Forskolin dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
Forskolin did not help mice live longer, in either sex, in the 2021 test where epicatechin, halofuginone and mitoglitazone all made male mice live longer. The human evidence is two 12-week studies with 53 people in total. One found fat loss in men. The other found none in women.
Evidence grade for Forskolin: Limited. The rule: people have taken it in a published study, but fewer than 100 of them. The sum on this page: 2 completed trials, 53 people given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 53
- Human studies
- 2
- Found nothing
- 1
Dose
No human dose established
Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose.
2 completed trials, 53 people given it
5 effects reported, 3 unwanted, 2 wanted, by people using it, not a trial
Goal pages: Fat loss and metabolism, Muscle and strength, Ageing and longevity, Hormones and growth hormone, Heart and circulation
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
Forskolin comes from the root of a plant called Coleus forskohlii. It is sold as a fat burner. In the lab it is a standard tool for switching on a messenger inside cells.
What people take it for
- Fat loss.
- Raising testosterone.
- Living longer.
What studies in people showed
Two small studies from 2005 tested a 10 percent extract for 12 weeks. In 30 overweight men, body fat fell and free testosterone rose. In 23 mildly overweight women, fat did not change. Only 7 women took the real extract. Nobody has run a bigger study since. Now the mice. A US program fed it to mice, and they did not live longer. Three other compounds in the same test did work.
What people report
Reports, not study results
The good
- Overweight men lost some body fat in one small study.
- Women taking it said they felt less hungry.
The bad
- Women saw no change in body fat in the second study.
- The testosterone rise comes from 15 men, and nobody has repeated it.
- Very little of the extract is absorbed when you swallow it.
- We have not collected user reports on this one yet.
Where these come from: The two studies on this page. We have no forum reports on this one.
My bottom line
One of the most hyped fat burners, tested in 53 people back in 2005, with mixed results. Save your money for food and training.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals Forskolin has been tested for in people, biggest studies first. We count only what the studies on this page say, so the real numbers may be higher.
- Losing fat specifically53 people · 2 studies · 1 found nothing
- Keeping or building muscle53 people · 2 studies · 1 found nothing
- Testosterone and male hormones30 people · 1 study
- Losing weight23 people · 1 study · 1 found nothing
- Feeling less hungry23 people · 1 study · 1 found nothing
- Thyroid23 people · 1 study · 1 found nothing
- Blood pressure23 people · 1 study · 1 found nothing
Animal and lab work, not yet tested in people
Real results, but from animals or cells, not people. What works in a mouse often does not work the same way in a person. Nobody can patent this, so nobody would ever earn back the cost of a study in people. That is usually why there is none. The record on this one is set out below.
- Living longer1 animal or lab study
28 of the 36 indexed goals have no study of any kind behind Forskolin
No study in people, animals or cells on this page reports a result for these. That does not prove Forskolin does nothing for them. It does mean anything you have heard about Forskolin and one of these did not come from a study cited here.
Show full evidence
What is Forskolin?
Forskolin did not help mice live longer, in either sex, in the 2021 test where epicatechin, halofuginone and mitoglitazone all made male mice live longer. The human evidence is two 12-week studies with 53 people in total. One found fat loss in men. The other found none in women.
Forskolin comes from the root of a plant called Coleus forskohlii. It is a truly important lab tool. It switches on an enzyme called adenylyl cyclase directly, skipping the usual receptors on the cell surface. That makes it the standard way to raise a messenger called cyclic AMP inside a cell. That reliability is a big part of why it was worth testing. It is also a big part of why it is oversold.
The Interventions Testing Program tested it in mice born in 2021, fed from 7 months of age. Five other compounds ran alongside: 2BAct, dichloroacetate, epicatechin, halofuginone and mitoglitazone. Three of those six worked in males. Epicatechin made them live about 5 percent longer, and halofuginone and mitoglitazone about 9 percent each. Epicatechin and halofuginone also helped more males reach old age. Forskolin was not among them. The report notes that, once again, the wins were mostly in males.
The human record is two small studies of a 10 percent standard extract. In 30 overweight and obese men over 12 weeks, forskolin clearly lowered body fat percentage and fat mass on a body scan compared with a dummy pill. It also raised bone mass and free testosterone. In 23 mildly overweight women on the same plan, the same product did not cause weight loss. There were weak signs it held back weight gain, but no clear differences in fat, lean tissue or body fat percentage. The women taking it said they felt less hungry.
That is one positive study in 15 treated men and one negative study in 7 treated women. It is the honest summary of the human evidence for one of the most heavily marketed fat-loss supplements.
How does Forskolin work?
