# 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.

Status checked: 2026-10-26. Last verified: 2026-10-26. Primary source: https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=021368

This page has not been individually reviewed by a clinician.

Information, not medical advice.

| Fact | Value | Tier | Checked | Source |
|---|---|---|---|---|
| Also called | Cialis, Adcirca | primary | 2026-10-26 | [source](https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/021368s030lbl.pdf) |
| Class | non-peptide | primary | 2026-10-26 | [source](https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/021368s030lbl.pdf) |
| Regulatory status | fda-approved | primary | 2026-10-26 | [source](https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=021368) |
| Status source read | 2026-10-26 | primary | 2026-10-26 | [source](https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=021368) |
| Evidence grade | strong-human | our assessment | 2026-10-26 | [source](https://peptideindex.ai/methodology#evidence-grade) |
| 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 | 2026-10-26 | [source](https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/021368s030lbl.pdf) |

## Name

Tadalafil

Source: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/021368s030lbl.pdf

## Summary

A prescription drug for erectile dysfunction and an enlarged prostate, sold as Cialis, and for high blood pressure in the lungs, sold as Adcirca.

Source: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/021368s030lbl.pdf

## 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.

Source: https://peptideindex.ai/methodology#short-answer

## 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].

Source: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/021368s030lbl.pdf

## 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].

Source: https://www.fda.gov/drugs/medication-health-fraud/public-notification-green-lumber-contains-hidden-drug-ingredient

## 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].

Source: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/021368s030lbl.pdf

## 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].

Source: https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=021368

## What the evidence shows

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].

Source: https://pubmed.ncbi.nlm.nih.gov/19470885/

## 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.

Source: https://clinicaltrials.gov/study/NCT05206955

## 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].

Source: https://www.fda.gov/drugs/medication-health-fraud/public-notification-green-lumber-contains-hidden-drug-ingredient

## Access routes

Source: https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=021368

### Approved product

Detail: 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.

Source: https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=021368

### Approved product

Detail: 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.

Source: https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=022332

### Lawful compounding

Detail: Pharmacies may compound with a raw substance that meets a USP standard or is part of an FDA-approved drug.

Source: https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act

## Unofficial channels

Source: https://www.fda.gov/drugs/medication-health-fraud/public-notification-green-lumber-contains-hidden-drug-ingredient

### Counterfeit or diverted

What it is: Products sold as dietary supplements or foods for sexual enhancement with tadalafil hidden inside and not listed on the label.

Legal position: FDA says a product with tadalafil cannot be a dietary supplement, and one with undeclared tadalafil is a misbranded drug. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/amazoncom-inc-662503-12202023)

Documented risks:

- FDA warns the hidden drug may react with nitrates, such as nitroglycerin, and lower blood pressure to dangerous levels. (source: https://www.fda.gov/drugs/medication-health-fraud/public-notification-green-lumber-contains-hidden-drug-ingredient)
- FDA says it cannot test every product sold as a supplement for hidden drugs. (source: https://www.fda.gov/drugs/medication-health-fraud/public-notification-green-lumber-contains-hidden-drug-ingredient)
- FDA lab tests found tadalafil, not listed on the label, in honey-based products sold for sexual enhancement. (source: https://www.fda.gov/consumers/health-fraud-scams/tainted-honey-based-products-hidden-active-drug-ingredients)

Enforcement:

- 2019-09-19: FDA told consumers not to buy or use a sexual enhancement product its lab found to hold tadalafil. (source: https://www.fda.gov/drugs/medication-health-fraud/public-notification-green-lumber-contains-hidden-drug-ingredient)
- 2023-12-20: FDA warning letter to an online retailer that shipped products sold as supplements or food with undeclared tadalafil or sildenafil. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/amazoncom-inc-662503-12202023)
- 2026-10-23: FDA said new samples of the same product again held tadalafil not listed on the label. (source: https://www.fda.gov/drugs/medication-health-fraud/public-notification-green-lumber-contains-hidden-drug-ingredient)

Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/amazoncom-inc-662503-12202023

### Telehealth

What it is: Websites that sell compounded tadalafil to consumers and call it a generic Cialis.

Legal position: 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: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/getfitmedical-llc-dba-getfitmedical-715801-09092025)

Documented risks:

- FDA says such claims imply the copy is the same as the approved drug when it is not. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/getfitmedical-llc-dba-getfitmedical-715801-09092025)

Enforcement:

- 2025-09-09: FDA warning letter to a website that sold compounded tadalafil and called it a generic Cialis. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/getfitmedical-llc-dba-getfitmedical-715801-09092025)

Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/getfitmedical-llc-dba-getfitmedical-715801-09092025

## Recruiting trials

Snapshot date: 2026-10-26.

