Non-peptide
Tadalafil
Tadalafil is FDA-approved as Cialis for erectile dysfunction and an enlarged prostate, and as Adcirca for high blood pressure in the lungs. For those uses the evidence grade is strong-human. With nitrate heart drugs, it can drop blood pressure dangerously. FDA keeps finding it hidden in products sold as supplements.
This page has not been individually reviewed by a clinician.
Fact sheet · 6 facts
every row cites its source and its date| Fact | Value | Tier | Checked | Source |
|---|---|---|---|---|
| Also called | Cialis, Adcirca | primary | accessdata.fda.gov | |
| Class | non-peptide | primary | accessdata.fda.gov | |
| Regulatory status | fda-approved | primary | accessdata.fda.gov | |
| Status source read | 2026-10-26 | primary | accessdata.fda.gov | |
| Evidence grade | strong-human | our assessment | peptideindex.ai | |
| Label dosing | From the Cialis and Adcirca labels. For erectile dysfunction as needed, most men start with 10 mg before sex, no more than once a day. The dose may go up to 20 mg or down to 5 mg. For erectile dysfunction once a day, the start is 2.5 mg daily, which may go up to 5 mg. For an enlarged prostate, with or without erectile dysfunction, the dose is 5 mg once a day at about the same time. For high blood pressure in the lungs, the dose is 40 mg, two 20 mg tablets, once a day. Kidney or liver disease and some other drugs call for lower doses. The prescriber sets the dose. | primary | accessdata.fda.gov |
Short answer
Tadalafil is FDA-approved as Cialis for erectile dysfunction and an enlarged prostate, and as Adcirca for high blood pressure in the lungs. For those uses the evidence grade is strong-human. With nitrate heart drugs, it can drop blood pressure dangerously. FDA keeps finding it hidden in products sold as supplements.
Our assessment, drawn from the sources below.
What it is
Tadalafil is a drug that blocks an enzyme called PDE5 [1] [2]. It is not a peptide.
As Cialis, it is a tablet for erectile dysfunction, which means trouble getting or keeping an erection [1]. Cialis also treats the urinary symptoms of an enlarged prostate, called benign prostatic hyperplasia [1]. As Adcirca, it treats high blood pressure in the arteries of the lungs, called pulmonary arterial hypertension [2]. The Cialis label says it can help erections for up to 36 hours after a dose [1]. FDA first approved tadalafil as Cialis in 2003 [3] [9].
Where it stands legally
Tadalafil is FDA-approved: Drugs@FDA lists Cialis and Adcirca as approved prescription drugs [3] [4]. The approval is for use under a prescriber's care [9]. It does not make a product sold as a supplement legal when that product hides tadalafil [9]. Checked 26 October 2026.
FDA says a product with tadalafil cannot be a dietary supplement, because Cialis was approved first [9]. It says a product with undeclared tadalafil 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 Cialis is false or misleading [10] [19].
Pharmacies may compound with a raw substance that meets a USP standard or is part of an FDA-approved drug [5]. Tadalafil is not on FDA's 503A category list [6].
What the evidence shows
Evidence grade: strong-human · our assessment
The evidence grade is strong-human for its three approved uses [11] [12] [14]. In a 2003 trial, 348 men with erectile dysfunction took tadalafil or a dummy pill [11]. Tried 36 hours after a dose, 59.2% of tries at sex succeeded on tadalafil [11]. On the dummy pill, 28.3% did [11]. A 2017 review of 16 trials found tadalafil and sildenafil gave similar results [15].
In a 2008 trial, 1,058 men with an enlarged prostate took tadalafil or a dummy pill for 12 weeks [14]. Urinary symptom scores improved more on tadalafil [14]. The peak flow of urine did not change [14].
In a 2009 trial, 405 adults with high blood pressure in the lungs took tadalafil or a dummy pill for 16 weeks [12]. Overall, people on tadalafil walked about 33 meters farther in six minutes [12]. Only the highest dose met the study's bar for a clear result [12]. In a 2015 trial of 500 adults, starting it with a second drug, ambrisentan, cut the risk of getting worse by about half [13].
In a 2012 study in rats with high blood pressure in the lungs, adding a cholesterol drug did better than tadalafil alone [18].
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].
