According to experts, thermogenic products will work to effectively help you lose weight over a 4 to 6 week period, after which the body develops tolerance and its efficacy decreases. So in fact after a period of a few weeks it will cease to make a difference even if you continue to take the supplements.
In any case, the kind of stimulants that thermogenic supplements have, can be dangerous, particularly ephedra, which is also known as ma huang and ephedrine. This is a banned item, which the FDA has said “present (s) an unreasonable risk of illness or injury, and should not be consumed.”
It is particularly dangerous when combined with other stimulants like caffeine since it can cause side effects such as irregular heartbeat, increased blood pressure and sleeplessness.
Bitter orange or synephrine is also another ingredient in thermogenics but there is not enough evidence to support the claim of weight loss here.
Also thermogenic weight loss is not known to be a healthy or permanent method of weight loss and many users have found that soon after they stopped using the supplement, the weight that was lost all came back.
In conclusion, the thermogenic products may not be the best weight loss supplements around and may end up causing more harm than good.