The short answer is that some fat burners do have side effects. And sometimes they can be dangerous. That’s why it’s so important to research any supplement you take, and make sure you’re only reading trusted sources. That’s why we spend so much time researching every product we review, whether it’s for thermogenics or appetite suppressants, to make sure that we only recommend safe products to our readers.
Many supplements have side effects that can sneak up on you. The website for the product says there are no side effects, but days after taking a new fat burner you may notice some things about yourself that you don’t think were there before.
In general, we only review and recommend fat burners have no or limited side effects. For instance, on our best fat burners list, the top reviewed supplements have no side effects.
When we write up a product, we’re careful to include any and all indications that you might encounter. Some of the most common (and very mild) side effects we encounter are headaches or restlessness from caffeine products.
The only other side effect to look out for is if you're a woman looking into products containing caffeine anhydrous. It appears on our list of best fat burners for men, but because it can have reactions in some women, we curated a separate list that doesn’t include it all, in our best fat burners for women review.