{"shortAnswer":"Sildenafil is FDA-approved as Viagra for erectile dysfunction and as Revatio for high blood pressure in the lungs. For those uses the evidence grade is strong-human. Taken with nitrate heart drugs, it can drop blood pressure to dangerous levels. FDA keeps finding it hidden in sexual enhancement products.","url":"https://peptideindex.ai/compound/sildenafil","status":"fda-approved","statusCheckedAt":"2026-10-26T13:43:51.824Z","statusStale":false,"regulatoryAsOf":"2026-10-26","verified":"2026-10-26T13:43:51.859Z","primarySourceUrl":"https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=020895","clinicallyReviewed":false,"notice":"Information, not medical advice.","id":"a4b6768a-9e87-4571-ac18-6341550d36dd","object":"compound","slug":"sildenafil","name":"Sildenafil","attrs":{"name":"Sildenafil","class":"non-peptide","access":[{"type":"approved-product","detail":"Approved by FDA as a prescription tablet for erectile dysfunction.","indication":"Treatment of erectile dysfunction.","source_url":"https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=020895","brand_names":["Viagra"],"manufacturer":"Viatris"},{"type":"approved-product","detail":"Approved by FDA as a prescription tablet, liquid and shot for high blood pressure in the lungs.","indication":"Treatment of pulmonary arterial hypertension (WHO Group I) in adults, and in children 1 to 17 years old.","source_url":"https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=021845","brand_names":["Revatio"],"manufacturer":"Viatris"},{"type":"lawful-compounding","detail":"Pharmacies may compound with a raw substance that meets a USP standard or is part of an FDA-approved drug.","source_url":"https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act"}],"dosing":"From the Viagra and Revatio labels. For erectile dysfunction, most men take 50 mg about 1 hour before sex, as needed, no more than once a day. The dose may go up to 100 mg or down to 25 mg. For high blood pressure in the lungs, adults take 20 mg by mouth three times a day, which may be raised to 80 mg three times a day. Adults may instead get 10 mg as a shot into a vein three times a day. Children 1 to 17 years old take 10 mg or 20 mg three times a day, by weight. The prescriber sets the dose.","trials":[{"nct":"NCT06800092","url":"https://clinicaltrials.gov/study/NCT06800092","phase":"Phase 2/Phase 3","title":"Sildenafil to Prevent and Reduce Cancer Related Cognitive Impairment","status":"not-yet-recruiting","sponsor":"The University of Texas Medical Branch, Galveston","countries":["United States"],"us_states":["Texas"]},{"nct":"NCT07039760","url":"https://clinicaltrials.gov/study/NCT07039760","phase":"Early phase 1","title":"Asciminib With or Without Sildenafil for Brain Tumors","status":"not-yet-recruiting","sponsor":"Washington University School of Medicine","countries":["United States"],"us_states":["Missouri"]},{"nct":"NCT07647003","url":"https://clinicaltrials.gov/study/NCT07647003","phase":"Phase 2","title":"A Study to Evaluate the Effect of Two Fixed-Dose Leucine, Sildenafil and Metformin Combinations on Blood Pressure in Individuals With Hypertension","status":"not-yet-recruiting","sponsor":"NuSirt Biopharma","countries":[],"us_states":[]},{"nct":"NCT06810284","url":"https://clinicaltrials.gov/study/NCT06810284","phase":"Phase 2","title":"Sildenafil Plus Hypothermia to Treat Neonatal Encephalopathy","status":"not-yet-recruiting","sponsor":"Assistance Publique - Hôpitaux de Paris","countries":["France"],"us_states":[]},{"nct":"NCT07508358","url":"https://clinicaltrials.gov/study/NCT07508358","phase":"Phase 1","title":"Vaginal Sildenafil for Primary Dysmenorrhea","status":"not-yet-recruiting","sponsor":"Kevin Hellman","countries":["United States"],"us_states":["Illinois"]},{"nct":"NCT07824674","url":"https://clinicaltrials.gov/study/NCT07824674","phase":"Phase 2/Phase 3","title":"The Effect