Forskolin

non-nutrient/non-botanical

What is it

Forskolin is a labdane diterpene compound extracted from the roots of Coleus forskohlii (also known as Plectranthus barbatus), a plant used in traditional Ayurvedic medicine. It is widely studied in cell biology for its ability to directly activate adenylyl cyclase and is marketed in supplements for weight loss, body composition, and cardiovascular support.

How it works

Forskolin's defining mechanism is direct activation of the enzyme adenylyl cyclase, which raises intracellular cyclic AMP (cAMP). Higher cAMP levels propagate signals from many hormones, including those involved in lipolysis (breakdown of stored fat), thyroid hormone release, and smooth muscle relaxation. This makes forskolin a popular tool in laboratory research. In humans, oral forskolin is poorly absorbed, which limits how much of the laboratory activity translates to clinical effects. Clinical trials of forskolin extracts in obesity and other conditions have shown small and inconsistent effects. Some studies suggest modest changes in body composition without significant weight loss. Cardiovascular effects (lower blood pressure, increased heart contractility) have been observed in IV administration studies, but oral supplements rarely produce dramatic effects.

Evidence for 4 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Asthma (theoretical)

Grade C

Moderate evidence

Some older studies, using inhaled or IV forskolin, have shown bronchodilator effects. Oral supplements do not reliably reproduce these effects.

Glaucoma (eye drops, not oral)

Grade C

Moderate evidence

Topical forskolin eye drops have been studied for lowering intraocular pressure with some positive results. This does not apply to oral supplements.

Body composition / weight management

Grade D

Mixed evidence

Small randomized trials of Coleus forskohlii extract in overweight adults have shown small effects on body fat percentage and lean mass, but most trials have not demonstrated significant weight loss compared with placebo. Effects are modest at best.

Blood pressure / cardiovascular function

Grade D

Mixed evidence

IV forskolin lowers blood pressure and improves cardiac output in studies, but oral supplements show limited and inconsistent effects on blood pressure due to poor absorption.

3 commercial forms

Coleus forskohlii extract (standardized to 10% forskolin)

Oral bioavailability is low

The most commonly studied supplement form. Comes from the root of the plant.

High-percent forskolin extracts (20-40%)

Same low oral bioavailability

Higher concentration extracts, allowing smaller capsules. No clinical evidence that higher standardization yields better outcomes.

Coleus forskohlii root powder

Variable forskolin content

Used in traditional Ayurvedic preparations; less standardized.

Dosage

Most studies have used 250 mg of Coleus forskohlii extract standardized to 10% forskolin (about 25 mg forskolin) twice daily. Some products provide 40-50% standardized extracts at lower volumes. Optimal dosing for weight or cardiovascular outcomes has not been established.

When and how to take it

Most studies have used twice-daily dosing with meals to improve absorption and tolerability. Because of potential blood-pressure effects, monitor for lightheadedness if combined with other antihypertensive agents. Avoid taking near bedtime if heart rate increases are noticed.

Safety

Generally well tolerated at supplement doses. Reported side effects include low blood pressure, increased heart rate, headache, and gastrointestinal upset. Because forskolin can increase stomach acid secretion, it may worsen symptoms in people with ulcers or GERD. Long-term safety in humans is not well characterized.

Who should be cautious

Avoid in pregnancy and breastfeeding due to insufficient safety data. People with low blood pressure, bleeding disorders, gastric ulcers, polycystic kidney disease, or those taking anticoagulants or antihypertensive medications should consult a clinician before use. Discontinue at least two weeks before scheduled surgery.

Interactions

Forskolin can interact with blood pressure medications (beta blockers, calcium channel blockers, antihypertensives), blood thinners (warfarin, aspirin), and antiplatelet drugs by potentially increasing bleeding risk and amplifying blood-pressure-lowering effects. It may also interact with nitrates, anti-arrhythmics, and asthma medications.

Frequently asked questions

Does forskolin really help with weight loss?⌄

Clinical evidence is weak. Some studies show small changes in body composition, but most do not show meaningful weight loss versus placebo.

Is forskolin the same as Coleus?⌄

Forskolin is the active compound. 'Coleus' usually refers to Coleus forskohlii (Plectranthus barbatus), the plant it comes from. Supplements may list either name.

Can forskolin lower my blood pressure too much?⌄

Forskolin has blood-pressure-lowering activity. People on antihypertensive medications or with low baseline blood pressure should monitor for lightheadedness or dizziness.

Why are laboratory effects so much stronger than supplement effects?⌄

Most laboratory studies of forskolin use direct application to cells or IV administration. Oral forskolin is poorly absorbed, so much of the in-vitro potency does not translate.

Is forskolin safe long-term?⌄

Most supplement studies have been short (8-12 weeks). Long-term safety is not well established. Monitor for cardiovascular and gastrointestinal effects with prolonged use.

References

  • Forskolin (Wikidata) — Wikidata link
  • Forskolin (PubChem CID 47936) — PubChem link
  • Forskolin (ChEBI 42471) — ChEBI link

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Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you're pregnant, breastfeeding, on medications, or managing a chronic condition.