What Is It?
Health Benefits

Dosage Information

Guidelines for Use

General Interaction

Possible Side Effects

Evidence Based Rating Scale

What Is It?

In India, practitioners of traditional Ayurvedic medicine have long used the Herb Coleus forskohlii to treat asthma, heart disease, and a range of other ailments. This small herb, which is part of the mint family, is also found in Sri Lanka, Thailand and Nepal.

In the 1970s, researchers isolated a chemically active ingredient in the herb and called it forskolin. The research revealed that some components of forskolin include hypotensive (low blood pressure) and spasmolytic (muscle relaxant) properties. From 1981 to 2008, forskolin was used in more than 18,000 in vitro and in vivo studies due to its effect on a key cell-regulating substance called cAMP (cyclic adenosine monophosphate). In one of these landmark studies, the basic mechanism of action of forskolin was deemed to be the activation and stimulation of an Enzyme (adenylate cyclase) that increases levels of intracellular cAMP. (1) Decreased intracellular cAMP levels can often lead to the development of several adverse medical conditions, such as asthma, angina, hypertension, and some skin conditions like psoriasis, so the stimulation of this compound may be beneficial in preventing and treating these conditions.

Health Benefits

Now available in supplement form, forskolin Extract is commonly recommended for treating hypothyroidism, a condition in which the thyroid gland produces too little thyroid Hormone. However, scientific evidence in that area is lacking. In addition to hypothyroidism, a number of other seemingly unrelated conditions have been linked to low levels of cAMP and may theoretically respond to forskolin treatment. These include, heart disease, high blood pressure, glaucoma, eczema, and psoriasis.

Specifically, forskolin may help to:

  • Treat inflammatory conditions like asthma and eczema. Allergic inflammatory conditions such as asthma and eczema are often characterized by a decrease in cAMP levels in the bronchial smooth muscle and the skin, and by excessive levels of platelet-activating factor (PAF), which helps to regulate smooth muscle contraction and coronary blood flow. By stimulating the release and increasing intracellular levels of cAMP, forskolin aids in the relaxation of bronchial muscles and relief of respiratory symptoms associated with asthma attacks. In addition to stimulating the release of cAMP, forskolin also has been shown to inhibit PAF by interfering with PAF binding to receptor sites. Therefore, forskolin is thought to be useful in treating these allergic conditions. However, scientific evidence in this area has focused on the use of forskolin to treat asthma, while data is lacking in regard to eczema. Some studies have even shown forskolin to be as effective as conventional medication in treating asthma and more effective than conventional medication in preventing asthma attacks. In a 1986 double-blind study, 12 healthy, non-smoking volunteers received either forskolin or the drug fenoterol through metered dose inhalers. Initially (after 3 to 5 minutes), the protective effect of forskolin against inhaled acetylcholine was as good as that produced by fenoterol; however, after 15 and 30 minutes of treatment, fenoterol provided stronger protection. (2) And in a 1993 randomized, double-blind, placebo-controlled study also comparing forskolin to the drug fenoterol, 16 patients with asthma were observed for two hours after using three different preparations: single inhalation doses of fenoterol; 0.4 mg dry powder capsules of fenoterol; or 10 mg forskolin dry powder capsules. All three preparations caused significant improvement in respiratory function and bronchodilation. However, the fenoterol inhalation caused tremors and decreased blood potassium levels, while no such negative effects were seen with forskolin. (3) A 2006 randomized, single-blinded study indicated prophylactic use of forskolin may be beneficial in preventing asthma attacks, and may be more effective than prophylactic use of conventional medicine. In the study, 40 children and adult patients with mild or moderate persistent asthmas were assigned randomly to six months of treatment with 10 mg/day forskolin in oral capsules, or with two inhalations of sodium cromoglycate every eight hours three times a day. Only 8 out of 20 patients (40%) in the forskolin treatment group had asthma attacks during the treatment period, compared to 17 out of 20 patients (85%) in the conventional medication group. In this study, forskolin was more effective than sodium cromoglycate in preventing asthma attacks in patients with mild or moderate persistent asthma. (4) More large, high quality studies are needed to confirm these results.

