Forskolin is yet another plant extract to make waves in the supplement market, with it being compared to actual anabolic androgrens by at least one company. The potential in the substance is seen by most in its ability to activate adenylyl cyclase, which in turn splits ATP molecules into cyclic AMP and pyrophosphate. cAMP has its fingers in all sorts of metabolic and protein-related processes, and is a hot topic for all sorts of dietary, health, and sport research. Forskolin’s ability to ultimately crank up cAMP is strong enough that it’s a laboratory staple for studying cAMP. Alasbahi and Melzig’s “Forskolin and derivatives as tools for studying the role of cAMP” is a review paper devoted specifically to the topic.

While I first head of forskolin as a pill-based supplement, its earliest successful use as a weight loss treatment came in 1987 when it demonstrated some ability when applied topically as a cream. Since then, forskolin extracts have become a big business for supplement manufacturers. Part of the reason was the release of several studies showing the supplement improving body composition, particularly a twelve-week study by Godard et al. published in Obesity Research 2005. The study was an in vivo look at the compound’s effects on men, and it demonstrated that the substance dropped bodyfat percentages while boosting testosterone production.

There are significant caveats to the most exciting of the body composition studies. One caveat is that most (including Godard) were funded by forskolin-producing supplement companies, and some were confounded by the use of company employees and open-labeling (i.e., the trials weren’t blind.) It’s hard not to be skeptical of a product that demonstrates the most marketable results in trials sponsored by the people who stand to gain the most from this marketability. That said, it’s also important to state here that I don’t think we’re necessarily looking at rigged results in all these cases, especially with Godard, as his later work wasn’t nearly as supportive; it may be the case that he hit on something as an honest outlier due to anything from his sample population to the constitution of the forskolin supplement itself. Other similarly positive studies used questionable means, such as impedance devices for tracking changes in body composition.

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Another caveat is that these successes haven’t been duplicated. Studies looking at women show almost no impact from the supplement, and mixed studies don’t indicate any gender differentiation. What the subsequent studies lacked in body composition results, though, they made up for with interesting evidence of health benefits beyond simple weight loss. Lumping their results together, forskolin seemed to prompt appetite reduction, improve insulin sensitivity, and reduce hypertension. Forskolin’s role in cAMP production, its likely effect on insulin pathways, and a host of other effects could be linked to these results. (A side note is that its impact on insulin in the muscle could hypothetically hamper protein synthesis.)

body composition

One distinct side effect of forskolin is its seeming ability to increase water retention in the bowels, which in turn leads to softer stools, akin to what you might experience if taking a fiber supplement or non-laxative stool softener. Given that no studies feature strict analyses of caloric expenditure and digestive factors, there’s a possibility that this effect plays a role in forskolin’s effectiveness. The increase in bowel bulk could be a factor in reducing food intake by stimulating a full feeling, while simultaneously increasing the rate of food passage in the gut, which could reduce calorie absorption. Since these two mechanisms are thought to be part of why increasing dietary fiber intake can prompt weight loss, it’s reasonable to think there’s a potential for similar impact. One counterpoint to this theory is that the bowel effects may be attributable to an increase in stomach acid production, which wouldn’t carry the same benefits; I don’t think the evidence is as strong here, and lean towards the ‘water retention’ explanation.

Ultimately, any assessment of forskolin is going to be hampered by the limited number of studies conducted: by my count, there are about five that would interest physique enthusiasts and/or people seeking health benefits. And these assessments in turn will be hampered by the lack of congruity among seemingly similar supplements (an inherent feature of the supplement industry) and the expense and expertise required in making sure experimental compounds are what they seller says they are. With this in mind, forskolin is an intriguing supplement because of its potential health benefits, but the possible role of adulterants and contaminants can’t be fully ignored.  I feel safe in partially ignoring them just because the usual “additives” don’t generally help with health issues.

Much less encouraging is forskolin’s ability to impact body composition. Certainly, the health benefits could potentiate or trend into aesthetic changes, though this is a guess. If you’re going to try forskolin supplements, my recommendation is to follow the model exhibited in Godard’s first paper: be an overweight male.

Recommended Reading

  • Godard, M.P., B.A. Johnson, and S.R. Richmond. “Body composition and hormonal adaptations associated with forskolin consumption in overweight and obese males.” Obesity Research, 13(8): 1335-1343, 2005.
  • Godard, M.P. and B.A. Ewing. “Body Composition and Hormonal Adaptations Associated With Forskolin Consumption in Overweight And Obese Women.” Medicine & Science in Sport and Exercise, 41(5) Supplement: S556, May 2009
  • Henderson, Shonteh et al. “Effects of Coleus Forskohlii Supplementation on Body Composition and Hematological Profiles in Mildly Overweight Women.” Journal of the International Society of Sports Nutrition 2.2 (2005): 54–62. PMC. Web. 29 Feb. 2016.
  • Loftus, Hayley L. et al. “Coleus Forskohlii Extract Supplementation in Conjunction with a Hypocaloric Diet Reduces the Risk Factors of Metabolic Syndrome in Overweight and Obese Subjects: A Randomized Controlled Trial.” Nutrients 7.11 (2015): 9508–9522. PMC. Web. 29 Feb. 2016.