Coleus
Coleus forskohlii root is the source of forskolin, a compound that raises intracellular cAMP. Forskolin has real pharmacology when given IV, topically, or by inhalation. Oral Coleus supplements show much smaller, inconsistent effects on body composition, blood pressure, and glucose — typical-dose RCTs are small (n=23–30) and results conflict.
Quick decision guide
May help most
People curious about a body-composition or metabolic adjunct who accept that effect sizes are small and not well replicated.
Common dosing range
250 mg standardized to 10% forskolin (25 mg forskolin), twice daily — the dose used in the body-composition RCTs.
When to expect effects
Weeks (8–12 weeks in trials); acute hemodynamic effects within hours of higher single doses.
Watch out for
Lowers blood pressure and inhibits platelets — risky alongside anticoagulants, antihypertensives, or surgery.
Evidence snapshot
What is it
Coleus, typically referring to Coleus forskohlii (also classified as Plectranthus barbatus), is a perennial plant native to India and East Africa. Its root is used in traditional Ayurvedic medicine, and standardized extracts containing the diterpene forskolin are marketed for weight management, cardiovascular support, and respiratory health.
Is it worth it for you?
Use this as a quick fit check, not a diagnosis.
Worth considering if…
Probably skip if…
Evidence at a glance
| Goal | Effect | Best fit | Time |
|---|---|---|---|
Body fat / composition Limited Evidence | ≈3–4 kg additional fat-mass loss in one male trial; null in female trials; lean-mass preservation possibly more consistent | Overweight adults using it as a 12-week trial alongside diet + training; effect appears stronger in men than women | 8–12 weeks |
Asthma (inhaled forskolin only) Limited Evidence | Bronchodilation similar to fenoterol with inhaled forskolin; null/unclear with oral Coleus | Not relevant to consumer supplement users — this is inhaled pharmaceutical use | Minutes to hours (inhaled only) |
Intraocular pressure / glaucoma (topical only) Limited Evidence | Measurable IOP reduction with 1% topical forskolin; not replicated by oral Coleus | Not relevant to consumer supplement use — only the topical preparation has been tested in humans | Hours (topical only) |
Blood pressure (mild reduction) Mixed Evidence | ≈4 mmHg systolic reduction at 500 mg/d in metabolic-syndrome adults (single small RCT) | Adults with metabolic syndrome / borderline hypertension under monitoring, willing to try an adjunct | 8 weeks in trial |
Glycemic control in metabolic syndrome Mixed Evidence | Small reductions in fasting glucose and HbA1c in a single 8-week pilot (n=36) | Adults with metabolic syndrome under medical supervision exploring adjuncts | 8 weeks |
Body fat / composition
- Effect
- ≈3–4 kg additional fat-mass loss in one male trial; null in female trials; lean-mass preservation possibly more consistent
- Best fit
- Overweight adults using it as a 12-week trial alongside diet + training; effect appears stronger in men than women
- Time
- 8–12 weeks
Asthma (inhaled forskolin only)
- Effect
- Bronchodilation similar to fenoterol with inhaled forskolin; null/unclear with oral Coleus
- Best fit
- Not relevant to consumer supplement users — this is inhaled pharmaceutical use
- Time
- Minutes to hours (inhaled only)
Intraocular pressure / glaucoma (topical only)
- Effect
- Measurable IOP reduction with 1% topical forskolin; not replicated by oral Coleus
- Best fit
- Not relevant to consumer supplement use — only the topical preparation has been tested in humans
- Time
- Hours (topical only)
Blood pressure (mild reduction)
- Effect
- ≈4 mmHg systolic reduction at 500 mg/d in metabolic-syndrome adults (single small RCT)
- Best fit
- Adults with metabolic syndrome / borderline hypertension under monitoring, willing to try an adjunct
- Time
- 8 weeks in trial
Glycemic control in metabolic syndrome
- Effect
- Small reductions in fasting glucose and HbA1c in a single 8-week pilot (n=36)
- Best fit
- Adults with metabolic syndrome under medical supervision exploring adjuncts
- Time
- 8 weeks
Evidence for 5 uses
AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.
