Coleus is a member of the mint family native to subtropical regions of Africa and Asia, such as India, Thailand, and Uganda. It has a long history of use in traditional medicine, including Ayurveda, where it has been used to support lung, heart, and urinary health, among numerous other uses.1 Its tuberous roots are also commonly made into slightly sour pickles which are served in various relishes in Indian and other continental Asian cuisines.

Like all herbs, coleus contains a multitude of active compounds. However, the tuberous roots of the plant contain its most potent active ingredient, forskolin, which is largely believed to be the most beneficial substance derived from the plant. It has been used extensively in experimental clinical research as a positive control to effectively increase the levels of the important cellular messenger compound cAMP (cyclic adenosine monophosphate).2 Healthcare providers also sometimes give patients forskolin in IV, eye drop, or powder form to treat a range of conditions.

As a supplement taken by mouth it is far newer, and as such, has been subject to less research. I and many others hope that’s about to change!

What Does Forskolin Do?

In the supplement realm, forskolin is predominantly used within formulations to support fat burning and energy levels, but is also applicable for use in products targeting blood pressure, digestion, and testosterone levels.

One of the most rigorous and promising studies concerning supplemental forskolin was conducted by researchers at the University of Kansas a few years ago.3 They found that overweight and obese men lost more than 7.8 times more body fat, added 35 percent more bone mass, and increased their bioavailable free testosterone by almost 34 percent more when they added 250 mg of a 10 percent forskolin-containing coleus to their otherwise unchanged daily lives, twice per day. In other words, 50 mg of total forskolin per day—as compared to subjects who consumed a placebo—realized a significant improvement in both body composition and testosterone levels.

What makes forskolin so effective is its ability to directly and rapidly stimulate almost all known forms of the enzyme adenylyl cyclase, and therefore significantly affect the concentration of the messenger molecule cAMP. This powerful compound activates numerous other enzymes within a range of cells and tissues, and is indirectly involved in far too many cellular functions to list here.

What makes forskolin so unique, though, is that its actions on cAMP levels are reversible, and it accomplishes this action without the use of other cellular receptors such as beta adrenoreceptors, contrary to other well-known fat burners such as ephedrine. Its relative simplicity and dependability are why forskolin is such a commonly used control arm in clinical trials which are looking to assess the role of cAMP for any reason.

What are the performance and physique applications?

Forskolin’s primary draws for physique athletes are its potential as a test booster and fat-burner and the limited studies into the supplement back that up—particularly with men. In a similarly designed study to the Kansas study, researchers out of Baylor found that forskolin reduced weight gain and hunger in obese women, but otherwise didn’t reduce body fat.4

Some evidence, though, suggests that applying forskolin to the skin may provide some site-specific fat loss in overweight and obese women. However, more research is required to better understand if and under which circumstances coleus may help burn fat.