of Additive On-Demand Sildenafil vs. Dextrose Candy on Maximum Exercise Capacity in Pulmonary Arterial Hypertension","status":"recruiting","sponsor":"Silvia Ulrich","countries":["Switzerland"],"us_states":[]},{"nct":"NCT07732387","url":"https://clinicaltrials.gov/study/NCT07732387","phase":"Phase 1","title":"A Study to Assess the Safety, Tolerability and Pharmacokinetics of Viaca (Sildenafil + Cabergoline) Compared With Sildenafil and Cabergoline","status":"not-yet-recruiting","sponsor":"Yanping Kong","countries":["Australia"],"us_states":[]},{"nct":"NCT07713914","url":"https://clinicaltrials.gov/study/NCT07713914","phase":"Phase 4","title":"Randomized Study of Triple Therapy vs Sildenafil Dose Optimization in Pulmonary Arterial Hypertension","status":"recruiting","sponsor":"University of Sao Paulo General Hospital","countries":["Brazil"],"us_states":[]},{"nct":"NCT07536880","url":"https://clinicaltrials.gov/study/NCT07536880","phase":"Not stated","title":"Effect of Sildenafil on Left Ventricular Function in Pediatric With Primary Dilated Cardiomyopathy","status":"not-yet-recruiting","sponsor":"Assiut University","countries":[],"us_states":[]},{"nct":"NCT07601646","url":"https://clinicaltrials.gov/study/NCT07601646","phase":"Phase 2","title":"A Single-Arm, Dose Escalation of an Intraurethral Alprostadil Paste for Erectile Dysfunction","status":"recruiting","sponsor":"Ryan Flannigan, MD","countries":["Canada"],"us_states":[]},{"nct":"NCT07290400","url":"https://clinicaltrials.gov/study/NCT07290400","phase":"Phase 2","title":"Effect of Moderate Alcohol on Absorption and Onset of Hezkue Sildenafil Suspension","status":"not-yet-recruiting","sponsor":"Aspargo Labs, Inc","countries":[],"us_states":[]},{"nct":"NCT07302698","url":"https://clinicaltrials.gov/study/NCT07302698","phase":"Phase 1","title":"PK and Onset of Hezkue Oral Sildenafil Suspension After Alcohol Consumption","status":"not-yet-recruiting","sponsor":"Aspargo Labs, Inc","countries":[],"us_states":[]},{"nct":"NCT07117383","url":"https://clinicaltrials.gov/study/NCT07117383","phase":"Phase 1","title":"Hezkue®, Hezkue Turbo®, and Commercial Sildenafil Products in Fed Healthy Male Subject","status":"not-yet-recruiting","sponsor":"Aspargo Labs, Inc","countries":["United States"],"us_states":["New York"]},{"nct":"NCT07231185","url":"https://clinicaltrials.gov/study/NCT07231185","phase":"Phase 2","title":"Phase 2 Efficacy Study of Sildenafil Products in Adult Men With Erectile Dysfunction","status":"not-yet-recruiting","sponsor":"Aspargo Labs, Inc","countries":[],"us_states":[]},{"nct":"NCT07391579","url":"https://clinicaltrials.gov/study/NCT07391579","phase":"Phase 4","title":"Daily Tadalafil 5 mg Combined With On-Demand Sildenafil 100 mg for Treatment of Erectile Dysfunction in PDE-5I Non Responder Patients","status":"recruiting","sponsor":"Mansoura University","countries":["Egypt"],"us_states":[]},{"nct":"NCT07177326","url":"https://clinicaltrials.gov/study/NCT07177326","phase":"Phase 3","title":"Combination Therapy of Tadalafil 2.5mg Plus Sildenafil 25mg Versus Tadalafil 5 mg Monotherapy for Treatment of Erectile Dysfunction: A Randomized, Placebo-Controlled Double-Blinded Cross-Over Study","status":"not-yet-recruiting","sponsor":"Assiut University","countries":[],"us_states":[]},{"nct":"NCT06123156","url":"https://clinicaltrials.gov/study/NCT06123156","phase":"Phase 3","title":"Interest of Early Erectile Rehabilitation With Sildenafil After Radiotherapy and Proctectomy for Rectal Cancer","status":"recruiting","sponsor":"University Hospital, Rouen","countries":["France"],"us_states":[]},{"nct":"NCT07057011","url":"https://clinicaltrials.gov/study/NCT07057011","phase":"Not applicable","title":"Therapeutic Outcomes of Selective Serotonin Reuptake Inhibitors and Phosphodiesterase-5 Inhibitors Combination Therapy Versus Monotherapy","status":"not-yet-recruiting","sponsor":"South