  • Improve cardiovascular health. The hypotensive and spasmolytic properties of forskolin provide some of its most useful clinical applications. For people at risk, forskolin offers cardioprotective actions that involve lowering blood pressure and improving contractility of the heart. By increasing cAMP levels throughout the cardiovascular system, forskolin helps to relax the arteries and to increase the force of contraction, thereby improving heart function. Several animal and human studies have assessed the efficacy of forskolin in treating hypertension and cardiac failure. Early studies in rats, rabbits and guinea pigs showed forskolin increases the contractile force of heart muscle and relaxation of smooth muscle surrounding the arteries. (5, 6) Confirming these animal studies, a 1987 study of seven human patients with dilated cardiomyopathy showed forskolin improved left ventricular function without increasing energy metabolism. (7) And two further human studies (in 1989 and 1990) showed that intravenous forskolin, starting at 0.5 mcg/kg/minute, increasing at 15 minute intervals to 1.0, 2.0, and 3.0 mcg/kg/minute, is effective in improving cardiac output and pulmonary vessel pressures in patients with idiopathic congestive cardiomyopathy. (8, 9)

    Preliminary evidence also indicates that standardized C. forskohlii extracts (more so than pure forskolin) prevent platelet aggregation and adhesion, which can lead to clogged arteries and blood vessels and cause stroke and/or heart attack. In a 1986 animal model evaluating in vivo inhibition of platelet aggregation, rats were divided into four groups: Group 1 received 480 mg/kg C. forskohlii extract (supplying 20 mg/kg of forskolin); group 2 received 20 mg/kg forskolin; group 3 received the conventional medication dipyridamole; and group 4 served as the control. All treatments were given orally once a day, and ADP-induced platelet aggregation was measured on odd days 1 through 15. All three treatments produced significant inhibition of platelet aggregation. On day 15, the inhibitions were about 42% for group 1, 37% for group 2, and 52% for group 3, indicating the extract of C. forskohlii produced greater inhibition than the pure forskolin. However, neither produced greater inhibition than the conventional drug at these doses. (10) More research is needed in this area.

  • Relieve symptoms of hypothyroidism. A healthy thyroid gland produces hormones that regulate the rate of metabolism. But in hypothyroidism, the thyroid gland can’t secrete enough hormone to be utilized by the cells, and thus, the rate of metabolism – how quickly cells burn energy and make enzymes and proteins needed for bodily functions – slows down. This condition often causes mental and physical sluggishness, which can lead to fatigue, depression, and weight gain.

    Forskolin has traditionally been used in Ayurvedic medicine to treat hypothyroidism and is thought to increase thyroid function by activating the cell-regulating cAMP enzyme and stimulating the release of thyroid hormones. Extensive in vitro and animal studies between 1981 and 2003 showed that forskolin increases thyroid hormone production and stimulates thyroid hormone release; however scientific studies have not yet been conducted to specifically determine the efficacy of forskolin in relieving symptoms of hypothyroidism in humans. Research is needed to determine the role of forskolin in hypothyroidism.

  • Reduce symptoms of psoriasis. Psoriasis is a skin condition characterized by red and inflamed skin, which occurs when skin cells reproduce more quickly than usual (1,000 times greater than normal). This condition seems to be caused by a relative decrease in cAMP levels as compared with cyclic guanine monophosphate (cGMP). Preliminary in vitro studies indicate that forskolin may help to establish the normal balance between cAMP and cGMP, thus reducing symptoms of psoriasis. (11, 12) However, further studies are needed to confirm this effect and indicate a potential benefit in humans.

  • Treat glaucoma. A disease of the optic nerve that leads to loss of vision, glaucoma is often associated with raised intraocular pressure (IOP). Forskolin has been shown to greatly reduce IOP when it is applied directly to the eye, which can be beneficial in treating glaucoma. In the 1980s, preliminary studies in healthy people without eye disease indicated forskolin eye drops can significantly decrease IOP and increase intraocular blood flow without side effects and without inducing miosis (constriction of the pupil). A study published in the Lancet in 1983 indicated a 1% formulation of forskolin eye drops significantly lowered IOP in humans within one hour, reached a peak two hours after treatment, and remained significant for at least five hours. Outflow pressure fell by 70%, on average. (13) And in a 1984 study of eight human subjects who showed a reduction of IOP in response to a single drop of forskolin in one eye, the rate of aqueous humor flow was reduced by an average of 34% compared to no change in the opposite eye during the same time period. No significant change in outflow occurred. (14) However, some studies offered conflicting results. For example, two 1987 studies investigated the effects of forskolin on IOP. In the first study, 1% formulations of forskolin eye drops were compared with placebo in 10 healthy volunteers: no significant differences between the groups were observed after six hours. In a second study with healthy volunteers, only one formulation of 1% forskolin was compared with placebo, and the forskolin formula resulted in a significant reduction in IOP relative to placebo. (15) However, forskolin has not yet been tested in patients with glaucoma. More research is needed to confirm benefits of forskolin in treating this disease.