- In an emergency, the labels say at least 48 hours should pass after the last dose before a nitrate is given [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. It can be a sign of damage to the nerve of the eye, called NAION [1] [2] [16].
- Sudden loss of hearing has been reported. The labels say to stop it and get medical care right away [1] [2].
- An erection that lasts more than 4 hours needs emergency care [1] [2].
- Taken with alpha-blockers, other blood pressure drugs or a lot of alcohol, it can lower blood pressure too far [1].
- Men whose heart is too weak for sex should not use it for erectile dysfunction [1].
- The Adcirca label says it is not recommended for people with a rare blockage of the small veins in the lungs [2].
- Some people have had serious allergic reactions, including a severe skin rash [2].
- In the label's studies, the most common problems were headache, upset stomach, back pain, muscle aches and flushing [1] [11].
- Products sold as supplements may hold hidden tadalafil. A person on nitrates may take it without knowing [7] [9].
What nobody knows yet
- Some men with an enlarged prostate start it with finasteride. The label says nobody knows if it adds benefit after 26 weeks [1].
- Nobody knows for sure if the drug itself causes NAION. The 2015 study was observational, so it shows a link, not proof of cause [16].
- Its use in children has not been established. A trial in boys with Duchenne muscular dystrophy found no benefit [1].
- It is not known if tadalafil eases shortness of breath in people with COPD and high lung pressure. A US trial in veterans is testing it [21].
- A 2012 rat study found tadalafil plus a cholesterol drug lowered lung pressure more than either alone. Nobody has shown this in people [18].
- Nobody can say which products sold as supplements hide tadalafil. FDA says it cannot test every such product [7].
Legitimate ways to get it
The legal way to get tadalafil is a prescription [1] [2]. Cialis is approved for erectile dysfunction and an enlarged prostate. Adcirca is approved for high blood pressure in the lungs [3] [4].
Pharmacies 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].
Trials of tadalafil are open, such as a US trial in veterans with COPD and high lung pressure [21]. Another is for people who have had a Fontan palliation [22]. The trials block on this page lists open trials with their dates.
Approved product
Approved by FDA as a prescription tablet for erectile dysfunction and an enlarged prostate.
Brand names: Cialis
Manufacturer: Eli Lilly
Indication: Treatment of erectile dysfunction, the signs and symptoms of benign prostatic hyperplasia, or both.
Approved product
Approved by FDA as a prescription tablet for high blood pressure in the lungs.
Brand names: Adcirca
Manufacturer: Eli Lilly
Indication: Treatment of pulmonary arterial hypertension (WHO Group 1) to improve exercise ability.
Lawful compounding
Pharmacies may compound with a raw substance that meets a USP standard or is part of an FDA-approved drug.
Recruiting trials
A listing is not a recommendation. Trials have strict eligibility rules. Talk to your doctor and read the official record.
Snapshot of .clinicaltrials.gov
NCT07890285
A Study of Opsynvi in Adults Participants With Pulmonary Arterial Hypertension in Korea
Phase: Not stated · Sponsor: Janssen Korea, Ltd., Korea · Status: Not yet recruiting
Countries: none listed
US states: none listed
NCT07882901
Effects of Tadalafil on Cognition and Cerebral Hemodynamics in Elderly Patients With Mild Cognitive Impairment
Phase: Phase 2 · Sponsor: Los Angeles Brain Science Project · Status: Not yet recruiting
Countries: United States
US states: California
NCT07537855
Efficacy of Intracavernosal Xeomin With Tadalafil for Mild-Moderate Erectile Dysfunction
Phase: Phase 2 · Sponsor: Northwestern University · Status: Not yet recruiting
Countries: none listed
US states: none listed
NCT07576335
Multimodal Prehabilitation and Rehabilitation for Men Undergoing Robot-Assisted Radical Prostatectomy
