Also known as: Coleus forskohlii, Plectranthus barbatus, Forskohlii root extract, Coleonol
Fat MetabolismEmerging evidence
A root extract that became a fat loss staple on the back of one small study and a great deal of television. The mechanism is real; the human results are not what the marketing suggests.
Typical dose
250.0–500.0 mg per day
Split across the day, with food
What it is
Forskolin is a diterpene compound from the root of Coleus forskohlii, a plant in the mint family native to India and used in Ayurvedic practice.
Extracts are standardised to forskolin content, commonly 10 or 20 per cent. That figure matters considerably: 250 mg of a 10 per cent extract supplies 25 mg of forskolin, and comparing products on extract weight alone is meaningless.
Forskolin is genuinely useful as a laboratory tool, used routinely in cell research to raise cAMP. Its reputation as a supplement rests on rather less.
How it works
Forskolin activates adenylate cyclase, the enzyme that produces cyclic AMP. Raised cAMP in fat cells promotes the breakdown of stored fat, which is a genuine and well-characterised pathway.
It is the same broad pathway that adrenaline uses, which is why the mechanism looks so promising for fat loss on paper.
The complication is that cAMP is a universal signalling molecule used by many tissues for many purposes. A compound that raises it everywhere is not selective, and the oral bioavailability question means it is unclear how much reaches fat tissue at supplemental doses.
What the evidence shows
The finding that launched the category came from a small trial in overweight men reporting favourable changes in body composition and testosterone over 12 weeks. It involved around 30 participants.
A parallel trial in women found no effect on body composition, which is rarely mentioned alongside the first.
Subsequent research has not established a reliable fat loss effect, and reviews have generally concluded the evidence is insufficient. Given the mechanism is sound, this is a case where the delivery rather than the biology appears to be the limitation.
Dosing
Typical products supply 250 to 500 mg of a 10 or 20 per cent extract, giving 25 to 100 mg of forskolin. The main trial used 250 mg of a 10 per cent extract twice daily.
Dose against forskolin content rather than extract weight.
Set expectations from the evidence rather than the mechanism. One small positive trial in men and a null result in women is a thin basis for a fat loss purchase, and the diet producing the deficit remains what determines the outcome.
Not well characterised; trial effects assessed over 12 weeks
Timing
Split across the day, with food
Competition status
Permitted — not on the WADA Prohibited List
Category
Fat Metabolism
Safety and side effects
Reported effects are generally mild: digestive upset, loose stools and headache.
Because raising cAMP widens blood vessels and affects heart contractility, forskolin can lower blood pressure and increase heart rate. That matters if either is being managed.
It also increases stomach acid secretion and affects how readily blood clots. Speak to your doctor before use if you take regular medication, and stop before scheduled surgery.
Who should avoid it
Speak to your doctor before use if your blood pressure or heart rhythm is being managed, or if you take anything affecting blood clotting. Take care if you are prone to reflux, since forskolin increases stomach acid. Stop before scheduled surgery. Avoid in pregnancy and breastfeeding.
This entry is provided for information only. Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. Consult a qualified healthcare professional before use if you are pregnant, breastfeeding, taking medication or under medical supervision.