It switches on an enzyme called adenylyl cyclase directly, without needing a receptor. That raises cyclic AMP, a messenger inside the cell. Cyclic AMP turns on another enzyme that frees stored fat from fat cells. That is the whole basis of the fat-loss claim. Cyclic AMP also sits upstream of some hormone signals, including thyroid and sex hormones, which is the proposed route to the testosterone result. The problem with a pill is this. Something that raises cyclic AMP in every cell it reaches does not pick out fat cells. And so little of the swallowed extract is absorbed that a capsule cannot be assumed to act like a lab dish.
What have studies in people found about Forskolin?
Two 12-week studies from 2005 with 53 people in total, each with a dummy-pill group. One found a benefit in men and one found none in women. Nothing since at any size, and nothing on ageing.
- 30 overweight and obese men, 12 weeks: body fat percentage and fat mass fell clearly on a body scan, and free testosterone rose.
- 23 mildly overweight women, 12 weeks, same product and dose: no clear change in fat, lean tissue or body fat percentage.
- The women's study had only 7 people taking the extract. That is too few to spot anything but a large effect.
- Neither study found meaningful changes in blood fats, liver enzymes, thyroid hormones, heart rate or blood pressure.
- No human study has looked at lifespan or healthy ageing.
What this does not tell you: Fifty-three people, across two studies from about two decades ago, with results that point different ways in men and women. That is not enough for a confident claim about body fat. The testosterone result comes from one group of 15 men in one study, and no one else has repeated it. How it works is not in doubt, since forskolin raises cyclic AMP in any cell it reaches. But nobody has shown in people that a pill gets enough into fat tissue to matter.
The state of the research
When this program finds no lifespan effect, that is a real, costly, careful result. It is also narrower than it sounds. It tested one amount in the food, started at one age, in one kind of mouse, and it counted deaths. A no-effect result tells you that this dose, in these mice, did not change how long they lived. It does not tell you the compound does nothing. It does not tell you a different dose would fail, that the idea behind it is wrong, or that the reason people actually take it has been disproved. Those are separate questions, and most were never asked. This site tries to avoid mistakes in both directions. A mouse lifespan win is not proof a supplement works. A mouse lifespan miss is not proof it does nothing.
Forskolin earns its place on this page because its test run makes the point better than any comment could. Six compounds went into the 2021 mouse run. Three of them made male mice live 5 to 9 percent longer. Forskolin did not. Same three labs, same mice, same way of mixing it into food, same starting age, same maths, same paper.
That is what a well-run no-effect result looks like. It is why this program's misses count for more than a miss from one lab. The test could clearly spot an effect of the size it was looking for, because it did, three times, in the other groups.
What it still does not tell you is whether the thing people buy forskolin for works. That was tested in 53 people in 2005. The answer came back positive in men and negative in women, and nobody has run a bigger study since.
The Interventions Testing Program is paid for by the US National Institute on Aging. It runs each test at three separate labs at the same time, in Bar Harbor, Ann Arbor and San Antonio. It uses a mixed breed of mice, a cross of four strains, so no result can come from one odd strain. It tests males and females. Each group is big enough to spot about a 10 percent change in lifespan. Each compound is mixed into the food from a set age. And the program promises in advance to publish results that show nothing, alongside the ones that work. That promise is why this page can exist. Almost nothing else in ageing research reliably tells you what did not work.
The evidence, in charts
Fig. 1a · how many people
53people, across 2 studies in people cited here
| Study | People | Share |
|---|---|---|
| Obesity Research 2005 | 30 | 57% |
| Journal of the International Society of Sports Nutrition 2005 | 23 | 43% |
One study holds 57% of these people, so the total rests more on one study than its size suggests. Counts are the number of people each study on this page says it signed up. That includes studies that only watched people and gave nobody the compound. Studies still signing people up are left out, and only studies cited on this page are counted.
Fig. 1b · evidence mix
2 of 3 sources here are studies in people. The rest is not.
- Study in people · done in people267%
- Animal study · done in animals133%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
Sources here come from just two years, 2005 and 2026.
Too few different years on this page to draw a timeline.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four countries shown. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 4 · how much does what
Nobody has tested different amounts in people
This chart would show how the effect changes as the amount goes up. For this compound, nobody has measured that in people. So we leave it empty. We will not borrow an animal chart and pretend it works the same in people.
Fig. 5 · what the molecule is
- Kind of compound
- Supplement
- Molecule weight
- 410.5 Da. A labdane diterpene, not a peptide.
- Half-life
- Stated in words, not a numbersee the exact wording below
- Chain length
- None on file
Half-life as stated on file: Not reliably established for the oral extract in humans. No adequate human pharmacokinetic study was located, and oral bioavailability is poor.
No amino acid sequence is on file for Forskolin, which is expected: a supplement is not built from amino acids.
