Forskolin extract supplements, safety, side effects, review, health benefit, dose and dosage, 10% 100 mg, interactions and role with yohimbine, aminophylline, cAMP, cyclic AMP
August 12 2014 by Ray Sahelian, M.D.

Coleus forskohlii is an important traditional Ayurvedic herb that has been a part of Indian medicine for centuries.
It has been used for centuries in Ayurvedic medicine to treat various diseases such as hypothyroidism, heart disease and respiratory disorders.  In the 1970s, researchers isolated a chemically active ingredient in the herb and called it forskolin. Now available in supplement form, this substance has been tested in a number of conditions.

buy Forskolin extract supplement - Coleus Forskohlii extract, 60 capsules
Modern extraction and analytical techniques are used to produce the highest quality extract available. Each batch of coleus forskohlii extract is analyzed and guaranteed to contain a minimum of 18% forskolin.

Supplement facts
Coleus Forskohlii root extract - 100 mg
   
Standardized to contain 10% forskolin (10 mg per capsule)

The potent herbal extracts in Passion Rx sexual enhancer include Ashwagandha, Aspallum purificata, Catuaba, Cnidium, Coleus forskohlii forskolin extract, Damiana, Horny goat weed, Maca, Mucuna pruriens, Muira puama, Passion flower, Rehmannia, Rhodiola, Tongkat Ali and Tribulus.

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Suggested use: One capsule forskolin extract once daily before breakfast.

Forskolin supplements and weight loss
Body composition and hormonal adaptations associated with forskolin consumption in overweight and obese men.
Obesity Research. 2005.
This study examined the effect of forskolin on body composition, testosterone, metabolic rate, and blood pressure in overweight and obese men. Thirty subjects were studied in a randomized, double-blind, placebo-controlled study for 12 weeks. Forskolin was shown to elicit favorable changes in body composition by significantly decreasing body fat percentage and fat mass. There was a trend toward a significant increase for lean body mass in the treatment group compared with the placebo group. Oral ingestion (250 mg of 10% forskolin extract twice a day) for a 12-week period was shown to favorably alter body composition while concurrently increasing bone mass and serum free testosterone levels in overweight and obese men.

Biotech Histochem. 2014 Feb 13. The effects of forskolin and rolipram on cAMP, cGMP and free fatty acid levels in diet induced obesity. We investigated the effects of forskolin and rolipram in the diet of animals in which obesity had been induced. We used 50 female albino Wistar rats that were assigned randomly into five groups as follows: group 1, control; group 2, high fat diet; group 3, high fat diet + forskolin; group 4, high fat diet + rolipram; and group 5, high fat diet + rolipram + forskolin. We found that both forskolin and rolipram stimulated lipolysis and inhibited body weight increase by increasing cAMP levels. Also, combination therapy using the two agents may be more effective in preventing diet induced obesity than either agent alone. We found also that these agents did not effect cellular cGMP levels in diet induced obesity.

Forskolin benefits
Over the years studies have shown that it is a platelet aggregation inhibitor, relaxes vascular smooth muscle, decreases intraocular pressure due to glaucoma, and has anti-allergy potential since it inhibits IgE-mediated release of histamine and peptide leukotriene from human basophils and mast cells. Forskolin has been shown to be a potent inhibitor of cancer metastasis in mice injected with malignant cells. In a study in psychiatry, researchers gave it intravenous to four depressed and five schizophrenic patients. All four depressed patients showed a transient mood elevation or stimulation, as did two of the five schizophrenic patients.

This substance may be beneficial as a bronchodilator and anti-allergy agent.
May reduce blood pressure.
It is a United States Food and Drug Administration non-approved vasoactive agent that acts in synergism with prostaglandin E1 to induce smooth muscle relaxation.
In combination with other vasoactive agents, forskolin has demonstrated preliminary safety and efficacy in patients with vascular impotence. See Passion Rx below for a product that has libido boosting properties.

