What is Coleus forskohlii?
Coleus forskohlii (also called Plectranthus barbatus and Coleus barbatus) is an aromatic perennial plant belonging to the Lamiaceae (mint) family. It is found in tropical and subtropical regions of the world, including the Indian subcontinent, Thailand, Brazil, Ethiopia, and Egypt.[2] Coleus forskohlii has traditionally been used in Ayurvedic medicine for the treatment of cardiovascular, gastrointestinal, respiratory, urinary, and central nervous system disorders.[3][4] Forskolin, the main bioactive compound in Coleus forskohlii, has been investigated as a potential treatment for asthma, glaucoma, and high blood pressure, as well as a fat burner and testosterone booster.[5][6][7][8][9]
What are Coleus forskohlii’s main benefits?
The application of eye drops containing 0.3–1% of forskolin (the main bioactive compound in Coleus forskohlii) may cause small reductions in intraocular pressure, suggesting potential therapeutic effects of forskolin in eye disorders involving ocular hypertension, such as glaucoma.[10][11] Although trials administering forskolin orally in participants with glaucoma have also noted reductions in intraocular pressure, the findings were confounded by simultaneous supplementation with rutin and vitamins B1 and B2.[12][13]
Limited preliminary clinical research suggests that supplementation with Coleus forskohlii extract or forskolin may reduce the number of asthma attacks in children,[5] protect against methacholine-induced airway restriction in healthy adults,[14] increase testosterone levels and bone mineral density (BMD) in men with overweight/obesity,[8] and reduce blood pressure and improve body composition and/or metabolic health in older adults and in adults with overweight/obesity.[7][8][15] However, much more evidence is needed in these research areas before firm conclusions can be drawn.
Findings from some in vitro and animal studies suggest that Coleus forskohlii may have anticancer,[16][17][18] antifibrotic,[19] thyroid-stimulating,[20] and anti-inflammatory[21] properties. However, human trials exploring these potential effects are lacking.
What are Coleus forskohlii’s main drawbacks?
Although supplementation with Coleus forskohlii extract or forskolin is generally considered to be safe and well tolerated at recommended doses, it has been associated with side effects relating mainly to gastrointestinal disturbances (primarily diarrhea).[22][23]
Because supplementation with Coleus forskohlii extract or forskolin has been noted to reduce blood pressure, increase stomach acid levels, and inhibit platelet aggregation, its use may be contraindicated for some individuals.[1]
How does Coleus forskohlii work?
The primary mechanism through which forskolin (the main bioactive compound in Coleus forskohlii) exerts its effects is by activating almost all (8 out of 9) isoforms of the enzyme adenylyl cyclase,[24] which, in turn, increases the production of cyclic adenosine monophosphate (cAMP) within cells.[25] This increase in cAMP levels results in the subsequent modulation of various cellular processes through the activation of protein kinase A (PKA) and other proteins or enzymes, which, in turn, affect a wide range of physiological processes, including metabolism, hormone secretion, muscle contraction, and neurotransmission.[26][27]
What are other names for Coleus forskohlii
- Forskolin (main bioactive compound; previously called coleonol)
- Plectranthus barbatus
- Coleus barbatus
- Makandi
- Patharchur
- 7-Beta-acetoxy-8 13-epoxy-1-alpha 6-Beta 9-alpha-trihydroxy-labd-14-en-11-one
Dosage information
Only a handful of clinical trials have looked at the effects of Coleus forskohlii in humans. Most of these trials have administered 250 mg of Coleus forskohlii extract standardized to contain 10% forskolin twice per day, for a total daily dose of 500 mg of Coleus forskohlii extract, equivalent to 50 mg of forskolin.