Valley University","countries":["Egypt"],"us_states":[]},{"nct":"NCT06839651","url":"https://clinicaltrials.gov/study/NCT06839651","phase":"Phase 1","title":"Umbilical Cord Mesenchymal Stem Cell Secretome in Severe Erectile Dysfunction Non-responsive to Sildenafil","status":"not-yet-recruiting","sponsor":"Universitas Indonesia","countries":[],"us_states":[]},{"nct":"NCT06872866","url":"https://clinicaltrials.gov/study/NCT06872866","phase":"Phase 1","title":"The Objective of This Phase 1 Study is to Evaluate the Food Effect of 100 mg Hezkue Turbo® (ASP-001.1, Sildenafil) Under Fed Versus 100 mg of Hezkue Turbo® (ASP-001.1, Sildenafil) Under Fasted Conditions in Healthy Adult Male Subjects","status":"recruiting","sponsor":"Aspargo Labs, Inc","countries":["United States"],"us_states":["New York"]},{"nct":"NCT06510322","url":"https://clinicaltrials.gov/study/NCT06510322","phase":"Early phase 1","title":"Sildenafil to Reduce Vascular Remodeling During Left Ventricular Assist Device Support","status":"recruiting","sponsor":"Montefiore Medical Center","countries":["United States"],"us_states":["New York"]},{"nct":"NCT06797479","url":"https://clinicaltrials.gov/study/NCT06797479","phase":"Not stated","title":"Detection of Circulating Therapeutic Monoclonal Antibodies in Biological Samples of Gynecological Cancer Patients.","status":"not-yet-recruiting","sponsor":"Fondazione Policlinico Universitario Agostino Gemelli IRCCS","countries":[],"us_states":[]},{"nct":"NCT06954597","url":"https://clinicaltrials.gov/study/NCT06954597","phase":"Phase 2","title":"Safety and Tolerability of TOP-N53 Applied on Digital Ulcers in Patients With Systemic Sclerosis","status":"recruiting","sponsor":"Topadur Pharma AG","countries":["France","Switzerland"],"us_states":[]},{"nct":"NCT06782659","url":"https://clinicaltrials.gov/study/NCT06782659","phase":"Phase 1","title":"Study to Compare the Effects of Viagra® Vs Hezkue® in Healthy Fasted Male Participants.","status":"not-yet-recruiting","sponsor":"Aspargo Labs, Inc","countries":["United States"],"us_states":["Florida"]},{"nct":"NCT06753981","url":"https://clinicaltrials.gov/study/NCT06753981","phase":"Not stated","title":"Efficacy and Safety of Triple-targeted Drug Therapy in Treatment-naive Patients With Non-low-risk PAH: A Real-world, Multicenter Study","status":"recruiting","sponsor":"Qianfoshan Hospital","countries":["China"],"us_states":[]},{"nct":"NCT06715280","url":"https://clinicaltrials.gov/study/NCT06715280","phase":"Phase 4","title":"Switching of Sildenafil to Riociguat in CTEPH Patients","status":"recruiting","sponsor":"Chinese University of Hong Kong","countries":["Hong Kong"],"us_states":[]},{"nct":"NCT05782244","url":"https://clinicaltrials.gov/study/NCT05782244","phase":"Phase 2","title":"Sildenafil for Microvasculopathy in Chronic TBI","status":"recruiting","sponsor":"University of Pennsylvania","countries":["United States"],"us_states":["Pennsylvania"]},{"nct":"NCT06098833","url":"https://clinicaltrials.gov/study/NCT06098833","phase":"Phase 2","title":"Treatment of Neonatal Encephalopathy With Oral Sildenafil Suspension to Repair Brain Injury Secondary to Birth Asphyxia","status":"recruiting","sponsor":"Pia Wintermark","countries":["United States","Canada"],"us_states":["Colorado"]},{"nct":"NCT06324396","url":"https://clinicaltrials.gov/study/NCT06324396","phase":"Phase 1","title":"IMProving DRug Dosing and Outcomes for Single VEntricle Patients With Fontan Associated Liver Disease","status":"recruiting","sponsor":"Children's Mercy Hospital Kansas City","countries":["United States"],"us_states":["Missouri"]},{"nct":"NCT06875258","url":"https://clinicaltrials.gov/study/NCT06875258","phase":"Phase 4","title":"PEnile ReHABilitation After Nerve Sparing Robot-assisted Radical Prostatectomy for Prostate Cancer 2.0 (PEHAB-II)","status":"recruiting","sponsor":"The Netherlands Cancer