Body fat / composition
Supplement benefitTwo 12-week RCTs at 250 mg Coleus extract (10% forskolin) twice daily produced conflicting results. Godard 2005 in 30 overweight men found significant fat-mass reduction (−4.5 kg vs +1 kg placebo), increased lean mass, and a ~33% rise in free testosterone. Henderson 2005 in 23 mildly overweight women found no significant body-composition differences. Loftus 2015 (women, hypocaloric diet) found Coleus preserved fat-free mass better but did not produce greater fat loss. The signal is real but small, possibly sex-dependent, and not replicated in larger trials.
Bottom line: A modest, possibly sex-dependent body-composition adjunct. Don't expect more than what a single small trial showed.
Evidence is mixed
Two 12-week RCTs at the same dose produced opposite results — Godard 2005 (men) showed fat loss; Henderson 2005 and Loftus 2015 (women) showed no fat loss. Sample sizes are small (n=23–30) and no large confirmation trial exists.
Asthma (inhaled forskolin only)
Inhaled forskolin (10 mg) has demonstrated bronchodilation comparable to fenoterol in adult asthmatics, with a 1–2 hour duration. This is a pharmaceutical-grade delivery system, not what supplement users buy. Oral Coleus supplements do NOT reliably reproduce this effect because oral bioavailability is low and forskolin doesn't reach airway smooth muscle at meaningful concentrations.
Bottom line: Don't take oral Coleus for asthma — the route doesn't deliver an effective dose to the lungs.
Intraocular pressure / glaucoma (topical only)
Topical 1% forskolin solution lowers intraocular pressure in healthy volunteers and primates without altering pupil size or aqueous production. This is a research-grade ophthalmic preparation, not an oral supplement. Oral Coleus capsules don't reach intraocular concentrations that would replicate this effect.
Bottom line: Topical forskolin is interesting in ophthalmology research; oral Coleus is not a glaucoma treatment.
Blood pressure (mild reduction)
Supplement benefitForskolin's cAMP-mediated vasodilation produces measurable BP drops when given IV. Oral Coleus is much weaker — Majeed 2020 in 36 metabolic-syndrome patients on 500 mg/d for 8 weeks found a ~4 mmHg systolic reduction. This is the rough size of effect from sodium reduction or moderate weight loss. Useful as adjunct context, not a primary BP intervention. The same cAMP mechanism explains the interaction risk with antihypertensive medications.
Bottom line: Real but small; don't substitute for proven BP treatments.
Glycemic control in metabolic syndrome
Supplement benefitForskolin raises cAMP in pancreatic beta cells, which can amplify insulin secretion. The Majeed 2020 pilot in metabolic-syndrome patients (500 mg/d, 8 weeks) found small reductions in fasting glucose and HbA1c. The effect is plausible mechanistically but the trial is small (n=36), unblinded, and the absolute changes are modest. No larger confirmation exists.
Bottom line: Interesting pilot signal; treat as exploratory only.
How it works
How to take it
What to track
Bottom line: 250 mg of 10% forskolin extract twice daily for 12 weeks is the studied protocol. Stop if you see no clear benefit by week 12, or if you start a new medication that interacts.
5 commercial forms
Compare the main delivery options and what they’re best suited for.
Coleus forskohlii root extract (10% forskolin)
Standard supplement formThe form used in the body-composition RCTs. 250 mg capsule = 25 mg forskolin. Look for verified standardization — independent testing has flagged products with much less forskolin than labeled.
Oral bioavailability is low; effects are smaller than IV or inhaled routes.
Coleus forskohlii root extract (20% forskolin)
Higher concentrationMore concentrated extract — a 125 mg capsule delivers the same 25 mg forskolin as a 250 mg of 10% standard. No evidence of better outcomes per mg forskolin; choose based on price and capsule size.
Same oral bioavailability per mg forskolin.
Whole Coleus forskohlii root powder
Lowest potencyNon-standardized dried root. Forskolin content varies dramatically by batch and source (0.1–0.5% typical). Hard to dose reliably for any specific effect.
Unpredictable forskolin delivery per dose.
Inhaled forskolin (research / pharmacy)
Pharmaceutical routeSolubilized forskolin delivered as an aerosol; tested for bronchodilation. Not a consumer product — historical research use only.