Phase: Phase 2 · Sponsor: Surgical Outcomes Research Centre (SOuRCe) · Status: Recruiting
Countries: Australia
US states: none listed
NCT07773103
Endothelial Markers and Tadalafil Response
Phase: Not stated · Sponsor: Al-Azhar University · Status: Recruiting
Countries: Egypt
US states: none listed
NCT07753720
Daily Tadalafil as Adjunctive Therapy Versus Monotherapy for PDE5 Inhibitor-Resistant Erectile Dysfunction
Phase: Phase 4 · Sponsor: Al-Azhar University · Status: Recruiting
Countries: Egypt
US states: none listed
NCT07707505
Intracavernosal Exosomes vs. Rectal Ozone for Post-RARP Erectile Dysfunction
Phase: Not applicable · Sponsor: Medipol University · Status: Not yet recruiting
Countries: Turkey (Türkiye)
US states: none listed
NCT07722884
Tamsulosin Monotherapy Versus Combination Therapy With Tadalafil (2.5 mg vs 5 mg) in Managing Male LUTS Secondary to BPH
Phase: Not applicable · Sponsor: Ain Shams University · Status: Recruiting
Countries: Egypt
US states: none listed
NCT07642505
L-Citrulline and Tadalafil for Mild to Moderate Erectile Dysfunction
Phase: Phase 4 · Sponsor: Beni-Suef University · Status: Recruiting
Countries: Egypt
US states: none listed
NCT07654413
Tamsulosin With or Without Tadalafil for Trial Without Catheter After Acute Urinary Retention Due to Benign Prostatic Hyperplasia
Phase: Phase 4 · Sponsor: Beni-Suef University · Status: Recruiting
Countries: Egypt
US states: none listed
NCT07245680
COMMODITIES Trial: Initial Dual Oral Therapy vs Monotherapy in PAH With Cardiovascular Comorbidities
Phase: Phase 3 · Sponsor: Assistance Publique - Hôpitaux de Paris · Status: Recruiting
Countries: France
US states: none listed
NCT07466030
Tadalafil 5 mg on Storage Lower Urinary Tract Symptoms After Anatomical Endoscopic Enucleation of the Prostate
Phase: Phase 1 · Sponsor: Assiut University · Status: Not yet recruiting
Countries: none listed
US states: none listed
NCT07117383
Hezkue®, Hezkue Turbo®, and Commercial Sildenafil Products in Fed Healthy Male Subject
Phase: Phase 1 · Sponsor: Aspargo Labs, Inc · Status: Not yet recruiting
Countries: United States
US states: New York
NCT07231185
Phase 2 Efficacy Study of Sildenafil Products in Adult Men With Erectile Dysfunction
Phase: Phase 2 · Sponsor: Aspargo Labs, Inc · Status: Not yet recruiting
Countries: none listed
US states: none listed
NCT07562282
Safety and Efficacy of Combination of Tamsulosin 0.4 mg Plus Tadalafil 5mg Versus 2.5 mg
Phase: Not applicable · Sponsor: Ain Shams University · Status: Recruiting
Countries: Egypt
US states: none listed
NCT07391579
Daily Tadalafil 5 mg Combined With On-Demand Sildenafil 100 mg for Treatment of Erectile Dysfunction in PDE-5I Non Responder Patients
Phase: Phase 4 · Sponsor: Mansoura University · Status: Recruiting
Countries: Egypt
US states: none listed
NCT07177326
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
Phase: Phase 3 · Sponsor: Assiut University · Status: Not yet recruiting
Countries: none listed
US states: none listed
NCT07172815
PDE5 Inhibitor for Alzheimer's Disease
Phase: Phase 2 · Sponsor: Imperial College London · Status: Not yet recruiting
Countries: none listed
US states: none listed
NCT07416968
Randomized Controlled Trial Comparing Low Dose Tadalafil Versus Solifenacin For Management of Overactive Bladder in Women: Multicenter Egyptian National Study
Phase: Phase 4 · Sponsor: Mansoura University · Status: Recruiting
Countries: Egypt
US states: none listed
NCT06968962
Comparison of Sequential to Initial Combination Therapy in PAH
Phase: Not applicable · Sponsor: Second Affiliated Hospital, Zhejiang University, School of Medicine · Status: Recruiting
Countries: China
US states: none listed
NCT06962462
Daily Tadalafil in Diabetic ED Patients
Phase: Not applicable · Sponsor: South Valley University · Status: Not yet recruiting
Countries: none listed
US states: none listed
NCT06753981
Efficacy and Safety of Triple-targeted Drug Therapy in Treatment-naive Patients With Non-low-risk PAH: A Real-world, Multicenter Study