A listing is not a recommendation. Trials have strict eligibility rules. Talk to your doctor and read the official record.

- nct NCT07890285, url https://clinicaltrials.gov/study/NCT07890285, phase Not stated, title A Study of Opsynvi in Adults Participants With Pulmonary Arterial Hypertension in Korea, status not-yet-recruiting, sponsor Janssen Korea, Ltd., Korea, countries none listed, us states none listed
- nct NCT07882901, url https://clinicaltrials.gov/study/NCT07882901, phase Phase 2, title Effects of Tadalafil on Cognition and Cerebral Hemodynamics in Elderly Patients With Mild Cognitive Impairment, status not-yet-recruiting, sponsor Los Angeles Brain Science Project, countries United States, us states California
- nct NCT07537855, url https://clinicaltrials.gov/study/NCT07537855, phase Phase 2, title Efficacy of Intracavernosal Xeomin With Tadalafil for Mild-Moderate Erectile Dysfunction, status not-yet-recruiting, sponsor Northwestern University, countries none listed, us states none listed
- nct NCT07576335, url https://clinicaltrials.gov/study/NCT07576335, phase Phase 2, title Multimodal Prehabilitation and Rehabilitation for Men Undergoing Robot-Assisted Radical Prostatectomy, status recruiting, sponsor Surgical Outcomes Research Centre (SOuRCe), countries Australia, us states none listed
- nct NCT07773103, url https://clinicaltrials.gov/study/NCT07773103, phase Not stated, title Endothelial Markers and Tadalafil Response, status recruiting, sponsor Al-Azhar University, countries Egypt, us states none listed
- nct NCT07753720, url https://clinicaltrials.gov/study/NCT07753720, phase Phase 4, title Daily Tadalafil as Adjunctive Therapy Versus Monotherapy for PDE5 Inhibitor-Resistant Erectile Dysfunction, status recruiting, sponsor Al-Azhar University, countries Egypt, us states none listed
- nct NCT07707505, url https://clinicaltrials.gov/study/NCT07707505, phase Not applicable, title Intracavernosal Exosomes vs. Rectal Ozone for Post-RARP Erectile Dysfunction, status not-yet-recruiting, sponsor Medipol University, countries Turkey (Türkiye), us states none listed
- nct NCT07722884, url https://clinicaltrials.gov/study/NCT07722884, phase Not applicable, title Tamsulosin Monotherapy Versus Combination Therapy With Tadalafil (2.5 mg vs 5 mg) in Managing Male LUTS Secondary to BPH, status recruiting, sponsor Ain Shams University, countries Egypt, us states none listed
- nct NCT07642505, url https://clinicaltrials.gov/study/NCT07642505, phase Phase 4, title L-Citrulline and Tadalafil for Mild to Moderate Erectile Dysfunction, status recruiting, sponsor Beni-Suef University, countries Egypt, us states none listed
- nct NCT07654413, url https://clinicaltrials.gov/study/NCT07654413, phase Phase 4, title Tamsulosin With or Without Tadalafil for Trial Without Catheter After Acute Urinary Retention Due to Benign Prostatic Hyperplasia, status recruiting, sponsor Beni-Suef University, countries Egypt, us states none listed
- nct NCT07245680, url https://clinicaltrials.gov/study/NCT07245680, phase Phase 3, title COMMODITIES Trial: Initial Dual Oral Therapy vs Monotherapy in PAH With Cardiovascular Comorbidities, status recruiting, sponsor Assistance Publique - Hôpitaux de Paris, countries France, us states none listed
- nct NCT07466030, url https://clinicaltrials.gov/study/NCT07466030, phase Phase 1, title Tadalafil 5 mg on Storage Lower Urinary Tract Symptoms After Anatomical Endoscopic Enucleation of the Prostate, status not-yet-recruiting, sponsor Assiut University, countries none listed, us states none listed
- 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 none listed, us states none listed
- nct NCT07562282, url https://clinicaltrials.gov/study/NCT07562282, phase Not applicable, title Safety and Efficacy of Combination of Tamsulosin 0.4 mg Plus Tadalafil 5mg Versus 2.5 mg, status recruiting, sponsor Ain Shams University, countries Egypt, us states none listed
- 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 none listed
- 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 none listed, us states none listed
- nct NCT07172815, url https://clinicaltrials.gov/study/NCT07172815, phase Phase 2, title PDE5 Inhibitor for Alzheimer's Disease, status not-yet-recruiting, sponsor Imperial College London, countries none listed, us states none listed
