You’ve no doubt seen ads for them on social media—and maybe even had a friend or two post about how they helped her slim down quick. Fat-burning teas are everywhere, and their lure of fast, effortless weight loss can be super tempting. But are they legit? Testimonials from slim, toned celebs might make you a believer. (If it worked for her, it’ll work for me!) And since most of the brews claim to be made with all natural, herbal ingredients, it’s easy to assume that at the very least, there’s nothing to lose. (Sculpt your belly, butt, and thighs with the 20-minute workouts in the all-new Prevention Toning Transformation!) But experts disagree. The majority of dietitians and doctors alike say teas that claim to help you burn fat are ineffective at best, and they can be dangerous at worst. Here, three share what they wish everyone new about these products—and why you should steer clear.