{"url":"https://whatshealthyandwhy.com/coleus-forskohlii/camp-signaling-body-composition-and-glaucoma","path":"/coleus-forskohlii/camp-signaling-body-composition-and-glaucoma","alternates":{"json":"https://whatshealthyandwhy.com/api/articles/coleus-forskohlii/camp-signaling-body-composition-and-glaucoma.json","markdown":"https://whatshealthyandwhy.com/coleus-forskohlii/camp-signaling-body-composition-and-glaucoma.md"},"topic":{"slug":"coleus-forskohlii","name":"Coleus forskohlii","url":"https://whatshealthyandwhy.com/coleus-forskohlii"},"slug":"camp-signaling-body-composition-and-glaucoma","order":1,"title":"cAMP Signaling, Body Composition, and Glaucoma","question":"Does Coleus forskohlii (forskolin) help with fat loss or glaucoma?","answer":"Forskolin may reduce body fat in overweight men and lower eye pressure in glaucoma, but trials are small and women saw no fat loss.","description":"How forskolin, the active diterpene from Coleus forskohlii root, activates adenylate cyclase to raise cellular cAMP — with clinical evidence for fat loss, testosterone support, and intraocular pressure reduction in glaucoma","confidence":2,"confidenceNote":"Placebo-controlled trials had only 23–30 people and gave different results in men and women; glaucoma data are one open-label study and one add-on trial.","evidenceSummary":{"rctCount":3,"observationalCount":2,"metaAnalysisCount":0,"totalParticipants":"~270","replicated":false,"newestStudyYear":2015},"category":{"categoryTitle":"What's Good For You","categorySlug":"good-for-you","subcategoryName":"Herbs & Spices","subcategorySlug":"herbs","url":"https://whatshealthyandwhy.com/explore/good-for-you/herbs"},"actions":["Body-composition trials used 250 mg of a 10% forskolin extract twice daily for 12 weeks [1][2][3].","For glaucoma, use only under eye-doctor supervision: trials used 1% drops, or oral forskolin plus rutin added to medication [4][5].","In the metabolic syndrome trial everyone followed a reduced-calorie diet, and forskolin additionally improved insulin resistance [3]."],"cautions":["It may lower blood pressure, so people taking antihypertensive medications should ask their doctor first.","In women the trial found no fat-loss benefit, only less weight gain than placebo [2].","Glaucoma evidence is open-label or add-on, so do not replace prescribed eye drops [4][5]."],"simpleText":"Coleus forskohlii is a plant native to India used for centuries in Ayurvedic medicine. Its root contains a unique diterpene compound called forskolin, which has a rare ability to directly activate adenylate cyclase — the enzyme that produces cyclic AMP (cAMP) inside cells [1]. Because cAMP is a fundamental signaling molecule that governs fat breakdown, hormone release, and fluid regulation throughout the body, forskolin can produce effects across multiple systems simultaneously. Clinical trials show it reduces body fat and improves testosterone levels in overweight men, helps mitigate weight gain in women, improves insulin sensitivity in metabolic syndrome, and meaningfully lowers intraocular pressure in glaucoma patients [1][2][3][4]. Standardized root extracts (typically 10% forskolin) are the form used in research.","mediumText":"How Forskolin Works: The cAMP Pathway\n\nCyclic adenosine monophosphate (cAMP) is one of the body's most important second messengers — a molecular relay signal that carries instructions from the cell surface into the interior. When a hormone binds a receptor on the outside of a cell, adenylate cyclase converts ATP into cAMP inside the cell, which then activates protein kinase A (PKA) and triggers downstream processes: lipolysis (fat breakdown), thyroid hormone synthesis, testosterone production in Leydig cells, and aqueous humor regulation in the eye.\n\nMost compounds that raise cAMP do so indirectly, by binding to receptors that stimulate adenylate cyclase. Forskolin is unusual: it acts directly on the catalytic subunit of adenylate cyclase itself, bypassing the receptor entirely [1]. This means it can activate cAMP signaling in tissues regardless of whether the usual hormonal signals are present or functioning normally — a property that makes it relevant when receptor sensitivity is blunted, such as in obesity, insulin resistance, or aging.\n\nBody Composition: Fat Loss and Testosterone\n\nThe clinical evidence for forskolin and body composition is moderate and sex-specific.