Institute","countries":["Netherlands"],"us_states":[]},{"nct":"NCT06317805","url":"https://clinicaltrials.gov/study/NCT06317805","phase":"Phase 4","title":"Initial Triple Therapy Including Parenteral Treprostinil vs Initial Double Oral Therapy in PAH Group I Patients","status":"recruiting","sponsor":"AOP Orphan Pharmaceuticals AG","countries":["Austria","Czechia","France","Germany","Hungary","Italy","Poland","Portugal","Romania","Spain"],"us_states":[]},{"nct":"NCT05201144","url":"https://clinicaltrials.gov/study/NCT05201144","phase":"Phase 2","title":"A Trial of Phosphodiesterase-5 Inhibitor in Neonatal Congenital Diaphragmatic Hernia (TOP-CDH)","status":"recruiting","sponsor":"University of Utah","countries":["United States"],"us_states":["Utah"]},{"nct":"NCT05061368","url":"https://clinicaltrials.gov/study/NCT05061368","phase":"Phase 2","title":"Oral Sildenafil for Exercise Capacity, Dyspnea and Cardiopulmonary Function in COPD","status":"recruiting","sponsor":"University of Alberta","countries":["Canada"],"us_states":[]},{"nct":"NCT04797286","url":"https://clinicaltrials.gov/study/NCT04797286","phase":"Phase 2","title":"Sildenafil for Early Pulmonary Vascular Disease in Scleroderma","status":"recruiting","sponsor":"Johns Hopkins University","countries":["United States"],"us_states":["Louisiana","Maryland"]},{"nct":"NCT04898114","url":"https://clinicaltrials.gov/study/NCT04898114","phase":"Phase 1/Phase 2","title":"Nebulized Magnesium Sulfate and Sildenafil for Persistent Pulmonary Hypertension of Newborn","status":"recruiting","sponsor":"Sohag University","countries":["Egypt"],"us_states":[]},{"nct":"NCT07377084","url":"https://clinicaltrials.gov/study/NCT07377084","phase":"Not stated","title":"Metabolomics of Cancers of the Upper Aerodigestive Tract","status":"recruiting","sponsor":"Centre Antoine Lacassagne","countries":["France"],"us_states":[]},{"nct":"NCT01347216","url":"https://clinicaltrials.gov/study/NCT01347216","phase":"Not stated","title":"COMPERA / COMPERA-KIDS","status":"recruiting","sponsor":"Technische Universität Dresden","countries":["Belgium","Germany","Italy","Switzerland"],"us_states":[]}],"aliases":["Viagra","Revatio","sildenafil citrate"],"summary":"A prescription drug for erectile dysfunction, sold as Viagra, and for high blood pressure in the lungs, sold as Revatio.","citations":[{"n":1,"url":"https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/020895s049lbl.pdf","tier":"primary","type":"label","title":"Viagra (sildenafil citrate) tablets label, revised August 2017"},{"n":2,"url":"https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/021845Orig1s028,022473Orig1s019lbl.pdf","tier":"primary","type":"label","title":"Revatio (sildenafil) tablets, oral suspension and injection label, revised December 2024"},{"n":3,"url":"https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=020895","tier":"primary","type":"regulatory","title":"Drugs@FDA: Viagra (sildenafil citrate) tablets, application 020895"},{"n":4,"url":"https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=021845","tier":"primary","type":"regulatory","title":"Drugs@FDA: Revatio (sildenafil citrate) tablets, application 021845"},{"n":5,"url":"https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act","tier":"primary","type":"regulatory","title":"FDA: bulk drug substances used in compounding under section 503A"},{"n":6,"url":"https://www.fda.gov/media/94155/download","tier":"primary","type":"regulatory","title":"FDA: 503A bulk drug substances category list, updated May 2026"},{"n":7,"url":"https://www.fda.gov/drugs/medication-health-fraud-notifications/x10-natural-enhancement-supplement-may-be-harmful-due-hidden-drug-ingredients","tier":"primary","type":"regulatory","title":"FDA health fraud notice: sexual enhancement supplement with hidden sildenafil and tadalafil, 29 May 