Thermogenics are dietary supplements that boost the body’s basal metabolic rate (BMR), also known as the resting metabolic rate. There any many different thermogenic substances that work in different ways to achieve an increase in metabolism. The quantity of a thermogenic taken increases the potential for negative side effects experienced by the user.
Gastrointestinal side effects are generally caused by stimulant-based thermogenics like caffeine. Cramping, nausea, diarrhea, bloating, flatulence and abdomen distention can all be caused by thermogenics. Building a tolerance to these substances by slowly increasing the amounts taken can eliminate or lessen the severity of these symptoms.
Thermogenics can cause headaches, either while taking them or after you’ve stopped taking them (due to caffeine withdrawal). Flushed cheeks and facial sweating are also common with thermogenics. A more serious side effect is the possibility of stroke.
Cardiovascular side effects specific to thermogenics include heart palpitations, fluttering, irregular heart beat, high blood pressure, and more seriously, heart attack. The thermogenic Ephedra was pulled from the consumer market by the U.S. government due to several Ephedra-related fatalities, of which seven were heart attacks. However, some of these deaths were due to overdoses of the thermogenic.
Thermogenics can impair immune system function. Disrupting sleep patterns or causing insomnia, both of which impair immune function, is one way. Lack of sleep can also elevate cortisol levels, which further stress the adrenal and immune systems.
Another way thermogenics can affect the immune system is by stressing the adrenal glands, which affect the functioning and circulation of immune system cells.
Thermogenics can affect the mood and mental health of the user as well. Manic feelings of euphoria are sometimes reported with stronger thermogenic compounds, and many companies list this as an attribute of the products. However, there is generally a “down” period after the manic feeling dissipates.
Irritability is common in users, especially with caffeine-heavy thermogenics. Mood swings and feelings of withdrawal often occur when a user stops taking a thermogenic compound.
These effects may be especially intense for people who suffer from depression, anxiety or bipolar disorder.