Dosage
Forskolin is available over the counter in pills and liquid in a variety of dosages — most commonly 50 mg coleus forskohlii herbal extract providing 9 mg forskolin and 125 mg coleus forskohlii extract providing 12.5 mg. Research is limited on the appropriate dosages for different conditions.
The forskolin content of coleus root is typically 0.2% to 0.3%, therefore the content of crude coleus products may not be sufficient to produce a pharmacological effect. It is best to use standardized extracts which have it concentrated.
   Coleus forskohlii is available in various extract potencies, for instance 10 percent forskolin, 18 percent, and 20 percent. We are not aware of any research that has tested various extract potencies to determine which is best to use.

Forskolin for allergy
Inhibition of IgE-mediated release of histamine and peptide leukotriene from human basophils and mast cells by forskolin.
Biochem Pharmacol. 1987.
We found that it caused a concentration-related inhibition of IgE-mediated release of histamine and peptide leukotriene C4 (LTC4) from human basophils and lung mast cells. Our data suggest that it modulates the release of mediators of immediate hypersensitivity reactions via the activation of adenylate cyclase in human basophils and mast cells.

Forskolin for asthma
It is still not very clear to me whether this natural extract is effective for asthma. Results of studies have not been very convincing.

J Int Med Res. 2010.
Forskolin compared with beclomethasone for prevention of asthma attacks: a single-blind clinical trial.
Patients with mild or moderately persistent adult asthma were randomly assigned to receive forskolin (one 10-mg capsule orally per day) or beclomethasone (two 50 microg inhalations every 12 h) for 2 months. No statistically significant improvement occurred in any lung function parameter in the forskolin-treated patients. There was no statistically significant difference between both treatment groups for any lung function parameter at baseline or after treatment. None of the beclomethasone-treated patients had an asthma attack and one forskolin-treated patient had a mild asthma attack during the 2-month study period.

Forskolin versus sodium cromoglycate for prevention of asthma attacks: a single-blinded clinical trial.
J Int Med Res. 2006.
Forty patients of either sex with mild persistent or moderate persistent asthma were assigned randomly to 6 months of treatment with forskolin at 10 mg a day orally (capsules) or with two inhalations of sodium cromoglycate every 8 h, three times a day. The number of patients who had asthma attacks during the treatment period was significantly lower among those receiving forskolin than among those receiving sodium cromoglycate.

Relaxant effects of forskolin on guinea pig tracheal smooth muscle.
Lung. 1987.
Forskolin caused dose-dependent relaxant effects on resting tone and on leukotriene C4, leukotriene D4, and carbachol-induced contraction of tracheal smooth muscle. Moreover, with propranolol pretreatment the relaxant effect on tracheal smooth muscle did not change, whereas with the same pretreatment the relaxant effect of isoproterenol diminished. These results suggest that it relaxes airway smooth muscle in guinea pigs in vitro and in vivo by raising tissue cyclic AMP levels and that its actions are independent of beta-adrenoceptors.

Bladder, urinary tract infections
Forskolin may boost the ability of antibiotics to kill E. coli -- the bacteria responsible for 90 percent of bladder infections. In studies in mice, Duke microbiologist Dr. Soman N. Abraham found that E. coli bacteria hide in cells lining the bladder, out of reach of antibiotics. However, when the researchers injected forskolin directly into the bladder or administered it intravenously, it appeared to expel more than 75 percent of "hiding" E. coli, rendering it susceptible to antibiotics. While customary antibiotic treatment kills the vast majority of the bacteria, according to Dr. Soman  Abraham, small numbers of bacteria may survive the antibiotic bath by sneaking into the lining of the bladder. There they lie there until the opportune moment, after antibiotic treatment, to come out and start multiplying again. By revving up cellular activity, forskolin helps flush out bacteria from their niches and into the urine, where they can be killed by antibiotics. Nature Medicine, 2007.
   Comments: Whether forskolin supplements taken orally help individuals with bladder infections is not clear until human trials are done.

Cancer
Forskolin: a potential antimetastatic agent.
Int J Cancer. 1983.
Forskolin is a potent platelet aggregation inhibitor and has been examined for its effects on (a) tumor-induced human platelet aggregation and (b) pulmonary tumor colonization in mice. These studies employed a subline of B16 murine melanoma, B16-F10 (highly metastatic to lungs). Forskolin strongly inhibits the melanoma cell-induced human platelet aggregation. A single dose administered intraperitoneally 30 or 60 min prior to tail vein injection of cultured B16-F10 cells reduced tumor colonization in the lungs by more than 70%. These findings raise the possibility that forskolin could prove of value in the clinic for the prevention of cancer metastasis.