2026"},{"n":8,"url":"https://www.fda.gov/drugs/medication-health-fraud-notifications/magnum-brand-products-may-be-harmful-due-hidden-drug-ingredients","tier":"primary","type":"regulatory","title":"FDA health fraud notice: sexual enhancement products with hidden sildenafil, 2020 to 2026"},{"n":9,"url":"https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/duy-drugs-inc-542933-08282018","tier":"primary","type":"regulatory","title":"FDA warning letter on a product sold as a supplement with undeclared sildenafil, 28 August 2018"},{"n":10,"url":"https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/getfitmedical-llc-dba-getfitmedical-715801-09092025","tier":"primary","type":"regulatory","title":"FDA warning letter on claims that compounded sildenafil is a generic Viagra, 9 September 2025"},{"n":11,"url":"https://pubmed.ncbi.nlm.nih.gov/9580646/","tier":"peer-reviewed","type":"rct","title":"Randomized trial: oral sildenafil for erectile dysfunction, 1998"},{"n":12,"url":"https://pubmed.ncbi.nlm.nih.gov/16291984/","tier":"peer-reviewed","type":"rct","title":"Randomized trial: sildenafil for pulmonary arterial hypertension in adults, 2005"},{"n":13,"url":"https://pubmed.ncbi.nlm.nih.gov/22128226/","tier":"peer-reviewed","type":"rct","title":"Randomized dose-ranging trial: oral sildenafil in children with pulmonary arterial hypertension, 2012"},{"n":14,"url":"https://pubmed.ncbi.nlm.nih.gov/19884626/","tier":"peer-reviewed","type":"systematic-review","title":"Systematic review: PDE5 inhibitors and hormone treatments for erectile dysfunction, 2009"},{"n":15,"url":"https://pubmed.ncbi.nlm.nih.gov/25358826/","tier":"peer-reviewed","type":"human-trial","title":"Case-crossover study: sudden optic nerve damage (NAION) and PDE5 inhibitor use, 2015"},{"n":16,"url":"https://pubmed.ncbi.nlm.nih.gov/30646238/","tier":"peer-reviewed","type":"reference","title":"Study: unapproved drug ingredients in dietary supplements named in FDA warnings, 2007 to 2016"},{"n":17,"url":"https://pubmed.ncbi.nlm.nih.gov/35413880/","tier":"peer-reviewed","type":"animal","title":"Rat study: dapagliflozin and sildenafil in pulmonary arterial hypertension, 2022"},{"n":18,"url":"https://natlawreview.com/article/fdas-focus-returns-compounding-and-telehealth-another-wave-warning-letters","tier":"legal-analysis","type":"legal-analysis","title":"National Law Review: FDA's focus returns to compounding and telehealth"},{"n":19,"url":"https://www.cbsnews.com/news/many-dietary-supplements-contain-unapproved-dangerous-ingredients-study-finds/","tier":"established-news","type":"reference","title":"CBS News: many dietary supplements contain unapproved, dangerous ingredients, October 2018"},{"n":20,"url":"https://clinicaltrials.gov/study/NCT04797286","tier":"primary","type":"reference","title":"ClinicalTrials.gov NCT04797286: sildenafil for early pulmonary vascular disease in scleroderma"},{"n":21,"url":"https://clinicaltrials.gov/study/NCT05201144","tier":"primary","type":"reference","title":"ClinicalTrials.gov NCT05201144: sildenafil in newborns with congenital diaphragmatic hernia"}],"known_risks":["Taken with nitrate heart drugs, such as nitroglycerin, it can drop blood pressure to dangerous levels. Both labels say never to combine them [^1] [^2].","Both labels also say not to take it with riociguat, a drug for high blood pressure in the lungs [^1] [^2].","Sudden loss of sight in one or both eyes has been reported rarely. It can be a sign of damage to the nerve of the eye, called NAION [^1] [^15].","Sudden loss of hearing has been reported. The labels say to get medical care right away if it happens [^1] [^2].","An erection that lasts more than 4 hours needs emergency care [^1].","Taken with alpha-blockers or other blood pressure drugs, it can lower blood pressure too far [^1].","In a long study of children with high blood pressure in the lungs, more children died on higher doses. The Revatio label says the deaths came from the disease getting