\n\nIn overweight men: A 12-week, double-blind, randomized placebo-controlled trial (Godard et al., 2005) gave 30 overweight and obese men either 250 mg of a 10% standardized C. forskohlii extract or placebo twice daily [1]. The forskolin group showed a significant decrease in body fat percentage and absolute fat mass by DEXA scan compared to the placebo group. Lean body mass was preserved. Serum free testosterone increased significantly in the treatment group — consistent with forskolin's known stimulation of cAMP in testicular Leydig cells, which is the primary signaling step for luteinizing hormone (LH)-driven testosterone synthesis. Bone mineral density also trended higher in the treatment group.\n\nIn overweight women: A parallel 12-week RCT (Henderson et al., 2005) using the same 250 mg twice-daily dose in 23 mildly overweight women found different results [2]. There was no significant difference in fat loss between groups. However, women in the forskolin group gained significantly less weight than the placebo group over the study period — suggesting a weight-stabilizing rather than weight-reducing effect in this population. Blood markers, including lipid panels and liver enzymes, remained normal in both groups throughout.\n\nThe sex difference in response is consistent with cAMP's role in testosterone synthesis being specific to the male endocrine system. Women do not have the same testicular cAMP-testosterone axis, and the lipolytic stimulus may require a higher forskolin dose or longer duration to overcome differences in fat tissue receptor density in women.\n\nMetabolic Syndrome and Insulin Sensitivity\n\nA 2015 randomized controlled trial (Loftus et al.) tested 250 mg of C. forskohlii extract twice daily in overweight and obese adults following a calorie-restricted diet for 12 weeks [3]. Both groups lost weight and reduced waist and hip circumference. The key difference was in insulin metabolism: the C. forskohlii group showed significantly improved insulin concentration and insulin resistance (HOMA-IR) compared to the placebo group. HDL cholesterol rose in both groups, but more in the treatment group.\n\nThe insulin-sensitizing effect is plausible mechanistically: cAMP signaling modulates GLUT4 glucose transporter activity and improves insulin receptor signaling. Chronic low-grade inflammation in adipose tissue also reduces cAMP responsiveness; forskolin's direct activation bypasses this impairment.\n\nGlaucoma and Intraocular Pressure\n\nForskolin has a well-established role in glaucoma management — distinct from its use as an oral supplement — backed by both basic science and clinical evidence.\n\nIntraocular pressure (IOP) is regulated by the rate at which aqueous humor (the fluid inside the eye) is produced by the ciliary epithelium and drained through the trabecular meshwork. cAMP signaling in the ciliary epithelium reduces aqueous humor production. Topical forskolin eye drops activate this pathway directly, reducing fluid inflow and lowering IOP.\n\nA 2015 open-label clinical study (Majeed et al.) enrolled 90 patients with open-angle glaucoma (IOP > 24 mmHg) and treated them with 1% forskolin eye drops three times daily for four weeks [4]. IOP fell progressively from baseline across all measurement visits. The authors noted that this represents a clinically meaningful alternative or adjunct to beta-blocker eye drops — particularly valuable for glaucoma patients who have concomitant asthma, since beta-blockers (the most common topical glaucoma treatment) are contraindicated in asthma.\n\nA separate Italian multi-centre trial (Vetrugno et al., 2012) added oral forskolin and rutin supplementation to 52 glaucoma patients who were already on maximum tolerated medical therapy [5]. Even in this medically managed group, the additional supplement produced a further 10% reduction in IOP — rising to 15% in patients with IOP at or above 21 mmHg at enrollment. This is notable because adding any measurable IOP reduction to patients who are already on maximum pharmaceutical therapy is clinically significant, as each mmHg of sustained IOP reduction reduces glaucoma progression risk.