Coleus forskohlii

What is Coleus forskohlii?

Coleus forskohlii is a plant in the mint family that grows in subtropical regions such as India and Thailand. Its root contains forskolin, a compound that activates an enzyme called adenylate cyclase and raises levels of the signaling molecule cAMP in cells. In theory that could increase the breakdown of stored fat, which is why forskolin became a popular weight-loss ingredient.

What the research says

The NIH Office of Dietary Supplements summarizes the evidence as a few short-term clinical trials showing no effect on body weight, with no safety concerns reported at typical doses of 500 mg per day for 12 weeks. A systematic review published in 2026 identified four randomized controlled trials and concluded that the extract may reduce fat mass and body fat percentage, but that findings for weight loss and overall body composition were inconsistent. The authors called for high-quality, longer trials before firm conclusions can be drawn.

There is no meaningful human evidence that Coleus forskohlii supports blood sugar. Its presence in glucose formulas is tied to fat-burning marketing rather than glucose research.

How it’s used in supplements

Trials have typically used 250 mg of an extract standardized to 10% forskolin, taken twice daily. Many multi-ingredient products do not state the forskolin content or the amount of extract, so it is impossible to tell whether they come close to studied doses.

Reported side effects in trials were generally mild, with more frequent bowel movements and loose stools the most common, according to the Office of Dietary Supplements. Because forskolin acts on cell signaling pathways that also affect blood vessels and the heart, people taking blood pressure medicines, blood thinners or heart medicines, and those who are pregnant or breastfeeding, should talk with a doctor before using it.

For people focused on blood sugar, Coleus forskohlii adds little. Its research targets body composition, its effects there are inconsistent, and there is no evidence it changes glucose or insulin in people. If you are trying to improve both weight and blood sugar, the combination with the best evidence remains gradual weight loss through diet and regular physical activity, supported by your health care team. A supplement that leans on forskolin for “fat burning” claims should be judged with that in mind. Also note that some labels list the plant under its newer botanical name, Plectranthus barbatus, so the same ingredient can appear under different names. Checking for a stated forskolin percentage and an extract amount is the only way to compare a product with the trials.