Coleus forskohlii, also known as plectranthus barbatus or Indian Coleus, is a tropical member of the lavender and mint family. It grows wild in the mountains of Nepal, India, and Thailand.
It is used in Ayurvedic medicine as a treatment for heart disease, convulsions, spasmodic pain, and painful urination. However, most modern interest is based on research conducted by Hoechst Pharmacetuicals, a drug company that regularly screens medicinal plants to discover new medications.
Much like certain asthma treatments, forskolin increases cyclic AMP levels, which plays a role in cellular functions and relaxes muscles around bronchial tubes. Its effect on cyclic AMP is also linked to increased fat burn.
Coleus forskohlii supports blood pressure levels by activating adenosine cyclase and cyclic monophaste (cAMP). By activating cAMP, coleus is purported to relax blood vessels and improve circulation, thus reducing blood vessel damage and promoting heart muscle contraction.
In a 1995 animal study, researchers found forskolin exhibited a vaso-relaxing effect on sheep. According to the study, forskolin significantly reduced platelet consumption and improved overall platelet metabolism. Researchers concluded, “forskolin affects blood flow and platelet parameters favorably in the setting of occlusive arterial disease and reconstructive arterial surgery.”
Additionally, coleus forskohlii is being studied for its potential effects on energy production and fat loss. Coleus activates cAMP, which then triggers hormone sensitive lipase (LIPE). When LIPE is activated, it mobilizes energy stores by hydrolyzing triglycerides and freeing fatty acids from adipose tissue (fat stores).
According to research, coleus forskohlii supplementation did not have an effect on weight loss directly. But, scientists surmised coleus “may help mitigate weight gain” when used correctly.
Preliminary studies also suggest coleus forskohlii is a potential asthma treatment. It is believed to stabilize cells that release histamine and inflammatory compounds as well as relaxing smooth muscle tissue.
Coleus forskohlii is generally well tolerated and side effect risk is minimal.
However, coleus does have an impact on blood pressure levels, and individuals with heart problems should consult a doctor before taking coleus.
When combined with blood thinning agents, such as aspirin, ibuprofen, and naproxen, coleus may increase risk of bleeding.
Many natural medicine experts recommend 50 mg coleus extract (18% forskolin), or 250 mg of less-concentrated coleus (1% forskolin) taken 1-3 times daily. Some recommend taking the dried root in 6-12 gram doses, or as a fluid extract in 6-12 milliliter doses daily.
However, the FDA has not issued a daily recommended amount.
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 Shonteh Henderson, Bahrat Magu, Chris Rasmussen,1 Stacey Lancaster, Chad Kerksick, Penny Smith, Charlie Melton, Patty Cowan, Mike Greenwood, Conrad Earnest, Anthony Almada, Pervis Milnor, Terri Magrans, Rodney Bowden, Song Ounpraseuth, Ashli Thomas, and Richard B Kreider. “Effects of Coleus Forskohlii Supplementation on Body Composition and Hematological Profiles in Mildly Overweight Women.” J Int Soc Sports Nutr. 2005; 2(2): 54–62. Published online 2005 December 9. doi: 10.1186/1550-2783-2-2-54.
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 “What medications can interact with coleus?” Natural Standard, the Authority on Integrative Medicine.
 “If I take coleus, how much should I take?” Natural Standard, the Authority on Integrative Medicine.