High lung concentration; bronchodilator effect comparable to fenoterol.
Topical forskolin 1% solution (research)
Ophthalmic researchUsed in clinical research for intraocular pressure lowering. Not commercially available as a glaucoma treatment.
Achieves meaningful intraocular concentrations.
Safety
Know the common side effects, key cautions, and who should avoid it.
Common side effects
Serious risks
Forskolin inhibits platelet aggregation via cAMP elevation. Combined with anticoagulants or antiplatelets it can meaningfully increase bleeding risk. Stop at least 2 weeks before any surgery.
Forskolin lowers blood pressure. Stacking with antihypertensives can cause symptomatic hypotension; people with low baseline BP can become lightheaded or faint.
Forskolin increases gastric acid secretion via cAMP. Can worsen reflux, peptic ulcer disease, or interact with PPIs/H2 blockers' intended effect.
Animal studies show uterine and antifertility activity; not adequately studied in human pregnancy. Avoid in pregnancy and when trying to conceive.
Who should avoid it
- People on warfarin, DOACs (apixaban, rivaroxaban), antiplatelets (aspirin, clopidogrel), or with bleeding disorders.
- People with low baseline blood pressure, on antihypertensives, or with hemodynamic instability (e.g. heart failure on optimized medications).
- People with peptic ulcer disease, GERD on PPIs, or other acid-related GI conditions.
- Anyone pregnant, breastfeeding, or trying to conceive — uterine activity in animal studies, no human data.
- Anyone scheduled for surgery within 2 weeks — stop ahead of any procedure due to bleeding risk.
Pregnancy & breastfeeding
Avoid in pregnancy. Forskolin has uterine and antifertility activity in animal studies, and there are no human pregnancy safety data. The supplement isn't worth the unknowns when pregnant or trying to conceive.
Bottom line: More interaction-prone than most herbal supplements. The BP, bleeding, and acid effects mean a careful look at your medication list before starting.
Interactions
Forskolin inhibits platelets via cAMP. Combined with anticoagulants, bleeding risk meaningfully increases. Avoid.
Additive platelet inhibition increases bleeding risk. Avoid.
Forskolin lowers BP. Stacking can cause symptomatic hypotension. Monitor BP closely if you start Coleus while on antihypertensives.
Both lower BP via cAMP/cGMP pathways. Risk of profound hypotension. Avoid.
Both promote cyclic nucleotide accumulation; potential additive BP-lowering. Use with caution.
Forskolin raises gastric acid via cAMP. May partially offset acid suppressors' intended effect.
Choosing a product
What to look for on the label — and what to be skeptical of.
Look for…
Be skeptical of…
Frequently asked questions
Is Coleus the same as forskolin?⌄
Coleus is the plant; forskolin is its main active compound. Most supplements use Coleus forskohlii root extracts standardized to a specified forskolin percentage.
Will Coleus help me lose weight?⌄
Evidence is weak. Small body-composition effects have been reported, but meaningful weight loss versus placebo has not been consistently shown.
Can I take Coleus with blood pressure medication?⌄
It may amplify blood-pressure-lowering effects. Discuss with your clinician before combining.
Is the Coleus in supplements the same as the houseplant?⌄
No. The medicinal species (Coleus forskohlii / Plectranthus barbatus) is different from the ornamental Coleus often kept as a houseplant. Ornamental species are not used medicinally.
How long should I take Coleus to see results?⌄
Most clinical studies have run for 8-12 weeks. If you don't notice changes in this timeframe, additional supplementation is unlikely to help.
References by claim
Body fat / composition
Safety
Memorial Sloan Kettering — About Herbs — Forskolin (Coleus forskohlii) monograph (2024) link
Intraocular pressure / glaucoma (topical only)
Caprioli et al., 1984 — PubMed — Investigative Ophthalmology & Visual Science (1984) link
Asthma (inhaled forskolin only)
Bauer et al., 1993 — PubMed — Klinische Wochenschrift / Eur J Clin Pharmacol (1993) link
Blood pressure (mild reduction)
Majeed et al., 2020 — PubMed — Phytotherapy Research (2020) link
Track Coleus with Pilora
Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.
Coming to App StoreDisclaimer: 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.