- nct NCT07416968, url https://clinicaltrials.gov/study/NCT07416968, phase Phase 4, title Randomized Controlled Trial Comparing Low Dose Tadalafil Versus Solifenacin For Management of Overactive Bladder in Women: Multicenter Egyptian National Study, status recruiting, sponsor Mansoura University, countries Egypt, us states none listed
- nct NCT06968962, url https://clinicaltrials.gov/study/NCT06968962, phase Not applicable, title Comparison of Sequential to Initial Combination Therapy in PAH, status recruiting, sponsor Second Affiliated Hospital, Zhejiang University, School of Medicine, countries China, us states none listed
- nct NCT06962462, url https://clinicaltrials.gov/study/NCT06962462, phase Not applicable, title Daily Tadalafil in Diabetic ED Patients, status not-yet-recruiting, sponsor South Valley University, countries none listed, us states none listed
- 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 none listed
- nct NCT06583590, url https://clinicaltrials.gov/study/NCT06583590, phase Phase 2/Phase 3, title Evaluation of Efficacy of Botulinum Toxin A Plus Oral Tadalafil 5 mg in Diabetic Men With Erectile Dysfunction, status recruiting, sponsor Aswan University Hospital, countries Egypt, us states none listed
- nct NCT06290713, url https://clinicaltrials.gov/study/NCT06290713, phase Phase 2, title Vasodilator and Exercise Study for DMD (VASO-REx), status recruiting, sponsor University of Florida, countries United States, us states Florida
- nct NCT05937854, url https://clinicaltrials.gov/study/NCT05937854, phase Phase 2, title Breathe Easier With Tadalafil Therapy for Dyspnea in COPD-PH, status recruiting, sponsor VA Office of Research and Development, countries United States, us states Colorado, Georgia, Massachusetts, Nebraska, Rhode Island
- nct NCT05844462, url https://clinicaltrials.gov/study/NCT05844462, phase Phase 3, title Tadalafil for Severe Pulmonary Hypertension Due to Chronic Obstructive Pulmonary Disease, status recruiting, sponsor Assistance Publique - Hôpitaux de Paris, countries France, us states none listed
- 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 none listed
- nct NCT05558007, url https://clinicaltrials.gov/study/NCT05558007, phase Phase 2, title Safety and Efficacy Evaluation of BZ371A Topically Applied on Prostatectomized Patients, status recruiting, sponsor Biozeus Biopharmaceutical S.A., countries Brazil, us states none listed
- nct NCT07499804, url https://clinicaltrials.gov/study/NCT07499804, phase Phase 4, title Effect of Tadalafil on Endometrial Thickness and Frozen Embryo Transfer Outcomes, status recruiting, sponsor Beni-Suef University, countries Egypt, us states none listed
- nct NCT06717711, url https://clinicaltrials.gov/study/NCT06717711, phase Phase 3, title Low-Intensity Extracorporeal Shockwave Therapy on Penile Rehabilitation After Robot-assisted Surgical Treatment of Genitourinary Cancers, status recruiting, sponsor Regina Elena Cancer Institute, countries Italy, us states none listed
- nct NCT05955001, url https://clinicaltrials.gov/study/NCT05955001, phase Phase 2/Phase 3, title Efficacy of Tadalafil (5mg) For Treatment of Early Storage Symptoms and Erectile Dysfunction After Endoscopic Enucleation of Prostate, status recruiting, sponsor Mansoura University, countries Egypt, us states none listed
- nct NCT05206955, url https://clinicaltrials.gov/study/NCT05206955, phase Phase 3, title Study of Tadalafil vs. Placebo for Improving Hemodynamics and End-Organ Dysfunction in Fontan Physiology, status recruiting, sponsor Mayo Clinic, countries United States, us states Minnesota
- nct NCT05179876, url https://clinicaltrials.gov/study/NCT05179876, phase Phase 3, title A Study Providing Treatment Access in Participants With Pulmonary Hypertension Completing a Parent Study and Having no Other Option, status recruiting, sponsor Actelion, countries Belarus, Belgium, Bulgaria, China, Hungary, Poland, Russia, South Africa, South Korea, Taiwan, Thailand, Ukraine, Vietnam, us states none listed
- nct NCT05051436, url https://clinicaltrials.gov/study/NCT05051436, phase Phase 4, title The Effects of Mirabegron and Tadalafil on Glucose Tolerance in Prediabetics, status recruiting, sponsor Philip Kern, countries United States, us states Kentucky