Phase: Not stated · Sponsor: Qianfoshan Hospital · Status: Recruiting
Countries: China
US states: none listed
NCT06583590
Evaluation of Efficacy of Botulinum Toxin A Plus Oral Tadalafil 5 mg in Diabetic Men With Erectile Dysfunction
Phase: Phase 2/Phase 3 · Sponsor: Aswan University Hospital · Status: Recruiting
Countries: Egypt
US states: none listed
NCT06290713
Vasodilator and Exercise Study for DMD (VASO-REx)
Phase: Phase 2 · Sponsor: University of Florida · Status: Recruiting
Countries: United States
US states: Florida
NCT05937854
Breathe Easier With Tadalafil Therapy for Dyspnea in COPD-PH
Phase: Phase 2 · Sponsor: VA Office of Research and Development · Status: Recruiting
Countries: United States
US states: Colorado, Georgia, Massachusetts, Nebraska, Rhode Island
NCT05844462
Tadalafil for Severe Pulmonary Hypertension Due to Chronic Obstructive Pulmonary Disease
Phase: Phase 3 · Sponsor: Assistance Publique - Hôpitaux de Paris · Status: Recruiting
Countries: France
US states: none listed
NCT06317805
Initial Triple Therapy Including Parenteral Treprostinil vs Initial Double Oral Therapy in PAH Group I Patients
Phase: Phase 4 · Sponsor: AOP Orphan Pharmaceuticals AG · Status: Recruiting
Countries: Austria, Czechia, France, Germany, Hungary, Italy, Poland, Portugal, Romania, Spain
US states: none listed
NCT05558007
Safety and Efficacy Evaluation of BZ371A Topically Applied on Prostatectomized Patients
Phase: Phase 2 · Sponsor: Biozeus Biopharmaceutical S.A. · Status: Recruiting
Countries: Brazil
US states: none listed
NCT07499804
Effect of Tadalafil on Endometrial Thickness and Frozen Embryo Transfer Outcomes
Phase: Phase 4 · Sponsor: Beni-Suef University · Status: Recruiting
Countries: Egypt
US states: none listed
NCT06717711
Low-Intensity Extracorporeal Shockwave Therapy on Penile Rehabilitation After Robot-assisted Surgical Treatment of Genitourinary Cancers
Phase: Phase 3 · Sponsor: Regina Elena Cancer Institute · Status: Recruiting
Countries: Italy
US states: none listed
NCT05955001
Efficacy of Tadalafil (5mg) For Treatment of Early Storage Symptoms and Erectile Dysfunction After Endoscopic Enucleation of Prostate
Phase: Phase 2/Phase 3 · Sponsor: Mansoura University · Status: Recruiting
Countries: Egypt
US states: none listed
NCT05206955
Study of Tadalafil vs. Placebo for Improving Hemodynamics and End-Organ Dysfunction in Fontan Physiology
Phase: Phase 3 · Sponsor: Mayo Clinic · Status: Recruiting
Countries: United States
US states: Minnesota
NCT05179876
A Study Providing Treatment Access in Participants With Pulmonary Hypertension Completing a Parent Study and Having no Other Option
Phase: Phase 3 · Sponsor: Actelion · Status: Recruiting
Countries: Belarus, Belgium, Bulgaria, China, Hungary, Poland, Russia, South Africa, South Korea, Taiwan, Thailand, Ukraine, Vietnam
US states: none listed
NCT05051436
The Effects of Mirabegron and Tadalafil on Glucose Tolerance in Prediabetics
Phase: Phase 4 · Sponsor: Philip Kern · Status: Recruiting
Countries: United States
US states: Kentucky
How people are getting it anyway
This section describes what happens and is not a recommendation.
Two ways of getting tadalafil other than an approved, prescribed product show up in FDA's records [7] [10]. The first is products sold as supplements or foods with tadalafil hidden inside. FDA lab tests found it in such products, including honey-based products, and their labels did not list it [7] [8] [9] [20]. FDA first found it in one such product in 2019, and found it there again in 2025 and 2026 [7]. A 2018 study of FDA warnings found hidden drugs were common in sexual enhancement supplements [17]. FDA warns the hidden drug can react with nitrates and drop blood pressure to dangerous levels [7] [8].
The second is websites that sell compounded tadalafil and call it a generic Cialis [10] [19]. FDA says a compounded copy is not FDA-approved, and that such claims are false or misleading [10].