  • Enhance weight management programs. Limited evidence indicates forskolin’s ability to activate cAMP cells may aid in burning fat, which can lead to weight loss. In vitro studies have shown Forskolin stimulates lipolysis, or the breakdown of stored fat, and inhibits the synthesis of fat by activating cAMP. (16-19) Many obese people often have lower than normal cyclic AMP production, so forskolin supplementation may be a beneficial weight loss aid for these people. In a 2001 study, six overweight women took 25 mg of forskolin (250 mg capsules of 10% standardized forskolin extract) twice a day for eight weeks. At the end of the eight-week trial, the participants lost a mean of ten pounds and reduced their percentage of body fat by nearly 8%. (20) And similarly in men, in a 2005 randomized, double-blind, placebo-controlled study, 30 overweight or obese men took either forskolin (250 mg of 10% forskolin extract) or placebo twice a day for 12 weeks. At the end of the trial, participants taking forskolin showed significant changes in body composition – decreased body fat and fat mass, and increased lean body mass – compared with the placebo group, while at the same time significantly increasing bone mass and serum free testosterone levels in these overweight and obese men. (21) Larger, high quality studies are needed to confirm these beneficial effects as a potential weight management agent.


  • capsule
  • extract
  • IV
  • liquid
  • powder 

Dosage Information

Recommended dosages are based on the level of forskolin content in concentrated and standardized C. forskohlii extracts. For optimal results, use standardized extracts that have known forskolin content in the following dosages: 

  • Forskolin: 5 to 10 mg two to three times a day
  • Standardized extract (18% forskolin): 50 mg two to three times a day
  • Dried root: 2 to 5 g two to three times a day
  • Powder, such as for asthma: 10 mg of forskolin powder, using a Spinhaler inhalator, has been used.
  • Eye drops: 50 microliters of forskolin suspension eye drops (1%) applied topically to the cornea, has been used in healthy people. An appropriate dose for patients with glaucoma is not known.


Guidelines for Use

Forskolin is typically taken over the long-term for hypothyroidism. General recommendations include avoid use in conjunction with thyroid hormone replacement therapy; however the reason for this is unclear.

General Interaction

Forskolin causes the arteries to relax. Because this can lower blood pressure, forskolin should be used in tandem with blood pressure-lowering medications only under a doctor’s supervision. Forskolin relaxes the bronchial muscles and may dangerously increase the potency or action of certain asthma drugs, including albuterol and theophylline. Never alter asthma medication dosages without consulting a doctor first.

Note: For information on interactions with specific drugs, see our WholeHealthMD Drug/Nutrient Interactions Chart.

Possible Side Effects

  • Intravenously, forskolin can cause flushing and hypotension.

  • Inhalation of forskolin can cause throat and upper respiratory tract irritation, mild to moderate cough, tremor, and restlessness.

  • Forskolin eye drop formulations can cause stinging of the eyes and conjunctival hyperemia (redness).


Preliminary findings indicate that for most people, forskolin is safe to take at commonly recommended dosages. However, because forskolin appears to increase the secretion of digestive juices, people with stomach or duodenal ulcers should avoid it. People with low blood pressure should consult a doctor before taking forskolin to avoid complications.