Source: https://clinicaltrials.gov/api/v2/studies?query.intr=tadalafil&filter.overallStatus=RECRUITING%2CNOT_YET_RECRUITING&pageSize=50&sort=StartDate%3Adesc&countTotal=true&fields=NCTId%2CBriefTitle%2COverallStatus%2CPhase%2CLeadSponsorName%2CStartDate%2CLocationCountry%2CLocationState

## Sources

Source: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/021368s030lbl.pdf

### 1. Cialis (tadalafil) tablets label, revised February 2018

Type: label

Tier: primary

Source: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/021368s030lbl.pdf

### 2. Adcirca (tadalafil) tablets label, revised September 2020

Type: label

Tier: primary

Source: https://www.accessdata.fda.gov/drugsatfda_docs/label/2020/022332Orig1s011lbl.pdf

### 3. Drugs@FDA: Cialis (tadalafil) tablets, application 021368

Type: regulatory

Tier: primary

Source: https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=021368

### 4. Drugs@FDA: Adcirca (tadalafil) tablets, application 022332

Type: regulatory

Tier: primary

Source: https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=022332

### 5. FDA: bulk drug substances used in compounding under section 503A

Type: regulatory

Tier: primary

Source: https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act

### 6. FDA: 503A bulk drug substances category list, updated May 2026

Type: regulatory

Tier: primary

Source: https://www.fda.gov/media/94155/download

### 7. FDA public notification: sexual enhancement product with hidden tadalafil, 2019 to 2026

Type: regulatory

Tier: primary

Source: https://www.fda.gov/drugs/medication-health-fraud/public-notification-green-lumber-contains-hidden-drug-ingredient

### 8. FDA: tainted honey-based products with hidden drug ingredients

Type: regulatory

Tier: primary

Source: https://www.fda.gov/consumers/health-fraud-scams/tainted-honey-based-products-hidden-active-drug-ingredients

### 9. FDA warning letter on products sold as supplements or food with undeclared tadalafil, 20 December 2023

Type: regulatory

Tier: primary

Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/amazoncom-inc-662503-12202023

### 10. FDA warning letter on claims that compounded tadalafil is a generic Cialis, 9 September 2025

Type: regulatory

Tier: primary

Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/getfitmedical-llc-dba-getfitmedical-715801-09092025

### 11. Randomized trial: tadalafil for erectile dysfunction at 24 and 36 hours, 2003

Type: rct

Tier: peer-reviewed

Source: https://pubmed.ncbi.nlm.nih.gov/12837435/

### 12. Randomized trial: tadalafil for pulmonary arterial hypertension, 2009

Type: rct

Tier: peer-reviewed

Source: https://pubmed.ncbi.nlm.nih.gov/19470885/

### 13. Randomized trial: starting ambrisentan plus tadalafil in pulmonary arterial hypertension, 2015

Type: rct

Tier: peer-reviewed

Source: https://pubmed.ncbi.nlm.nih.gov/26308684/

### 14. Randomized dose-finding trial: once daily tadalafil for benign prostatic hyperplasia, 2008

Type: rct

Tier: peer-reviewed

Source: https://pubmed.ncbi.nlm.nih.gov/18722631/

### 15. Systematic review: tadalafil compared with sildenafil for erectile dysfunction, 2017

Type: systematic-review

Tier: peer-reviewed

Source: https://pubmed.ncbi.nlm.nih.gov/28741090/

### 16. Case-crossover study: sudden optic nerve damage (NAION) and PDE5 inhibitor use, 2015

Type: human-trial

Tier: peer-reviewed

Source: https://pubmed.ncbi.nlm.nih.gov/25358826/

### 17. Study: unapproved drug ingredients in dietary supplements named in FDA warnings, 2007 to 2016

Type: reference

Tier: peer-reviewed

Source: https://pubmed.ncbi.nlm.nih.gov/30646238/

### 18. Rat study: tadalafil and simvastatin in pulmonary hypertension, 2012

Type: animal

Tier: peer-reviewed

Source: https://pubmed.ncbi.nlm.nih.gov/22971207/

### 19. National Law Review: FDA's focus returns to compounding and telehealth

Type: legal-analysis

Tier: legal-analysis

Source: https://natlawreview.com/article/fdas-focus-returns-compounding-and-telehealth-another-wave-warning-letters

### 20. NBC News: honey-based sexual supplements may contain Cialis and Viagra ingredients, July 2022

Type: reference

Tier: established-news

Source: https://www.nbcnews.com/health/health-news/honey-based-sexual-supplements-may-contain-cialis-viagra-ingredients-f-rcna37876

### 21. ClinicalTrials.gov NCT05937854: tadalafil for shortness of breath in COPD with high lung pressure

Type: reference

Tier: primary

Source: https://clinicaltrials.gov/study/NCT05937854

### 22. ClinicalTrials.gov NCT05206955: tadalafil compared with placebo in Fontan physiology

Type: reference

Tier: primary

Source: https://clinicaltrials.gov/study/NCT05206955

Last verified: 2026-10-26.