worse [^2] [^13].","In people whose lung disease comes from sickle cell disease, Revatio may cause serious pain crises [^2].","In the label's studies, the most common problems were headache, flushing and upset stomach [^1] [^11].","Products sold as supplements may hold hidden sildenafil. A person on nitrates may take it without knowing [^7] [^9]."],"short_answer":"Sildenafil is FDA-approved as Viagra for erectile dysfunction and as Revatio for high blood pressure in the lungs. For those uses the evidence grade is strong-human. Taken with nitrate heart drugs, it can drop blood pressure to dangerous levels. FDA keeps finding it hidden in sexual enhancement products.","evidence_grade":"strong-human","open_questions":["In the 2009 review, many trials were short and of low quality. Long-term benefits and harms are less clear [^14].","Nobody knows for sure if the drug itself causes NAION. The 2015 study was observational, so it shows a link, not proof of cause [^15].","The best dose for children is not settled. The 2012 trial called for more study of dosing by age and weight [^13].","It is not known if sildenafil helps people with scleroderma whose lung pressure is only a little high. A US trial is testing it [^20].","Nobody can say which products sold as supplements hide sildenafil. FDA says it cannot test every such product [^7]."],"section_routes":"The legal way to get sildenafil is a prescription [^1] [^2]. Viagra is approved for erectile dysfunction, and Revatio for high blood pressure in the lungs [^3] [^4].\n\nPharmacies may compound with a raw substance that meets a USP standard or is part of an FDA-approved drug [^5]. A compounded copy is not FDA-approved [^10].\n\nUS trials of sildenafil are open, such as one in people with scleroderma [^20] and one in newborns with a hole in the diaphragm, the muscle under the lungs [^21]. The trials block on this page lists open trials with their dates.","regulatory_as_of":"2026-10-26","section_channels":"Two ways of getting sildenafil other than an approved, prescribed product show up in FDA's records [^7] [^10]. The first is products sold as supplements for sexual enhancement with sildenafil hidden inside. FDA lab tests found it in such products in 2020, 2021 and 2026, and their labels did not list it [^7] [^8]. A 2018 study of FDA warnings found sildenafil was the most common hidden drug in these products [^16] [^19]. FDA warns the hidden drug can react with nitrates and drop blood pressure to dangerous levels [^7] [^8].\n\nThe second is websites that sell compounded sildenafil and call it a generic Viagra [^10] [^18]. FDA says a compounded copy is not FDA-approved, and that such claims are false or misleading [^10].","section_evidence":"The evidence grade is strong-human for its two approved uses [^11] [^12] [^14]. In a 1998 trial in men with erectile dysfunction, 69% of tries at sex succeeded on sildenafil [^11]. On a dummy pill, 22% did [^11]. A 2009 review of many trials found this class of drug helped erections more than a dummy pill [^14]. It found no clear difference between sildenafil, vardenafil and tadalafil [^14].\n\nIn a 2005 trial, 278 adults with high blood pressure in the lungs took sildenafil or a dummy pill for 12 weeks [^12]. Those on sildenafil walked about 45 to 50 meters farther in six minutes [^12]. In a 2012 trial of 235 children, the result for all doses together was only borderline [^13]. Medium and high doses did better than a dummy pill [^13].\n\nIn a 2022 study in rats with high blood pressure in the lungs, adding a diabetes drug did no better than sildenafil alone [^17].","regulatory_status":"fda-approved","section_what_it_is":"Sildenafil is a drug that blocks an enzyme called PDE5 [^1] [^2]. This relaxes the muscle in blood vessel walls [^2]. It is not a peptide.