Are Fat Burners Actually Dangerous? (Revealed)

Caffeine is the top ingredient in most fat-burning supplements because studies show that it can significantly impact energy expenditure and promote thermogenesis [1]. From what I've observed in my practice, caffeine indeed can do that effectively.

Increased resting metabolic rate (RMR), the number of calories burned while the body is at rest, aids energy expenditure. Caffeine increases RMR by as much as 11%, according to the research published in PubMed [2].

Additionally, studies published in PubMed suggest that caffeine aids fat mobilization from the fat cells. Caffeine is a central nervous system stimulant that directly signals the fat cells to break down fat by increasing adrenaline (epinephrine) [3].

Caffeine is also known to increase blood pressure slightly, or when used in excess amounts, especially for caffeine-sensitive individuals, it might cause dehydration, headaches, stomach upset, or jitteriness [4].

But for healthy individuals, and when used in adequate amounts, it poses no danger whatsoever.

2. Green Tea

Look at many fat burner ingredient labels, and you will likely see green tea extract because it can mobilize fat from the fat cells because of its caffeine and EGCG content. In my clinical experience, green tea extract effectively handles this task.

EGCG is the primary antioxidant found in many teas, particularly green, which can boost the levels of norepinephrine, resulting in increased fat burning [5].

Along with boosting exercise performance, studies published in PubMed support the theory that the extract enhances fat oxidation, particularly during a workout [6].

However, this same beneficial antioxidant can also cause some unwanted effects, especially when consumed in excess. It might contribute to anemia or affect the liver negatively [7].

For these risks and any potential drug interactions, always make sure to consult with your doctor prior to including green tea in your diet.

From patient feedback, fat burners with soluble fiber like glucomannan can be a stimulant-free option to help with weight loss.

Research published by Harvard Health Publishing suggests that consuming 30 grams of fiber daily is enough to promote weight loss [8].

Fiber increases satiety, and this feeling of fullness will likely reduce calorie intake, especially snacking, which will help you maintain a calorie deficit, the key to inhibiting weight gain and promoting weight loss.

“Like other soluble fibers, glucomannan absorbs water in your stomach and contributes to feelings of fullness. In addition, it may promote reduced calorie intake and weight loss in other ways.”

- Atli Arnarson, BSc & PhD

Although generally safe, glucomannan supplements can sometimes present a choking hazard as they absorb a lot of water, so make sure to keep that in mind when consuming them, according to the Journal of Obesity [9].

4. Conjugated Linoleic Acid (CLA)

In my professional experience, CLA, found in some fat burners, has shown potential in enhancing fat metabolism.

Though many animal studies show promise in CLA’s effect on reducing body fat, the results in human studies are less concrete [10].

The CLA found in supplements is a different form than derived from food intake. A 12-week study published in Nutrition showed decreased adipose tissue and increased lean muscle mass with CLA supplementation [11].

CLA is generally considered safe, but it may be responsible for some digestive issues, so keep that in mind as well [12].