\n\nPractical Use\n\nForm | Dose | Notes\n\nOral extract capsules (10% standardized) | 250 mg twice daily | Form used in body composition RCTs\nTopical 1% eye drops | 2 drops three times daily | For glaucoma — use only under ophthalmic supervision\nOral combination (with rutin) | Per product dosing | Evidence as adjunct to glaucoma medications\n\nFor body composition, trials ran 12 weeks with consistent daily dosing. Forskolin is generally well tolerated — no serious adverse events were reported in published clinical trials. It may lower blood pressure (a cAMP-mediated effect on vascular smooth muscle), which is a consideration for those already on antihypertensive medications. The glaucoma application requires ophthalmological supervision.\n\nSee our Thyroid Health page for more on how cAMP signaling intersects with thyroid hormone production, and our Testosterone and Longevity page for complementary approaches to androgen support.","deepText":"Evidence Review\n\nMechanism: Direct Adenylate Cyclase Activation\n\nForskolin's pharmacology is unusual among plant compounds. Most phytochemicals that influence hormonal or metabolic pathways do so through receptor binding, enzyme inhibition, or antioxidant activity. Forskolin acts on the catalytic unit of adenylate cyclase directly, producing intracellular cAMP accumulation in a receptor-independent manner. This was established in foundational biochemistry research and underlies all subsequent clinical applications. In thyroid tissue, this mechanism recapitulates the effects of thyroid-stimulating hormone (TSH) without requiring TSH receptor activation. In testicular Leydig cells, it activates the same cAMP-PKA pathway used by luteinizing hormone (LH) to drive testosterone synthesis. In the ciliary epithelium of the eye, it suppresses aqueous humor formation by the same mechanism used by endogenous prostaglandins and beta-adrenergic signaling.\n\nClinical Trial: Body Composition and Testosterone in Men (Godard et al., 2005)\n\nGodard, Johnson, and Richmond (2005) conducted the most-cited clinical trial of oral forskolin, published in Obesity Research [1]. Thirty overweight or obese men (BMI > 26) were randomized to 250 mg of a 10% C. forskohlii extract or placebo twice daily for 12 weeks in a double-blind design. Body composition was assessed by dual-energy X-ray absorptiometry (DEXA), considered the clinical gold standard for fat mass and lean mass measurement.\n\nResults: The forskolin group showed a statistically significant decrease in body fat percentage (p=0.05) and fat mass (p=0.04) compared to placebo, with lean body mass preserved. Serum free testosterone increased significantly in the treatment group relative to placebo (p=0.01) — an effect consistent with cAMP's established role as the primary intracellular signal for testosterone biosynthesis in Leydig cells. Resting metabolic rate (indirect calorimetry) and arterial blood pressure did not change significantly in either group. Bone mineral density trended higher in the treatment group but did not reach significance over the 12-week window. Importantly, no clinically adverse laboratory findings (liver enzymes, lipids, complete blood count) were recorded in either group.\n\nLimitations: The sample size was small (n=30), limiting statistical power for secondary outcomes. The study was not pre-registered, and results have not been fully replicated in a larger independent trial.\n\nClinical Trial: Body Composition in Women (Henderson et al., 2005)\n\nHenderson and colleagues at Baylor University's Exercise and Sport Nutrition Laboratory ran a parallel 12-week RCT in 23 mildly overweight women, using the same 250 mg twice-daily dose of ForsLean™ (10% C. forskohlii extract standardized brand) [2]. DEXA, body weight, dietary intake, and psychometric measures were collected at 0, 4, 8, and 12 weeks. Fasting blood panels were drawn at 0 and 12 weeks.\n\nResults: There was no significant difference in fat mass reduction between the forskolin and placebo groups. However, the placebo group gained weight over the 12-week period while the forskolin group did not — a significant between-group difference in weight change. Blood chemistry including lipid profiles, liver function tests, renal markers, and complete blood count remained normal in both groups throughout. No adverse events were reported. The authors concluded that C. forskohlii extract does not appear to promote active fat loss in mildly overweight women but may attenuate weight gain — a meaningful, if more modest, clinical finding.\n\nThe sex difference in response is consistent with the absence of the testicular cAMP-testosterone axis in women; the lipolytic effects of cAMP in adipose tissue were not sufficient to produce significant fat loss at this dose in a female population without caloric restriction as an additional variable.