\n\nAs Viagra, it is a tablet for erectile dysfunction, which means trouble getting or keeping an erection [^1]. As Revatio, it treats high blood pressure in the arteries of the lungs, called pulmonary arterial hypertension [^2]. Revatio comes as a tablet, a liquid and a shot [^2]. FDA first approved sildenafil in 1998 [^1] [^3].","section_is_it_legal":"Sildenafil is FDA-approved: Drugs@FDA lists Viagra for erectile dysfunction and Revatio for high blood pressure in the lungs as approved prescription drugs [^3] [^4]. The approval is for use under a prescriber's care [^7]. It does not make a product sold as a supplement legal when that product hides sildenafil [^9]. Checked 26 October 2026.\n\nFDA says a product with undeclared sildenafil is a misbranded drug [^9]. FDA also says a compounded copy is not FDA-approved. In 2025, it warned that calling a compounded copy a generic Viagra is false or misleading [^10] [^18].\n\nPharmacies may compound with a raw substance that meets a USP standard or is part of an FDA-approved drug [^5]. Sildenafil is not on FDA's 503A category list [^6].","unofficial_channels":[{"type":"counterfeit-or-diverted","what_it_is":"Products sold as dietary supplements for sexual enhancement with sildenafil hidden inside and not listed on the label.","enforcement":[{"date":"2018-08-28","text":"FDA warning letter to a distributor whose product sold as a supplement held undeclared sildenafil.","source_url":"https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/duy-drugs-inc-542933-08282018"},{"date":"2026-05-29","text":"FDA told consumers not to buy or use a sexual enhancement supplement that its lab found to hold hidden sildenafil and tadalafil.","source_url":"https://www.fda.gov/drugs/medication-health-fraud-notifications/x10-natural-enhancement-supplement-may-be-harmful-due-hidden-drug-ingredients"},{"date":"2026-07-01","text":"FDA again told consumers not to buy or use a line of sexual enhancement products its lab found to hold hidden sildenafil and tadalafil.","source_url":"https://www.fda.gov/drugs/medication-health-fraud-notifications/magnum-brand-products-may-be-harmful-due-hidden-drug-ingredients"}],"legal_position":{"text":"FDA says a product with undeclared sildenafil is a misbranded drug, because its label hides the drug and gives no warnings.","source_url":"https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/duy-drugs-inc-542933-08282018"},"documented_risks":[{"text":"FDA warns the hidden drug can react with nitrates, such as nitroglycerin, and lower blood pressure to dangerous levels.","source_url":"https://www.fda.gov/drugs/medication-health-fraud-notifications/x10-natural-enhancement-supplement-may-be-harmful-due-hidden-drug-ingredients"},{"text":"FDA says it cannot test every product sold as a supplement for hidden drugs.","source_url":"https://www.fda.gov/drugs/medication-health-fraud-notifications/x10-natural-enhancement-supplement-may-be-harmful-due-hidden-drug-ingredients"},{"text":"From 2007 to 2016, sildenafil was the most common hidden drug in sexual enhancement supplements named in FDA warnings.","source_url":"https://pubmed.ncbi.nlm.nih.gov/30646238/"}]},{"type":"telehealth","what_it_is":"Websites that sell compounded sildenafil to consumers and call it a generic Viagra.","enforcement":[{"date":"2025-09-09","text":"FDA warning letter to a website that sold compounded sildenafil and called it a generic Viagra.","source_url":"https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/getfitmedical-llc-dba-getfitmedical-715801-09092025"}],"legal_position":{"text":"FDA says a compounded drug is not FDA-approved, and a claim that it is the same as an approved drug is false or misleading.","source_url":"https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/getfitmedical-llc-dba-getfitmedical-715801-09092025"},"documented_risks":[{"text":"FDA says such claims imply the copy is the same as the approved drug when it is 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