Diet & Fitness

Coleus for Weight Control

Also indexed as: Coleus forskohlii, Forskolin

Coleus

Parts Used & Where Grown

This attractive, perennial member of the mint (Lamiaceae) family originated in the lower elevations of India. It is now grown around the world as an ornamental plant. The root is used medicinally.

How It Works

Forskolin, a chemical found in coleus, activates the enzyme adenylate cyclase.¹ This enzyme is a turnkey compound that initiates a cascade of critical events within every cell of the body. Adenylate cyclase and the chemicals it activates comprise a “second messenger” system that is responsible for carrying out the complex and powerful effects of hormones in the body. Stimulation of the second messenger system by forskolin leads to blood vessel dilation,² inhibition of allergic reactions,³ and an increase in thyroid hormone secretion.⁴ Forskolin has other properties as well, including inhibition of the pro-inflammatory substance known as platelet-activating factor (PAF)⁵ and inhibition of the spread of cancer cells.⁶

Studies in healthy humans, including at least one double-blind trial, have shown that direct application of an ophthalmic preparation of forskolin to the eyes lowers eye pressure,⁷^,8 thus reducing the risk of glaucoma. Direct application of the whole herb to the eyes has not been studied and is not recommended.

Forskolin may help dilate blood vessels and improve the forcefulness with which the heart pumps blood. A preliminary trial found that forskolin reduced blood pressure and improved heart function in people with cardiomyopathy.⁹ It is unknown if oral coleus extracts would have the same effect. A small double-blind trial found that inhaled forskolin could decrease lung spasms in asthmatics.¹⁰ It is unclear if oral ingestion of coleus extracts will provide similar benefits.

Why Do Dieters Use It?*

Some dieters say that coleus enhances one’s ability to perform aerobic exercise.

What Do the Advocates Say?*

Although there have been reports of increased thyroid secretion from supplementation with coleus, these may or may not support weight loss.

How Much Is Usually Taken by Dieters?

Although no clinical trials have been done, there are modern references to use of the herb coleus for weight loss.¹¹ 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.

Nutritional Supplement