Coleus forskohlii is an Ayurvedic medicinal plant used historically to treat high blood pressure, heart failure, eczema, digestive colic, respiratory ailments, painful urination, insomnia, and seizures, as well as overweight and obesity.¹² Laboratory research suggests forskolin, an active compound from coleus, may reduce excessive inflammatory signaling by fat cells.¹³ In a preliminary clinical trial, six overweight women were treated with 250 mg of Coleus forskohlii extract, standardized to contain 10% forskolin, twice daily for eight weeks. On average, the women lost ten pounds of body weight, and body fat was reduced by 8%.¹⁴ In a 12-week placebo-controlled trial that included 23 mildly overweight women, those receiving a standardized coleus extract, at a dose of 250 mg twice daily, lost 0.6 kg (1.3 pounds) of body weight while those receiving placebo gained 1.3 kg (2.9 pounds); although the difference was not statistically significant, it did suggest a possible role for coleus in slowing weight gain.¹⁵ A similar trial that included 30 women with overweight and obesity being treated with a reduced-calorie diet found taking coleus resulted in the same weight loss as placebo; however, coleus had greater positive impacts on insulin levels and insulin resistance, suggesting it may improve metabolic health generally.¹⁶

 

Studies in healthy humans, including at least one double-blind trial, have repeatedly shown that intraocular pressure is lowered by direct application of forskolin, a constituent of the Ayurvedic herb Coleus forskohlii.^17,18 Until ophthalmic preparations of coleus or forskolin are available, people with glaucoma should consult with a skilled healthcare practitioner to obtain a sterile fluid extract for use in the eyes. Direct application of the whole herb to the eyes has not been studied and is not advised.

Coleus forskohlii and its active constituent forskolin have been found to relax blood vessel walls and lower blood pressure in laboratory and animal studies.^19,20 A pilot trial evaluated the effect of two preparations of Coleus forskohlii in subjects with high blood pressure and found 31 of the 41 participants who completed the trial (75.6%) experienced mild blood pressure reductions.²¹ Forskolin was also found to lower blood pressure and increase cardiac output in an uncontrolled preliminary trial with 12 subjects suffering from cardiomyopathy.²²

 

Coleus contains forskolin, a substance that may help dilate blood vessels and improve the forcefulness with which the heart pumps blood.²³ Recent clinical trials indicate that forskolin improves heart function in people with congestive heart failure and cardiomyopathy.^24,25 A preliminary trial found that forskolin reduced blood pressure and improved heart function in people with cardiomyopathy. These trials have used intravenous infusions of isolated forskolin. It is unknown whether oral coleus extracts would have the same effect. While many doctors expert in herbal medicine would recommend 200–600 mg per day of a coleus extract containing 10% forskolin, these amounts are extrapolations and have yet to be confirmed by direct clinical research.

 

Another Ayurvedic herb, coleus, contains forskolin, a substance that may help dilate blood vessels and improve the forcefulness with which the heart pumps blood.²⁶ Recent clinical studies indicate that forskolin improves heart function in people with cardiomyopathy and congestive heart failure.^27,28 A preliminary trial found that forskolin reduced blood pressure and improved heart function in people with cardiomyopathy. These trials used intravenous injections of isolated forskolin. It is unknown whether oral coleus extracts would have the same effect. While many doctors and practitioners of herbal medicine would recommend 200 to 600 mg per day of a coleus extract containing 10% forskolin, these amounts are extrapolations and have yet to be confirmed by direct clinical research.

 

A small double-blind trial found that a constituent of coleus, called forskolin, when inhaled, could decrease lung spasms in asthmatics compared to placebo.²⁹ Coleus extracts standardized to 18% forskolin are available, and 50 to 100 mg can be taken two to three times per day. Fluid extract can be taken in the amount of 2 to 4 ml three times per day. Most trials have used injected forskolin, so it is unclear whether oral ingestion of coleus extracts will provide similar benefits in the amounts recommended above. One study found that 10 mg per day of forskolin taken orally for 2 months was of no benefit for adult asthmatics.³⁰

 

Although clinical trials are lacking, some herbalists use the herb, coleus, in treating people with psoriasis.³¹ Coleus extracts standardized to 18% forskolin are available, and 50 to 100 mg can be taken two to three times per day. Fluid extract can be taken in the amount of 2 to 4 ml three times per day.