1. Seamon KB, Daly JW. Forskolin: a unique diterpene activator of cyclic AMP-generating systems. J Cyclic Nucleotide Res. 1981;7:201-224.
2. Kaik G, Witte PU. Protective effect of forskolin in acetylcholine provocation in healthy probands. Comparison of 2 doses with fenoterol and placebo. Wien Med Wochenschr. 1986;136:637-641.
3. Bauer K, Dietersdorfer F, Sertl K, et al. Pharmacodynamic effects of inhaled dry powder formulations of fenoterol and colforsin in asthma. Clin Pharmacol Ther. 1993 Jan;53(1):76-83.
4. González-Sánchez R, Trujillo X, Trujillo-Hernández B, et al. Forskolin versus sodium cromoglycate for prevention of asthma attacks: a single-blinded clinical trial. J Int Med Res. 2006 Mar-Apr;34(2):200-7.
5. Dubey MP, Srimal RC, Nityand S, Dhawan BN, Pharmacological studies on coleonol, a hypotensive diterpene from Coleus forskohlii. J Ethnopharmacology. 1981;3:1-13.
6. Lindner E, Dohadwalla AN, Bhattacharya BK. Positive inotropic and blood pressure lowering activity of a diterpene derivative isolated from Coleus forskohlii. Forskolin. Arzneimittelforschung. 1978;28:284-9.
7. Kramer W, Thormann J, Kindler M, Schlepper M. Effects of forskolin on left ventricular function in dilated cardiomyopathy. Arzneimittelforschung. 1987;37:364-367.
8. Schlepper M, Thormann J, Mitrovic V. Cardiovascular effects of forskolin and phosphodiesterase-III inhibitors. Basic Res Cardiol. 1989;84:197-212.
9. Baumann G, Felix S, Sattelberger U, Klein G. Cardiovascular effects of forskolin (HL-362) in patients with idiopathic congestive cardiomyopathy. A comparative study with dobutamine and sodium nitroprusside. J Cardiovasc Pharmacol. 1990;16:93-100.
10. Wysham DG, Brotherton AF, Heistad DD. Effects of forskolin on cerebral blood flow. Implications for a role of adenylate cyclase. Stroke. 1986;17:1299-1303.
11. Ammon HPT, Muller AB. Forskolin: from ayurvedic remedy to a modern agent. Planta Med. 1985;51:473-77.
12, De Vries GW, Amdahl LD, Lowe N, Wheeler LA. Effect of forskolin on beta-adrenergic hyporesponsiveness in skin. Skin Pharmacol. 1988;1(2):106-14.
13. Caprioli J, Sears M. Forskolin lowers intraocular pressure in rabbits, monkeys, and man. Lancet. 1983 Apr 30;1(8331):958-60.
14. Burstein NL, Sears ML, Mead A. Aqueous flow in human eyes is reduced by forskolin, a potent adenylate cyclase activator. Exp Eye Res. 1984 Dec;39(6):745-9.
15. Meyer BH, Stulting AA, Müller FO, et al. The effects of forskolin eye drops on intra-ocular pressure. S Afr Med J. 1987 May 2;71(9):570-1.
16. Allen DO, Quesenberry JT. Quantitative differences in the cyclic AMP-lipolysis relationships for isoproterenol and forskolin. J Pharmacol Exp Ther. 1988;244:852-8.
17. Allen DO, Ahmed B, Naseer K. Relationships between cyclic AMP levels and lipolysis in fat cells after isoproterenol and forskolin. J Pharmacol Exp Ther. 1986;238:659-64.
18. Okuda H, Morimoto C, Tsujita T. Relationship between cyclic AMP production and lipolysis induced by forskolin in rat fat cells. J Lipid Res. 1992;33:225-31.
19. Bianco AC, Kieffer JD, Silva JE. Adenosine 3’,5’-monophosphate and thyroid hormone control of uncoupling protein messenger ribonucleic acid in freshly dispersed brown adipocytes. Endocrinology. 1992;130:2625-33.
20. Badmaev V, Majeed M, Conte A, Parker J. Diterpene Forskolin: A possible new compound for reduction of body weight by increasing lean body mass. Townsend Letter for Doctors and Patients. June 2001;115.
21. Godard MP, Johnson BA, Richmond SR. Body composition and hormonal adaptations associated with forskolin consumption in overweight and obese men. Obes Res. 2005 Aug;13(8):1335-43.

Evidence Based Rating Scale  

The Evidence Based Rating Scale is a tool that helps consumers translate the findings of medical research studies with what our clinical advisors have found to be efficacious in their personal practice. This tool is meant to simplify which supplements and therapies demonstrate promise in the treatment of certain conditions. This scale does not take into account any possible interactions with any medication/ condition/ or therapy which you may be currently undertaking. It is therefore advisable to ask your doctor before starting any new treatment regimen.



















Date Published: 04/18/2005

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