The Ayurvedic botanical offers many health benefits including cardiovascular wellness and enhanced lean muscle mass.
Coleus (Coleus forskohlii) is an herb used in Ayurvedic medicine for promoting healthy cardiovascular, eye, respiratory and digestive function.1 Its active principle is a diterpene known as forskolin.2 Forskolin stimulates and activates the enzyme adenylate cyclase in the heart and smooth muscle. This causes increased production of cyclic AMP (cAMP), which causes calcium channels to open and intracellular calcium concentrations to increase, resulting in increased contractility of heart muscle and relaxation of smooth muscle.3,4,5,6 cAMP is one of the most important regulators of endocrine health, brain chemistry and oxidative metabolism. Researchers speculate forskolin might also activate adenylate cyclase in other cells of the body, such as platelet cells and cells in the thyroid, pancreas, adrenal or pituitary glands.7
While coleus offers many health effects, it is currently best known for its impact on weight management. Forskolin has been shown to promote lipolysis (the breakdown of fat in the fat cells) and weight loss. In one study, six significantly overweight women were given 250 mg Coleus (standardized for 10-percent forskolin), twice daily for eight weeks, while maintaining previous exercise and diet habits.8 Intervention yielded an average weight loss of 9.17 pounds, almost an 8-percent reduction in percentage body fat, and a 4.23-percent increase in percentage of lean muscle—with no side effects. In a longer (12-week) study in mildly overweight women (n=19), providing 250 mg Coleus twice daily had no effect on weight loss; however, subjects taking Coleus experienced less hunger and less fatigue, and were more successful and preventing weight gain.9
The effects are certainly not gender dependent. In a double blind, randomized study, 30 overweight and significantly overweight men were given 250 mg Coleus (10 percent forskolin) twice daily, or a placebo, for 12 weeks.10 The men taking Coleus had a significant decrease in body fat percentage (11.23 percent) and 6-percent increase in lean mass, compared to a 1.73 percent decrease in body fat and less than 3-percent lean mass increase in placebo group. Further, there was a 17-percent increase in total testosterone and a 3.47-percent increase in free testosterone in the Coleus group, with a decrease in both measures in the placebo group. Again, there were no side effects.
In considering the three studies, it appears 250 mg Coleus (standardized for 10 percent forskolin) given twice daily is effective in the treatment of overweight and significantly overweight individuals, but not mildly overweight individuals. The data seems to indicate, therefore, Coleus is indicated for substantial weight loss, not just for five or ten pounds.