Forskolin extract and impotence
One study evaluated the role of forskolin as an injection into the corpus cavernosum of the penis. In many cases there was improvement in rigidity and/or erection.

Intracavernosal forskolin: role in management of vasculogenic impotence resistant to standard 3-agent pharmacotherapy.
J Urol 1997.
We investigated forskolin, a direct adenylate cyclase activator, as an intracavernosal vasoactive agent in management of vasculogenic impotence. Concentration responses for forskolin and prostaglandin E1 induced relaxation of phenylephrine precontracted strips of human corpus cavernosum smooth muscle were constructed in vitro. Cyclic adenosine monophosphate (cAMP) synthesis was determined with papaverine, phentolamine, prostaglandin E1 and forskolin in human corpus cavernosum smooth muscle cell cultures. In vitro forskolin and prostaglandin E1 alone caused concentration dependent relaxation. Clinical investigation in 31 patients showed no adverse events. Overall 61% reported improvement in rigidity and/or erection duration using intracavernosal forskolin, papaverine, phentolamine and prostaglandin E1. Forskolin acts in synergism with prostaglandin E1 to induce smooth muscle relaxation. In combination with other vasoactive agents, forskolin has demonstrated preliminary safety and efficacy in patients with vasculogenic impotence resistant to standard 3-agent pharmacotherapy.

Gastric tissue
Isolated gastric glands were used to investigate the action of forskolin, a novel diterpene extracted from the Indian plant Coleus forskohlii. Forskolin was found to stimulate both acid formation and pepsinogen secretion. The stimulation was rapid, reversible and dose dependent. The efficacy of forskolin was similar to that of more commonly used secretagogues, e.g. histamine, carbachol, cyclic AMP derivatives. Forskolin was found to be more effective in activating adenyl cyclase than histamine, isoproterenol or NaF. Treatment of gastric glands with forskolin resulted in a 100-fold increase in tissue cAMP levels, supporting the idea that forskolin activates adenyl cyclase in the intact cell. The results are interpreted to show that forskolin stimulation of gastric secretions is due to activation of adenyl cyclase with a consequent increase in tissue cAMP.

Glaucoma
Forskolin: upcoming antiglaucoma molecule.
J Postgrad Med. 2012. Department of Pharmaceutics, R. C. Patel Institute of Pharmaceutical Education and Research, Near Karwand Naka, Shirpur, Maharashtra, India.
Forskolin is the first pharmaceutical drug and product derived from a plant to be approved in India by the DCGI in 2006. It is a lipid-soluble compound that can penetrate cell membranes and stimulates the enzyme adenylate cyclase which, in turn, stimulates ciliary epithelium to activate cyclic adenosine monophosphate, which decreases intraocular pressure (IOP) by reducing aqueous humor inflow. The topical application is capable of reducing IOP in rabbits, monkeys, and humans. In its drug interactions, it may act synergistically with epinephrine, ephedrine and pseudoephedrine. Whereas the effects of anti-clotting medications like warfarin, clopidogre, aspirin, anoxaparin, etc., may be enhanced by forskolin. This medicine is contraindicated in the medications for people with ulcers as forskolin may increase acid level.

Forskolin lowers intraocular pressure by reducing aqueous inflow.
Invest Ophthalmol Visual Sci. 1984.
Forskolin lowers the intraocular pressure of rabbits, monkeys, and humans. In rabbits, net aqueous humor inflow decreases, outflow facility remains unchanged, and ciliary blood flow increases. Tolerance to the intraocular pressure lowering effect did not occur in rabbits after topical doses given every 6 hr for 15 days. In vitro forskolin activates adenylate cyclase of crude particulate homogenates prepared from cultured human ciliary epithelia or from dissected ciliary epithelial processes of rabbit or human eyes. This activation is not blocked by timolol. The stimulation of adenylate cyclase by isoproterenol in vitro is potentiated in the presence of forskolin. This substance represents a potentially useful class of glaucoma treating agents differing in molecular mechanism of action from previously used drugs.

The eye drops are not currently available in the USA or anyplace else that I know of except Samilabs in India.