Because supplementation with Coleus forskohlii extract or forskolin has been noted to reduce blood pressure, increase stomach acid levels, and inhibit platelet aggregation, it should be used with caution by people with hypotension (low blood pressure) or who are taking antihypertensive (blood-pressure-lowering) drugs, people with blood clotting disorders or who are taking blood thinning medication, and people with stomach ulcers.[1]
Frequently asked questions
Coleus forskohlii (also called Plectranthus barbatus and Coleus barbatus) is an aromatic perennial plant belonging to the Lamiaceae (mint) family. It is found in tropical and subtropical regions of the world, including the Indian subcontinent, Thailand, Brazil, Ethiopia, and Egypt.[2] Coleus forskohlii has traditionally been used in Ayurvedic medicine for the treatment of cardiovascular, gastrointestinal, respiratory, urinary, and central nervous system disorders.[3][4] Forskolin, the main bioactive compound in Coleus forskohlii, has been investigated as a potential treatment for asthma, glaucoma, and high blood pressure, as well as a fat burner and testosterone booster.[5][6][7][8][9]
The application of eye drops containing 0.3–1% of forskolin (the main bioactive compound in Coleus forskohlii) may cause small reductions in intraocular pressure, suggesting potential therapeutic effects of forskolin in eye disorders involving ocular hypertension, such as glaucoma.[10][11] Although trials administering forskolin orally in participants with glaucoma have also noted reductions in intraocular pressure, the findings were confounded by simultaneous supplementation with rutin and vitamins B1 and B2.[12][13]
Limited preliminary clinical research suggests that supplementation with Coleus forskohlii extract or forskolin may reduce the number of asthma attacks in children,[5] protect against methacholine-induced airway restriction in healthy adults,[14] increase testosterone levels and bone mineral density (BMD) in men with overweight/obesity,[8] and reduce blood pressure and improve body composition and/or metabolic health in older adults and in adults with overweight/obesity.[7][8][15] However, much more evidence is needed in these research areas before firm conclusions can be drawn.
Findings from some in vitro and animal studies suggest that Coleus forskohlii may have anticancer,[16][17][18] antifibrotic,[19] thyroid-stimulating,[20] and anti-inflammatory[21] properties. However, human trials exploring these potential effects are lacking.
The handful of available randomized controlled trials exploring the effects of Coleus forskohlii on body weight and body composition have reported mixed results.
One trial found no effect of supplementation with 500 mg of Coleus forskohlii extract (containing 10% forskolin, the main bioactive compound in Coleus forskohlii) daily for a period of 12 weeks on body weight or body composition in women with overweight.[28] On the other hand, a 12-week trial conducted in men with overweight/obesity found that the same supplementation protocol resulted in large reductions in fat mass (−4.5 kg) and body fat percentage (−4%).[8] Finally, the most recent trial examined the effects of the aforementioned supplementation protocol over a period of 12 weeks in adults (24 women; 6 men) with overweight/obesity and found no effects on body weight or body composition.[15]
Whereas the trials above explored the effects of Coleus forskohlii taken orally, one 1987 trial looked at the effects of the topical application of forskolin.[9] In this trial, 4 women who were on a very-low-calorie diet applied a forskolin-containing cream on one of their thighs, with the opposite thigh treated with a placebo cream daily for 4 weeks. At the end of the trial period, there was a 1-cm greater reduction in thigh circumference in the forskolin group than in the placebo group.
Taken together, the findings above suggest either no effects of oral supplementation with Coleus forskohlii on body weight and body composition or gender-specific effects, with potential improvements in men with overweight/obesity but not in women with overweight/obesity. The findings also suggest that the topical application of forskolin may promote regional fat loss. That said, much more research is needed before firm conclusions can be drawn.
There is currently not enough research to say whether Coleus forskohlii affects testosterone.
Specifically, only one trial has looked at the effects of supplementation with Coleus forskohlii on testosterone levels.[8] In this trial, 30 men with overweight/obesity and normal testosterone levels took 500 mg of Coleus forskohlii extract (containing 10% forskolin) daily for a period of 12 weeks. At the end of the trial, the levels of free testosterone increased in the Coleus forskohlii group by 3.5% and decreased in the placebo group by 4.1%, with the difference between groups reaching statistical significance. No effect of supplementation with Coleus forskohlii extract was observed on the levels of total testosterone.
Although supplementation with Coleus forskohlii extract or forskolin is generally considered to be safe and well tolerated at recommended doses, it has been associated with side effects relating mainly to gastrointestinal disturbances (primarily diarrhea).[22][23]
Because supplementation with Coleus forskohlii extract or forskolin has been noted to reduce blood pressure, increase stomach acid levels, and inhibit platelet aggregation, its use may be contraindicated for some individuals.[1]
The primary mechanism through which forskolin (the main bioactive compound in Coleus forskohlii) exerts its effects is by activating almost all (8 out of 9) isoforms of the enzyme adenylyl cyclase,[24] which, in turn, increases the production of cyclic adenosine monophosphate (cAMP) within cells.[25] This increase in cAMP levels results in the subsequent modulation of various cellular processes through the activation of protein kinase A (PKA) and other proteins or enzymes, which, in turn, affect a wide range of physiological processes, including metabolism, hormone secretion, muscle contraction, and neurotransmission.[26][27]
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