Thermogenics (a.k.a. “fat-burners”) are some of the most popular supplements amongst experienced bodybuilders, people working towards specific body composition or physique goals, and anyone hoping to put a little pep in their step throughout the day. But before you stock up, it’s important to understand how thermogenics work—and whether or not they’re a good fit for your lifestyle and health needs.
Here’s a quick breakdown of the groups of people who can benefit most from a thermogenic supplement—and who might want to check in with a healthcare provider before loading up.
How Thermogenics Work
“The word ‘thermogenic’ means ‘to produce heat,’” explains The Vitamin Shoppe nutritionist Brittany Michels, M.S., R.D.N, L.D.N., C.P.T. “Metabolically, producing more heat means increasing energy or our metabolism. So, a thermogenic supplement is one that stimulates metabolism.”
Let’s break that down a little more: Your “metabolism” really refers to the energy your body uses for everything from breathing to contracting your muscles during a workout. Whenever your body produces or uses that energy, the chemical reactions involved produce heat as a byproduct, says Brian Tanzer, M.S., The Vitamin Shoppe’s senior manager of scientific and regulatory affairs. This process is called thermogenesis—and we measure how much heat the body creates as a reflection of how much energy (a.k.a. calories) it’s used.
The idea behind thermogenic supplements, then, is that they increase thermogenesis and thus the amount of energy the body uses throughout the day, sums up The Vitamin Shoppe nutritionist Rebekay Blakely, R.D.N.
Typically, thermogenics do this through ingredients that have a stimulating effect on the body (appropriately called “stimulants”), which speed up processes like breathing and heart rate. Stimulants do this by kicking up the production of stress hormones, which can also boost your body’s ability to tap into fat stores for energy, according to the University of Delaware.
Caffeine is one of the most common of these ingredients, Blakely says. However, you’ll also find green tea, green coffee bean extract, guarana, capsaicin, and others in thermogenic supps.
2 Groups Of People That Can Benefit From Thermogenics
While thermogenics understandably have pretty widespread appeal, there are two groups of people, in particular, who stand to benefit most from them.
1. Healthy People with Weight-Loss Goals
Thermogenics are probably the most popular amongst healthy individuals looking for metabolism support. “Those without any medical or health concerns can generally safely use a thermogenic product for short-term metabolic support,” says Michels. “This might be beneficial when looking to jumpstart weight loss or reduce body fat percentage.”
Of course, it’s important to remember that thermogenics are only intended to supplement your lifestyle, so ensuring your nutrition, training, and recovery are on point is key for benefiting from the extra oomph thermogenics may offer.
2. Athletes and Experienced Gym-Goers
The other group that thermogenic supplements can really make a difference for: “athletes looking for an edge in the gym,” Michels says. “Thermogenics can give athletes a little extra boost during workouts.” Remember that whole spiel about ramping up stress hormones and processes like heart rate and breathing rate? That cascade of effects can make for more impressive efforts in the gym—and ultimately greater gains.
Read More: Health Pros Say Discipline Is A Must For Success—Here’s How To Cultivate It
One thing this crew should keep in mind, though, according to Michels: You’ll want to cycle on and off thermogenics to maintain effectiveness. Since caffeine tolerance is no joke, taking scheduled time off from thermogenic supplements helps ensure you feel their impact—and prevents any temptation to take in higher and higher amounts in order to continue feeling a difference as your tolerance builds.
3 Groups Of People Who Should Steer Clear of Thermogenics
Because of the notable physiological effects of thermogenic supplements, they can do more harm than good for certain groups of people.
1. Those Sensitive to Stimulants
If you don’t jive with coffee, pre-workout supplements, energy drinks, and the like, it’s safe to assume you won’t mix well with thermogenics, either. “People who are caffeine-sensitive should avoid thermogenic supplements, as they could trigger symptoms such as anxiety, rapid heartbeat, increased blood pressure, headaches, dizziness, and more,” Blakely says. (Here’s more helpful information on understanding how you metabolize caffeine.)
2. People Who Already Go Hard On Caffeine
On the opposite end of the spectrum are those people who start their day with a jumbo black coffee and chug pre-workout before hitting the gym. Even if caffeine works well for you, you absolutely can get too much of a good thing. “It’s not recommended to exceed 400 milligrams of caffeine daily, from all sources—including supplements, coffee, energy drinks, etc.,” advises Blakely. Take inventory of your current caffeine intake and adjust accordingly if you’re interested in trying a thermogenic.
3. Those With Medical Conditions
The experts all agree: Thermogenics are not a good fit for people with health conditions, especially those with heart-related issues. The reason? Thermogenics can affect heart rate and blood pressure, reminds Blakely. She also recommends that anyone with kidney or liver concerns check in with their physician before using thermogenic supplements.
Read More: All Of The Ways Stress Affects Your Heart Health
Since thermogenics can also have harmful interactions with a variety of medications, Michels advises that anyone taking antidepressants (such as MAOIs or SSRIs), blood thinners, nonsteroidal anti-inflammatory drugs (like ibuprofen and acetaminophen), or pseudoephedrine avoid thermogenics.
Best Practices For Trying Out Thermogenics
If you’re a healthy adult and want to add a thermogenic supplement to your routine, “make sure to buy reputable brands and follow usage recommendations from the manufacturer,” Blakely says. “Do not exceed recommended doses.” A few quality options to look into: OxyShred Thermogenic Fat Burner, Altered Physique Thermogenic Metabolism Igniter, and RAW Burn Thermogenic Powder.