It inhibits enzymes that breakdown cAMP to increase accumulation and stimulate HSL-driven lipolysis (fat breakdown). It also inhibits lipogenesis, or the formation of new fat cells, to help prevent storage.
In general, caffeine has a pretty good safety profile 2. The CNS stimulatory effects are elicited at around 3mg per kg of body weight, and doses of <400mg daily appear to be well-tolerated with little side effects.
Acute clinical toxic effects start around 1000mg, while exceeding this level (> 2000 mg) reaches more severe toxic effects manifesting as nausea, vomiting, tachycardia, seizures, and cerebral edema, and can also lead to electrolyte disorders 2.
Caffeine doesn't appear to harm the liver when consumed in moderate amounts. However, one study noted that chronic caffeine administration might intensify acute experimental hepatitis, possibly through its antagonism of adenosine 2A receptors 4.
But also keep in mind that if you're sensitive to caffeine, these effects can arise from much lower doses, even those considered safe and tolerable for most people.
Green Tea Extract
Green tea extract is a common ingredient in many natural fat loss supplements. The active components of green tea that its proposed benefits are attributed to are caffeine and catechins, specifically epigallocatechin gallate (EGCG).
Green tea and its components may reduce body weight by increasing energy expenditure and fat oxidation, reducing lipogenesis, and decreasing fat absorption 5, 6.
It may also reduce glucose absorption by inhibiting relevant GIT enzymes involved in digestion 2.
There are minimal safety risks associated with moderate consumption. Some reports suggest mild constipation, abdominal discomfort, nausea, and increased blood pressure. But it's not small doses we're concerned with.
Because GTE contains more than 50% EGCG, large doses can be toxic to the liver and result in liver damage. Consumption of certain green tea extracts—primarily ethanolic extracts of green tea—has been linked to liver damage in at least 50 case reports since 2006 7, 8.
Green Coffee Bean
Compared to roasted coffee beans, green coffee beans contain higher levels of chlorogenic acid, which is shown to inhibit fat accumulation, regulate adipogenesis, and modulate glucose metabolism, potentially by reducing glucose absorption in the gut 9.
It does this by affecting lipid metabolism through activating AMPK, which results in the suppression of fatty acid synthesis; AMPK regulates cellular metabolism and is a key mediator in converting adipocytes from anabolizing to catabolizing lipids 2.
Generally speaking, green coffee bean elicits few side effects in doses up to 200mg daily, but some people may experience headaches and UTIs from chronic consumption. As it does contain caffeine, some people may experience adverse effects if they're sensitive to caffeine.
Garcinia Cambogia (Hydroxycitric Acid)
Extracts of Garcinia cambogia are a common ingredient in a lot of weight-loss supplements due to the presence of hydroxycitric acid (HCA). HCA inhibits the ATP-citrate lyase enzyme, which results in decreased concentrations of malonyl-CoA 2.
Malonyl-CoA serves as both a substrate for lipogenesis and as an inhibitor of the CPT-I enzyme. Both actions diminish fatty acid synthesis and increase fat oxidation.
Studies show that garcinia cambogia is relatively safe for consumption, but some adverse side effects have been reported; they are generally mild and include headache, nausea, upper respiratory tract symptoms, and gastrointestinal symptoms.
However, several cases of liver toxicity have also been reported in higher doses 10, 11.
Safer Alternatives For Liver Health
If you're looking for all the benefits of a conventional fat burner without all the drawbacks, we've got something for you.
Burn Lab Pro delivers all the fat loss and performance-enhancing benefits, with none of the risks of most fat burners you'll find on the market.
It's a powerful combination of 5 natural—and we mean actually natural (and safe)—ingredients designed to rev your metabolism, melt fat away, enhance athletic performance, and accelerate recovery.
ForsLean helps breakdown and burn stubborn fat, preserve muscle, and enhance muscle growth. HMB (B-hydroxy-B-methylbutyrate) supports muscle preservation, muscle growth, and muscle recovery to enhance weight loss and lean mass development.
Capsimax cayenne pepper extract provides stimulant-like fat loss benefits without the negative side effects. GTF-Chromium supports fat loss and weight loss by regulating insulin activity and fighting insulin resistance. And BioPerine black pepper extract stimulates thermogenesis to speed up calorie burn and block the formation of new fat cells.
It's the cleanest, safest, and most effective vegan fat burner on the market. Why wouldn't you want to try it?
Final Thoughts: Are Fat Burners Bad For Your Liver?
There are many nutritional supplements on the market that make use of the word 'natural' to sell their products.
And while most people see the word natural and assume it's totally safe because the ingredients originate from natural compounds, it's not exactly true.
Many ingredients of natural origin can elicit some pretty hefty side effects and toxicity when taken in excessive doses or for long periods. Some common fat burners ingredients have been found to be particularly harmful for the liver.
But with Burn Lab Pro, you don't have to worry about acute toxicity or long-term side effects.
BLP is designed with your health in mind and contains none of the conventional fat-burning ingredients that can lead to long-term health effects. Just pure, clean ingredients that help you maximize fat loss.
- AE Jeukendrup, R Randell. Fat burners: nutrition supplements that increase fat metabolism. Obes Rev. 2011;12(10):841-851.
- Ž Jakopin. Risks associated with fat burners: A toxicological perspective. Food Chem Toxicol. 2019;123:205-224.
- N Cimolai, T Cimolai. Yohimbine use for physical enhancement and its potential toxicity. J Diet Suppl. 2011;8(4):346-354.
- IR Miousse, CM Skinner, H Lin, et al. Safety assessment of the dietary supplement OxyELITE™ Pro (New Formula) in inbred and outbred mouse strains. Food Chem Toxicol. 2017;109(Pt 1):194-209.
- R Hursel, MS Westerterp-Plantenga. Catechin- and caffeine-rich teas for control of body weight in humans. Am J Clin Nutr. 2013;98(6 Suppl):1682S-1693S.
- TM Rains, S Agarwal, KC Maki. Antiobesity effects of green tea catechins: a mechanistic review. J Nutr Biochem. 2011;22(1):1-7.
- American Herbal Products Association. Botanical Safety Handbook. 2nd ed. Boca Raton, Florida: CRC Press; 2013.
- VJ Navarro, I Khan, E Björnsson, LB Seeff, J Serrano, JH Hoofnagle. Liver injury from herbal and dietary supplements. Hepatology. 2017;65(1):363-373.
- I Onakpoya, R Terry, E Ernst. The use of green coffee extract as a weight loss supplement: a systematic review and meta-analysis of randomised clinical trials. Gastroenterol Res Pract. 2011;2011:382852.
- KE Lunsford, AS Bodzin, DC Reino, HL Wang, RW Busuttil. Dangerous dietary supplements: Garcinia cambogia-associated hepatic failure requiring transplantation. World J Gastroenterol. 2016;22(45):10071-10076.
- R Corey, KT Werner, A Singer, et al. Acute liver failure associated with Garcinia cambogia use. Ann Hepatol. 2016;15(1):123-126.