Counterfeit or diverted
Products sold as dietary supplements or foods for sexual enhancement with tadalafil hidden inside and not listed on the label.
The lawFDA says a product with tadalafil cannot be a dietary supplement, and one with undeclared tadalafil is a misbranded drug.fda.gov
Documented riskFDA warns the hidden drug may react with nitrates, such as nitroglycerin, and lower blood pressure to dangerous levels.fda.gov
Documented riskFDA says it cannot test every product sold as a supplement for hidden drugs.fda.gov
Documented riskFDA lab tests found tadalafil, not listed on the label, in honey-based products sold for sexual enhancement.fda.gov
Enforcement FDA told consumers not to buy or use a sexual enhancement product its lab found to hold tadalafil.fda.gov
Enforcement FDA warning letter to an online retailer that shipped products sold as supplements or food with undeclared tadalafil or sildenafil.fda.gov
Enforcement FDA said new samples of the same product again held tadalafil not listed on the label.fda.gov
Telehealth
Websites that sell compounded tadalafil to consumers and call it a generic Cialis.
The lawFDA says a compounded drug is not FDA-approved, and a claim that it is the same as an approved drug is false or misleading.fda.gov
Documented riskFDA says such claims imply the copy is the same as the approved drug when it is not.fda.gov
Enforcement FDA warning letter to a website that sold compounded tadalafil and called it a generic Cialis.fda.gov
Sources
- [1]Cialis (tadalafil) tablets label, revised February 2018Label · primary
- [2]Adcirca (tadalafil) tablets label, revised September 2020Label · primary
- [3]Drugs@FDA: Cialis (tadalafil) tablets, application 021368Regulatory · primary
- [4]Drugs@FDA: Adcirca (tadalafil) tablets, application 022332Regulatory · primary
- [5]FDA: bulk drug substances used in compounding under section 503ARegulatory · primary
- [6]FDA: 503A bulk drug substances category list, updated May 2026Regulatory · primary
- [7]FDA public notification: sexual enhancement product with hidden tadalafil, 2019 to 2026Regulatory · primary
- [8]FDA: tainted honey-based products with hidden drug ingredientsRegulatory · primary
- [9]FDA warning letter on products sold as supplements or food with undeclared tadalafil, 20 December 2023Regulatory · primary
- [10]FDA warning letter on claims that compounded tadalafil is a generic Cialis, 9 September 2025Regulatory · primary
- [11]Randomized trial: tadalafil for erectile dysfunction at 24 and 36 hours, 2003Rct · peer-reviewed
- [12]Randomized trial: tadalafil for pulmonary arterial hypertension, 2009Rct · peer-reviewed
- [13]Randomized trial: starting ambrisentan plus tadalafil in pulmonary arterial hypertension, 2015Rct · peer-reviewed
- [14]Randomized dose-finding trial: once daily tadalafil for benign prostatic hyperplasia, 2008Rct · peer-reviewed
- [15]Systematic review: tadalafil compared with sildenafil for erectile dysfunction, 2017Systematic review · peer-reviewed
- [16]Case-crossover study: sudden optic nerve damage (NAION) and PDE5 inhibitor use, 2015Human trial · peer-reviewed
- [17]Study: unapproved drug ingredients in dietary supplements named in FDA warnings, 2007 to 2016Reference · peer-reviewed
- [18]Rat study: tadalafil and simvastatin in pulmonary hypertension, 2012Animal · peer-reviewed
- [19]National Law Review: FDA's focus returns to compounding and telehealthLegal analysis · legal-analysis
- [20]NBC News: honey-based sexual supplements may contain Cialis and Viagra ingredients, July 2022Reference · established-news
- [21]ClinicalTrials.gov NCT05937854: tadalafil for shortness of breath in COPD with high lung pressureReference · primary
- [22]ClinicalTrials.gov NCT05206955: tadalafil compared with placebo in Fontan physiologyReference · primary
Last verified · 6 facts · 8 sources
- clinicaltrials.gov
- clinicaltrials.gov
- peptideindex.ai
- peptideindex.ai
- pubmed.ncbi.nlm.nih.gov
- accessdata.fda.gov
- accessdata.fda.gov
- fda.gov
Primary source: https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=021368
Machine readers: JSON · Markdown · Status history: Change log
Information, not medical advice.
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