The studies we cite
- Study in people2005Body composition and hormonal adaptations associated with forskolin consumption in overweight and obese men
Body fat fell and testosterone rose, in thirty overweight men. The men all had a body mass index of 26 or above and took 250 mg of a 10 percent forskolin extract twice a day, or a dummy, decided by chance, for 12 weeks. Scans showed body fat percentage and fat mass dropped against the dummy group. Bone mass changed and free testosterone rose. Muscle gain leaned upward but was too small to separate from chance. That is fifteen men per group, and the companion study in women found nothing.
30 men with BMI at or above 26, randomised double-blind to 250 mg of a 10 percent forskolin extract twice daily or placebo for 12 weeks. Body fat percentage and fat mass on DXA fell significantly against placebo, bone mass changed significantly, serum free testosterone rose significantly, and lean body mass showed a non-significant trend upward (p equals 0.097). Fifteen participants per arm.
- Study in people2005Effects of coleus forskohlii supplementation on body composition and hematological profiles in mildly overweight women
The same supplement was tested in women and it did not work. 23 mildly overweight women took a 10 percent Coleus forskohlii extract twice a day or a dummy for 12 weeks, seven on the extract. Fat mass, lean mass and body fat percentage came out the same in both groups. Slight leanings toward less weight gain were too weak to call. Blood fats, liver enzymes, thyroid, insulin, heart rate and blood pressure were unchanged. Seven people is too few to spot anything but a huge effect.
23 women randomised double-blind to 250 mg of a 10 percent Coleus forskohlii extract twice daily (n equals 7) or placebo (n equals 12) for 12 weeks. No significant differences in fat mass, fat-free mass or body fat percentage. Non-significant trends toward mitigating gains in body mass (p equals 0.10) and scanned mass (p equals 0.08). Treated participants reported less hunger and fullness. No clinically significant changes in blood lipids, liver or muscle enzymes, thyroid hormones, insulin, heart rate or blood pressure. The authors concluded it does not appear to promote weight loss but may help mitigate weight gain.
- Animal study2026Extension of lifespan by epicatechin, halofuginone and mitoglitazone in male but not female genetically heterogeneous mice
In mice. Six compounds were mixed into food from 7 months of age. In males, epicatechin made mice live about 5 percent longer, and halofuginone and mitoglitazone about 9 percent each. Forskolin was not one of the ones that worked. The authors note that, as before, the wins were mostly in males.
Interventions Testing Program, mice bred in 2021, all agents fed in the diet from 7 months of age. The cohort tested 2BAct, dichloroacetate, epicatechin, forskolin, halofuginone and mitoglitazone. In males, epicatechin increased median lifespan by about 5 percent and halofuginone and mitoglitazone by about 9 percent each, with epicatechin and halofuginone also increasing 90 percent survival. Forskolin was not among the agents reported to extend lifespan. The authors note the report continues the strong male bias among the programme's positive findings.
Common questions
Has Forskolin been tested in people?
Yes. 53 people given it across 2 completed trials cited here, 1 of which found nothing. Forskolin did not help mice live longer, in either sex, in the 2021 test where epicatechin, halofuginone and mitoglitazone all made male mice live longer. The human evidence is two 12-week studies with 53 people in total. One found fat loss in men. The other found none in women.
What is the Forskolin dosage?
No human dose established. Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose. 2 completed trials, 53 people given it
Is Forskolin FDA-approved?
Sold as a dietary supplement, usually as an extract of Coleus forskohlii root made to a set strength. Not an approved drug and not approved to prevent or treat anything.
Does forskolin burn fat?
It raises cyclic AMP, a messenger that frees stored fat from fat cells. In people, the evidence is two 12-week studies from 2005. 30 overweight men lost a clear amount of body fat compared with a dummy pill. 23 mildly overweight women showed no clear change. Nobody has run a bigger study since.
Does it raise testosterone?
One study in 30 men reported a clear rise in free testosterone over 12 weeks. Total testosterone was not clearly different between the groups. That is fifteen men on the extract, one study, never repeated by anyone else. It is not enough to rely on.
Did it extend lifespan in mice?
No. It was fed from 7 months of age in the National Institute on Aging's 2021 run, and it was not among the compounds that made mice live longer. Three others in the same run, epicatechin, halofuginone and mitoglitazone, made male mice live 5 to 9 percent longer. So the test could clearly spot effects that size.
Why is forskolin so widely used in laboratories?
Because it switches on adenylyl cyclase directly, without a receptor. That makes it the standard way to raise cyclic AMP in a cell for an experiment. That reliability in a dish is often sold as if it meant a reliable effect in a person. It does not. A swallowed extract that is poorly absorbed and reaches every tissue at once is a completely different situation.