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Coleus Forskohlii Leaf Extract

Also known as: Plectranthus barbatus, Coleus barbatus, Coleus coerulescens, Forskolin, Indian coleus, Makandi, Pashanabhedi, Coleus forskohlii

Overview

Coleus forskohlii is a medicinal plant traditionally used in Ayurvedic medicine, primarily known for its active compound, forskolin. Forskolin is a diterpene extracted mainly from the roots and leaves of the plant, and it functions by activating adenylate cyclase, which subsequently increases intracellular cyclic AMP (cAMP) levels. This mechanism underpins its proposed uses in weight management, metabolic syndrome support, and for certain cardiovascular and respiratory conditions like asthma. Extracts are commonly standardized to contain 10-30% forskolin. While some randomized controlled trials (RCTs) exist, the overall research maturity is moderate, with a need for more comprehensive systematic reviews and meta-analyses to solidify its efficacy and safety profile. Evidence quality varies, with some well-controlled studies but often limited by small sample sizes and short durations.

Benefits

The primary benefits of Coleus forskohlii, specifically its active compound forskolin, are observed in body composition. Some randomized controlled trials suggest modest reductions in body fat and increases in lean body mass, particularly in overweight and obese adults. For instance, a study using 250 mg of 10% forskolin extract twice daily for 12 weeks reported these changes, though overall weight and BMI changes were not consistently significant. Preliminary evidence also indicates potential improvements in lipid profiles and a reduction in risk factors associated with metabolic syndrome. Secondary effects may include mild blood pressure lowering and bronchodilation, attributed to cAMP elevation, and minor immune modulation. Benefits typically manifest after 8-12 weeks of consistent supplementation. However, the effect sizes are generally small, and clinical significance is not always consistently achieved across all studies, indicating it is not a standalone solution for significant weight loss.

How it works

Forskolin, the active compound in Coleus forskohlii, exerts its effects primarily by directly activating adenylate cyclase, an enzyme crucial for cellular signaling. This activation leads to a significant increase in intracellular levels of cyclic adenosine monophosphate (cAMP). Elevated cAMP then activates protein kinase A (PKA), which is involved in a cascade of physiological processes. These processes include enhanced lipolysis (fat breakdown), vasodilation (widening of blood vessels), and smooth muscle relaxation, particularly in the airways. This mechanism explains forskolin’s proposed roles in fat metabolism, cardiovascular function, and bronchodilation. Forskolin's bioavailability is moderate, and its effectiveness can vary depending on the concentration and solubility of the extract.

Side effects

Coleus forskohlii extract is generally well tolerated in clinical trials when used at studied doses for up to 12 weeks. Common side effects are rare, and no significant adverse events have been consistently reported in controlled studies. Uncommon effects, such as mild increases in heart rate or changes in blood pressure, have been noted but are not consistently observed across all research. Specific contraindications include pregnancy and lactation due to a lack of safety data and its traditional use as an emmenagogue; caution is also advised for individuals with polycystic kidney disease. While drug interactions are not extensively documented, caution is recommended, especially with medications affecting cardiovascular function, given forskolin's potential effects on blood pressure and heart rate. No significant hepatotoxicity or nephrotoxicity has been reported in clinical trials.

Dosage

The typical studied dosage for Coleus forskohlii extract is 250 mg of a 10% forskolin extract, taken twice daily, which provides approximately 25 mg of pure forskolin per day. This regimen has been used in clinical trials for durations ranging from 8 to 12 weeks. The minimum effective dose has not been firmly established, and doses below this level generally lack robust clinical data. There is no established maximum safe dose, as higher dosages have not been extensively studied. For optimal absorption, it is usually recommended to administer the supplement with meals. The quality and standardization of the extract are critical, as the concentration of forskolin can vary significantly between products, directly impacting the effective dosage.

FAQs

Is forskolin effective for weight loss?

Evidence suggests modest and inconsistent effects on body composition, such as slight reductions in body fat and increases in lean mass. It is not considered a standalone solution for significant weight loss.

Is Coleus forskohlii safe for long-term use?

Short-term use (up to 12 weeks) appears safe based on current research. However, long-term safety data are limited, and more studies are needed to confirm its safety beyond this period.

Can it affect blood pressure or heart rate?

Possible mild effects on blood pressure and heart rate have been noted, but these are not consistently significant across all studies. Individuals with cardiovascular conditions should consult a healthcare professional.

Should Coleus forskohlii be combined with other supplements?

There is no strong evidence supporting specific combinations. Caution is advised, especially with other supplements or medications that affect cardiovascular function, due to potential additive effects.

Research Sources

https://pmc.ncbi.nlm.nih.gov/articles/PMC2129145/ – This randomized controlled trial by Godard et al. (2005) investigated the effects of forskolin supplementation in 30 overweight/obese men over 12 weeks. Participants received 250 mg of 10% forskolin extract twice daily. The study found a significant increase in lean body mass and a decrease in fat mass in the forskolin group compared to placebo, with no significant changes in overall weight or BMI. Safety parameters remained normal, but limitations include the small sample size and male-only participant group.
https://pmc.ncbi.nlm.nih.gov/articles/PMC4471649/ – This research from Pharmacognosy Research (2015) focused on characterizing the purity and physical properties of a forskolin extract. The study confirmed a 30% w/w forskolin content and the absence of heavy metals, thereby supporting the quality and suitability of such extracts for clinical applications. This provides foundational data for understanding the composition of standardized Coleus forskohlii extracts.
https://www.drugs.com/npp/forskolin.html – This clinical overview from Drugs.com (2024) synthesizes findings from multiple clinical trials on forskolin. It highlights the inconsistent evidence for weight loss and notes the absence of high-quality meta-analyses. The overview also discusses potential cardiovascular uses and emphasizes safety concerns in specific populations, such as pregnant or lactating women, due to limited data and traditional uses.