Sources:

- https://clinicaltrials.gov/api/v2/studies?query.intr=tadalafil&filter.overallStatus=RECRUITING%2CNOT_YET_RECRUITING&pageSize=50&sort=StartDate%3Adesc&countTotal=true&fields=NCTId%2CBriefTitle%2COverallStatus%2CPhase%2CLeadSponsorName%2CStartDate%2CLocationCountry%2CLocationState
- https://clinicaltrials.gov/study/NCT05206955
- https://peptideindex.ai/methodology#evidence-grade
- https://peptideindex.ai/methodology#short-answer
- https://pubmed.ncbi.nlm.nih.gov/19470885/
- https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/021368s030lbl.pdf
- https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=021368
- https://www.fda.gov/drugs/medication-health-fraud/public-notification-green-lumber-contains-hidden-drug-ingredient

[^1]: Cialis (tadalafil) tablets label, revised February 2018 https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/021368s030lbl.pdf
[^2]: Adcirca (tadalafil) tablets label, revised September 2020 https://www.accessdata.fda.gov/drugsatfda_docs/label/2020/022332Orig1s011lbl.pdf
[^3]: Drugs@FDA: Cialis (tadalafil) tablets, application 021368 https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=021368
[^4]: Drugs@FDA: Adcirca (tadalafil) tablets, application 022332 https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=022332
[^5]: FDA: bulk drug substances used in compounding under section 503A https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act
[^6]: FDA: 503A bulk drug substances category list, updated May 2026 https://www.fda.gov/media/94155/download
[^7]: FDA public notification: sexual enhancement product with hidden tadalafil, 2019 to 2026 https://www.fda.gov/drugs/medication-health-fraud/public-notification-green-lumber-contains-hidden-drug-ingredient
[^8]: FDA: tainted honey-based products with hidden drug ingredients https://www.fda.gov/consumers/health-fraud-scams/tainted-honey-based-products-hidden-active-drug-ingredients
[^9]: FDA warning letter on products sold as supplements or food with undeclared tadalafil, 20 December 2023 https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/amazoncom-inc-662503-12202023
[^10]: FDA warning letter on claims that compounded tadalafil is a generic Cialis, 9 September 2025 https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/getfitmedical-llc-dba-getfitmedical-715801-09092025
[^11]: Randomized trial: tadalafil for erectile dysfunction at 24 and 36 hours, 2003 https://pubmed.ncbi.nlm.nih.gov/12837435/
[^12]: Randomized trial: tadalafil for pulmonary arterial hypertension, 2009 https://pubmed.ncbi.nlm.nih.gov/19470885/
[^13]: Randomized trial: starting ambrisentan plus tadalafil in pulmonary arterial hypertension, 2015 https://pubmed.ncbi.nlm.nih.gov/26308684/
[^14]: Randomized dose-finding trial: once daily tadalafil for benign prostatic hyperplasia, 2008 https://pubmed.ncbi.nlm.nih.gov/18722631/
[^15]: Systematic review: tadalafil compared with sildenafil for erectile dysfunction, 2017 https://pubmed.ncbi.nlm.nih.gov/28741090/
[^16]: Case-crossover study: sudden optic nerve damage (NAION) and PDE5 inhibitor use, 2015 https://pubmed.ncbi.nlm.nih.gov/25358826/
[^17]: Study: unapproved drug ingredients in dietary supplements named in FDA warnings, 2007 to 2016 https://pubmed.ncbi.nlm.nih.gov/30646238/
[^18]: Rat study: tadalafil and simvastatin in pulmonary hypertension, 2012 https://pubmed.ncbi.nlm.nih.gov/22971207/
[^19]: National Law Review: FDA's focus returns to compounding and telehealth https://natlawreview.com/article/fdas-focus-returns-compounding-and-telehealth-another-wave-warning-letters
[^20]: NBC News: honey-based sexual supplements may contain Cialis and Viagra ingredients, July 2022 https://www.nbcnews.com/health/health-news/honey-based-sexual-supplements-may-contain-cialis-viagra-ingredients-f-rcna37876
[^21]: ClinicalTrials.gov NCT05937854: tadalafil for shortness of breath in COPD with high lung pressure https://clinicaltrials.gov/study/NCT05937854
[^22]: ClinicalTrials.gov NCT05206955: tadalafil compared with placebo in Fontan physiology https://clinicaltrials.gov/study/NCT05206955