Q. I read that forskolin reduces intraocular pressure and this makes me cautious about using this for erectile dysfunction. Would using it affect my eyes in any negative way since it does this? Is it true that it does this?
   A. At this time I am not sure how much of any effect it has on intraocular pressure when taken as a pill in the low dosages available as a supplement.

Heart muscle
Forskolin exerts its actions on cells by directly activating the catalytic subunit of adenylatecyclases. The primary effect on heart muscles is the positive inotropic one, at higher forskolin concentrations, an acceleration of the pacemaker activity can be observed. External calcium is required for this augmentation of contraction. Verapamil, prenylamine and tetrodotoxin depress these effects.

Hypertension
Does forskolin extract supplement reduce blood pressure?
   We have not seen any definitive research evaluating forskolin supplements and hypertension in humans.

Mechanism of action
Forskolin is a diterpene which directly activates the adenylate cyclase and raises cyclic AMP levels in a variety of tissues.
Cyclic AMP is an important cell regulating compound. Once formed it activates many other enzymes involved in diverse cellular functions. Under normal situations cAMP is formed when a stimulatory hormone (e.g., epinephrine) binds to a receptor site on the cell membrane and stimulates the activation of adenylate cyclase. This enzyme is incorporated into all cellular membranes and only the specificity of the receptor determines which hormone will activate it in a particular cell. Forskolin appears to bypass this need for direct hormonal activation of adenylate cyclase. As a result of this direct activation of adenylate cyclase, intracellular cAMP levels rise. The physiological and biochemical effects of a raised intracellular cAMP level include: inhibition of platelet activation; inhibition of mast cell degranulation and histamine release; increased force of contraction of heart muscle; relaxation of the arteries and other smooth muscles; increased insulin secretion; and increased thyroid function.

Review and summary
With so many interesting possibilities, forskolin will likely be continued to be studied for a long time. Unfortunately, at this point in time, we don't know enough about forskolin to know for certain which clinical conditions it can be used effectively and safely.

Drug interaction
Q. I am writing with a question about your review of this herbal supplement on your site. I am 61 year old very active male, who runs, bikes and walks four days a week. I have taken Sectral for about 20 years for a benign irregular heart beat. I got the impression from your review that forskolin might interfere with those types of drugs. I am incorrect?
   A. It is difficult to say since I have not seen any studies regarding its interaction with different types of prescription medications.

Topical forskolin
Treatment with forskolin can promote skin pigmentation and protect against the UV light-induced damage. Fair-skinned individuals do not tan when exposed to UV light due to a defective melanocortin 1 receptor (MC1R) gene -- one of several genes that regulate skin, hair and eye color. The gene plays a key role in determining if a person has red hair, light skin and sensitivity to UV light. However, a functional MC1R is not required to achieve skin pigmentation. Dr. David E. Fisher, from the Dana Farber Cancer Institute in Boston, and colleagues investigated the effects of UV light in mice lacking a working MC1R gene. UV light exposure induced melanocyte stimulating hormone expression in keratinocytes (skin cells) of these red / blonde-haired mice, but pigmentation did not take place. Melanocytes are a type of skin cells that produce pigment. Topical application of forskolin, however, caused pigmentation to occur without the need for UV light, showing that functional MC1R is, in fact, not required. Forskolin treatment protected the animals from UV light-induced skin DNA damage. Nature, 2006.

Research
Induction of Drug Metabolism by Forskolin, the Role of The Pregnane X Receptor and the PKA Signal Transduction Pathway.
J Pharmacol Exp Ther. 2004

Emails
Just want to know if there is any evidence of tolerance in the continued administration. It seems that there are a number of beneficial effects, including enhanced exercise tolerance. I have been taking Tenormin for years and forskolin definitely helps. My brother in law is a physician and he wondered if forskolin is something that I should cycle on and off of. Can't find mention of tolerance to forskolin on the internet.
   The reason there is little info is because there is hardly any human studies published with the use of forskolin supplements for prolonged periods, so we really don't know at this time.

Please tell me if the forskolin supplement contains anything other than this ingredient, such as an amino acid that might increase blood pressure.
    The herb coleus forskohlii has a number of other substances that have not been well-studied in terms of their effect on blood pressure.