\n\nRandomized Controlled Trial: Metabolic Syndrome (Loftus et al., 2015)\n\nLoftus, Astell, Mathai, and Su (2015) published what is currently the most methodologically robust human trial of C. forskohlii in the journal Nutrients [3]. Thirty overweight or obese adults with at least three features of metabolic syndrome were randomized to 250 mg of C. forskohlii extract or placebo twice daily for 12 weeks, with all participants simultaneously following a medically supervised hypocaloric diet. Primary outcomes included anthropometric measures, lipid panel, fasting insulin, and insulin resistance (HOMA-IR).\n\nBoth groups lost weight and reduced waist and hip circumference, consistent with the hypocaloric diet effect. The distinguishing findings were in metabolic parameters: fasting insulin concentration decreased significantly more in the C. forskohlii group (p=0.049), and HOMA-IR (a validated index of insulin resistance) improved significantly more in the treatment group (p=0.035). HDL cholesterol rose in both groups but numerically more in the treatment arm. These findings suggest that at least part of forskolin's value may lie not in direct fat mobilization but in improving insulin sensitivity — an effect mediated plausibly through cAMP's influence on GLUT4 translocation and adipocyte insulin receptor signaling.\n\nLimitations: Small sample (n=30), single-centre, relatively short duration. The co-intervention (hypocaloric diet) makes it difficult to isolate the supplement's independent effect on weight outcomes.\n\nGlaucoma: Open-Label Eye Drop Study (Majeed et al., 2015)\n\nMajeed and colleagues conducted an open-label clinical study of 1% topical forskolin eye drops in 90 patients with primary open-angle glaucoma and IOP above 24 mmHg [4]. Patients instilled 2 drops three times daily, with IOP measured at baseline and at weeks 1, 2, 3, and 4. IOP fell progressively across all follow-up visits. The reduction was clinically meaningful and comparable to the class effect of topical beta-blockers. …","deepTruncated":true,"references":[{"id":"1","title":"Body composition and hormonal adaptations associated with forskolin consumption in overweight and obese men","authors":"Godard MP, Johnson BA, Richmond SR","year":2005,"journal":"Obesity Research","pmid":"16129715","url":"https://pubmed.ncbi.nlm.nih.gov/16129715/"},{"id":"2","title":"Effects of coleus forskohlii supplementation on body composition and hematological profiles in mildly overweight women","authors":"Henderson S, Magu B, Rasmussen C, Lancaster S, Kerksick C, Smith P, Melton C, Cowan P, Greenwood M, Earnest C, Almada A, Milnor P, Magrans T, Bowden R, Ounpraseuth S, Thomas A, Kreider RB","year":2005,"journal":"Journal of the International Society of Sports Nutrition","pmid":"18500958","url":"https://pubmed.ncbi.nlm.nih.gov/18500958/"},{"id":"3","title":"Coleus forskohlii Extract Supplementation in Conjunction with a Hypocaloric Diet Reduces the Risk Factors of Metabolic Syndrome in Overweight and Obese Subjects: A Randomized Controlled Trial","authors":"Loftus HL, Astell KJ, Mathai ML, Su XQ","year":2015,"journal":"Nutrients","pmid":"26593941","url":"https://pubmed.ncbi.nlm.nih.gov/26593941/"},{"id":"4","title":"Efficacy and safety of 1% forskolin eye drops in open angle glaucoma - An open label study","authors":"Majeed M, Nagabhushanam K, Natarajan S, Vaidyanathan P, Karri SK, Jose JA","year":2015,"journal":"Saudi Journal of Ophthalmology","pmid":"26155078","url":"https://pubmed.ncbi.nlm.nih.gov/26155078/"},{"id":"5","title":"Oral administration of forskolin and rutin contributes to intraocular pressure control in primary open angle glaucoma patients under maximum tolerated medical therapy","authors":"Vetrugno M, Uva MG, Russo V, Lester M, Ciancaglini M, Brusini P, Centofanti M, Rossetti LM","year":2012,"journal":"Journal of Ocular Pharmacology and Therapeutics","pmid":"22731245","url":"https://pubmed.ncbi.nlm.nih.gov/22731245/"}],"wordCount":2257,"source":{"path":"src/content/topics/coleus-forskohlii/camp-signaling-body-composition-and-glaucoma.md"},"citeAs":"“Does Coleus forskohlii (forskolin) help with fat loss or glaucoma?.” What's Healthy and Why. https://whatshealthyandwhy.com/coleus-forskohlii/camp-signaling-body-composition-and-glaucoma","notice":"General information backed by peer-reviewed research, not medical advice."}