Coleus Foskohii
Also known as: Plectranthus barbatus, Coleus, Indian coleus, Makandi, Forskolin, Coleus forskohlii
Overview
Coleus forskohlii is a plant native to India and parts of Asia, traditionally used in Ayurvedic medicine. Its primary bioactive compound, forskolin, is a diterpenoid that directly activates adenylate cyclase, an enzyme crucial for increasing intracellular cyclic AMP (cAMP) levels. This elevation in cAMP is the central mechanism through which forskolin exerts its effects. The supplement is primarily marketed for its potential role in weight management, metabolic health, and cardiovascular support. While research maturity is moderate, with a mix of animal studies and small human trials, the evidence quality is variable. Some well-conducted randomized controlled trials (RCTs) exist, but large-scale meta-analyses are limited. It is available as an herbal supplement or a standardized extract containing forskolin.
Benefits
Research suggests several potential benefits of Coleus forskohlii, primarily attributed to its active compound, forskolin. For body composition, some randomized controlled trials (RCTs) indicate that forskolin supplementation may lead to a reduction in fat mass and an increase in lean body mass, particularly in overweight or obese men. However, these effects are less consistent in women, and the overall impact on weight loss is considered modest. In terms of glucose metabolism, animal studies have shown that forskolin can improve glucose tolerance and insulin sensitivity in high-fat diet-fed mice, along with reducing adipocyte size and improving lipid profiles. While promising, these findings require further validation in human trials. Forskolin may also modulate thermogenesis and energy metabolism, potentially aiding in weight management, but the clinical significance of these thermogenic effects remains unclear. Clinical trials generally report no significant adverse effects, with minor changes in blood markers remaining within normal ranges, suggesting a favorable safety profile for the observed benefits.
How it works
Forskolin, the active compound in Coleus forskohlii, exerts its effects by directly activating adenylate cyclase, an enzyme that catalyzes the conversion of ATP to cyclic AMP (cAMP). This increase in intracellular cAMP levels is central to its mechanism of action, as cAMP is a crucial second messenger involved in numerous cellular processes. Elevated cAMP regulates multiple metabolic pathways, including lipolysis (fat breakdown), insulin secretion, and thermogenesis. Specifically, increased cAMP can inhibit adipocyte differentiation and promote the breakdown of stored fat. Furthermore, enhanced cAMP signaling may improve glucose uptake and insulin sensitivity in liver and muscle tissues. The oral bioavailability of forskolin is moderate, and its absorption can be influenced by the extract's purity and delivery method.
Side effects
Coleus forskohlii supplementation is generally considered safe when used at doses commonly employed in clinical trials, typically up to 250 mg of standardized extract (10% forskolin) twice daily. Serious adverse events have not been reported in these studies. Common side effects are rare and usually mild, with no significant increases in heart rate or blood pressure observed in controlled trials. Minor laboratory changes, such as slight increases in white blood cell counts or calcium levels, have been noted but are typically clinically insignificant and remain within normal ranges. While no major drug interactions or contraindications have been definitively documented in high-quality studies, caution is advised for individuals with pre-existing cardiovascular conditions or those taking blood pressure medications, due to the theoretical potential for forskolin to induce vasodilation. Pregnant or breastfeeding women should also avoid use due to a lack of safety data.
Dosage
Clinical trials commonly utilize a dosage of 250 mg of standardized Coleus forskohlii extract, containing 10% forskolin, administered twice daily. This regimen has been studied for durations up to 12 weeks. The minimum effective dose for most applications is not firmly established, and doses below 250 mg twice daily have limited supporting evidence. While no established maximum safe dose exists, higher doses have not been extensively studied in humans, and caution is advised. The timing of supplementation relative to meals is not standardized, and the impact of absorption factors or co-administration with other supplements has not been well characterized. For optimal results and safety, it is recommended to adhere to the dosages used in clinical research and consult with a healthcare professional.
FAQs
Is forskolin effective for weight loss?
Evidence suggests modest fat loss and lean mass increase, primarily in overweight men. Results are inconsistent across populations, and it's not a robust standalone weight loss solution.
Is Coleus forskohlii safe to take?
Yes, it is generally considered safe with minimal side effects when taken at studied doses (up to 250 mg of 10% forskolin extract twice daily).
How long does it take to see effects from Coleus forskohlii?
Studies typically last 12 weeks, suggesting that consistent supplementation over this period may be required to observe potential benefits.
Does Coleus forskohlii affect blood pressure?
Controlled trials have not observed significant changes in blood pressure. However, caution is advised for individuals with cardiovascular conditions or on blood pressure medications due to theoretical effects.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC8000574/ – This animal study investigated forskolin's effects on high-fat diet-fed mice. It found that forskolin reduced adipocyte size, improved glucose metabolism, and inhibited adipocyte differentiation, suggesting potential benefits for metabolic health.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC2129145/ – This human randomized controlled trial involving 30 overweight/obese men over 12 weeks found that forskolin supplementation increased lean mass and decreased fat mass. The study reported no adverse effects on heart rate or blood pressure, indicating a favorable safety profile in this specific population.
- https://clinicaltrials.gov/study/NCT02143349 – This entry on ClinicalTrials.gov describes a planned or completed human randomized controlled trial involving overweight/obese adults of both sexes. The study aims to measure outcomes such as waist circumference, appetite, and blood lipids, though peer-reviewed results are not yet published.
- https://onlinelibrary.wiley.com/doi/full/10.1002/ptr.5583 – This systematic review highlights forskolin's thermogenic potential but concludes that its clinical weight loss effects are mild and inconsistent. The review points to a limited number of high-quality randomized controlled trials, suggesting the need for more rigorous research to confirm efficacy.