Supplement analysis backed by scientific evidence · PT

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Limited evidenceWeight management

Forskolin (Coleus)

Forskolin's fat-burner reputation rests on two small 12-week trials from 2005 - and neither actually produced weight loss. One showed a body-composition shift in men without weight change; the other found nothing in women. It is not a proven weight-loss supplement.

What the science says

  • Changed body composition in men without causing weight loss Limited evidence

    Thirty overweight and obese men took 250 mg of a 10% forskolin extract twice daily or placebo for 12 weeks. Body fat percentage and DXA fat mass fell significantly versus placebo, bone mass changed, free testosterone rose, and lean body mass showed only a trend (p = 0.097). With 15 men per group and no significant weight loss, this is a hypothesis-generating result, not proof of a fat-loss effect.

  • No effect in women Limited evidence

    Twenty-three mildly overweight women took the same product and dose for 12 weeks. There were no significant differences in fat mass, fat-free mass or body fat percentage; Coleus only tended to blunt weight gain (-0.7 vs +1.0 kg, p = 0.10). The authors concluded it does not promote weight loss, and no clinically significant changes appeared in blood lipids, liver and muscle enzymes, thyroid hormones, heart rate or blood pressure.

  • Testosterone booster Limited evidence

    The free-testosterone increase seen in a single 15-man trial has never been replicated, and no trial has linked forskolin to strength, performance or lean-mass gains in trained people.

  • Other uses (eye pressure, bronchodilation) Limited evidence

    Forskolin raises intracellular cAMP and has been investigated as an eye drop for intraocular pressure and by inhalation for bronchodilation. Those are entirely different routes and formulations and tell you nothing about oral capsules for fat loss.

Dosage & safety

Studied dose250 mg of a 10% Coleus forskohlii extract (about 25 mg forskolin) twice daily - the exact dose used in both 2005 trials. No evidence supports higher doses.
SafetyReported effects include loose stools and increased bowel movements. Forskolin is a vasodilator that increases cardiac cAMP signaling, so it can lower blood pressure and increase heart rate; avoid combining with antihypertensives and nitrates without medical supervision. It may increase bleeding risk with anticoagulants and antiplatelet drugs - stop at least two weeks before surgery. It increases gastric acid secretion, so avoid with active peptic ulcer, and it is contraindicated in polycystic kidney disease. Avoid in pregnancy and breastfeeding.

Scientific references

Where to buy

Nature's Craft, Forskolin, 60 Capsules (250 mg per Capsule)

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