Tadalafil

A prescription PDE5 inhibitor approved for erectile dysfunction and benign prostatic hyperplasia, with a much longer terminal half-life (~17.5 h) than sildenafil. It appears in biohacking stacks on the back of surrogate endothelial research, which is not what it is approved for. Separately, aminotadalafil and nortadalafil are unapproved analogs that turn up as undeclared adulterants in illicit sexual-enhancement products — they are not alternative names for tadalafil.

Tadalafil blocks PDE5, the enzyme that breaks down cGMP — the signalling molecule that keeps smooth muscle in blood-vessel walls relaxed. Blocking it means cGMP persists, vessels stay dilated and blood flow increases where nitric-oxide signalling is already active. That is why it does nothing without arousal in erectile dysfunction: it amplifies an existing signal rather than creating one. The same smooth-muscle relaxation in the prostate and bladder neck is why it also carries a benign prostatic hyperplasia indication. Its distinguishing feature against others in the class is duration — a terminal half-life around 17.5 hours rather than a few hours.

STRONG for its approved indications, erectile dysfunction and benign prostatic hyperplasia — one of the best-evidenced compounds on this list, with decades of trial data behind it. For endothelial outcomes: LIMITED, and confined to clinical populations, on surrogate measures rather than health outcomes. For gym performance or general health benefit in healthy people: NONE SHOWN.

• STRONG for its two approved indications, erectile dysfunction and benign prostatic hyperplasia, on decades of randomised trials. This is among the best-evidenced compounds in this catalogue.
• LIMITED for endothelial function, and confined to clinical populations on surrogate measures — changes in vascular markers rather than health outcomes.
• NONE SHOWN for gym performance, "pump", or general health benefit in healthy people. That use rests on mechanism plus extrapolation from the surrogate work above.
• It also has an approved use in pulmonary arterial hypertension under a separate product, which is a specialist indication and not a general cardiovascular benefit.
• Counterfeit and adulterated products sold outside pharmacies frequently contain undeclared PDE5 analogs such as aminotadalafil and nortadalafil, which is a recognised FDA enforcement problem rather than a theoretical one.

Terminal half-life around 17.5 hours, substantially longer than others in the class, so effects and adverse effects both persist well beyond a single day. It is metabolised by CYP3A4, which is the basis of several of its interactions. Back pain and myalgia are labelled adverse effects and can appear with a delay; there is no good evidence they occur more often than with shorter-acting alternatives.

Headache, flushing, nasal congestion, back pain and myalgia are labelled effects and can be delayed; there is no good evidence they are more frequent than with sildenafil, and the half-life explanation for that is not established. TWO absolute contraindications, not one: nitrates in any form, and guanylate cyclase stimulators such as riociguat — either combination can drop blood pressure catastrophically. Clinically important hypotension also occurs with alpha-blockers, other antihypertensives and substantial alcohol. Priapism is rare but a surgical emergency. New visual or hearing changes warrant prompt assessment. Serious hypersensitivity reactions occur. Anyone whose heart may not tolerate sexual activity, and anyone with significant kidney or liver impairment, needs medical assessment first. Products from outside lawful channels vary widely in actual content and are a common vehicle for undeclared analogs.

• Anyone taking nitrates in any form, including recreational nitrites
• Anyone taking riociguat or another guanylate cyclase stimulator
• Anyone whose cardiovascular condition makes sexual activity inadvisable
• Anyone with significant kidney or liver impairment, without prescriber assessment
• Anyone with a history of non-arteritic anterior ischaemic optic neuropathy
• Anyone with a serious hypersensitivity reaction to it

• Nitrates in any form — an absolute contraindication. The combination can drop blood pressure catastrophically, and this includes recreational nitrites.
• Guanylate cyclase stimulators such as riociguat — the second absolute contraindication, and the one most often omitted.
• Alpha-blockers, other blood-pressure medicines and substantial alcohol, all of which can produce clinically important hypotension.
• Strong CYP3A4 inhibitors and inducers, which raise or lower its levels significantly.
• Any product bought outside licensed pharmacies, which is a common vehicle for undeclared analogs.

• Whether your heart can tolerate sexual activity at all — this is a cardiovascular assessment that belongs before the prescription, not after.
• Blood pressure, particularly for anyone also taking alpha-blockers or other antihypertensives.
• Any sudden vision or hearing change, which needs prompt medical assessment rather than watchful waiting.
• An erection lasting more than four hours, which is a surgical emergency.
• Kidney and liver function, which limit its use.

No withdrawal syndrome and no rebound. Effects fade as the drug clears, which given the long half-life takes a day or two rather than hours. Erectile function returns to whatever it was before, since the drug treats the symptom rather than the cause — and the underlying cause is frequently cardiovascular, which is the reason erectile dysfunction is worth investigating rather than only medicating.

US: prescription-only (not scheduled). Products offered outside lawful prescription channels may be falsified or mislabeled.

Papers about this compound, not proof of the claims above. A title says what was studied, which is sometimes a negative result or a different question entirely.

• A Systematic Review and Meta-Analysis of the Efficacy and Safety of Tamsulosin Plus Tadalafil Compared With Tamsulosin Alone in Treating Males With Lower Urinary Tract Symptoms Secondary to Benign Prostrate Hyperplasia
  Am J Mens Health, 2023
• The Efficacy of Tadalafil Daily vs on Demand in the Treatment of Erectile Dysfunction: A Systematic Review and Meta-analysis
  Urology, 2018
• Direct comparison of tadalafil with sildenafil for the treatment of erectile dysfunction: a systematic review and meta-analysis
  Int Urol Nephrol, 2017

• Direct comparison of tadalafil with sildenafil for the treatment of erectile dysfunction: a systematic review and meta-analysisInt Urol Nephrol · 2017
• Tadalafil for the treatment of benign prostatic hyperplasiaExpert Opin Pharmacother · 2019
• Efficacy and safety of long-term tadalafil 5 mg once daily combined with sildenafil 50 mg as needed at the early stage of treatment for patients with erectile dysfunctionAndrologia · 2015
• Benefits of Tadalafil and Sildenafil on Mortality, Cardiovascular Disease, and DementiaAm J Med · 2025
• Tadalafil Alone or in Combination with Tamsulosin for the Management for LUTS/BPH and EDCurr Urol Rep · 2020
• TadalafilProfiles Drug Subst Excip Relat Methodol · 2011
• Tadalafil for Treatment of Fetal Growth Restriction: A Review of Experimental and Clinical StudiesBiomedicines · 2024
• Tadalafil and Steroid Hormones Interactions in Adipose, Bone and Prostate Tissues: Focus on Translational PerspectivesInt J Mol Sci · 2022
• Potential beneficial impacts of tadalafil on cardiovascular diseasesJ Chin Med Assoc · 2025
• Tadalafil Use in Cardiovascular DiseaseCardiol Rev · 2025
• Tadalafil: in pulmonary arterial hypertensionDrugs · 2010
• Tadalafil for the treatment of pulmonary arterial hypertensionExpert Opin Pharmacother · 2010