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Tadalafil (PDE5 inhibitor)
A long-acting PDE5 inhibitor (Cialis) approved for erectile dysfunction, BPH, and pulmonary hypertension, drawing geroscience interest from large observational datasets linking PDE5-inhibitor use to lower all-cause mortality, fewer cardiovascular events, and possibly reduced Alzheimer's risk. The catch: this is association, not causation — there is no longevity RCT. A prescription drug used off-label, not a supplement.
Prescription medication — not a dietary supplement
Tadalafil is a prescription (or investigational) drug, not a supplement. It is included here for reference because people research and discuss it (often used off-label) — not as a recommendation. Take it only under a qualified clinician's supervision and only as prescribed; do not source it from grey-market vendors, where identity, purity, and dosing are unverified. The evidence below reflects its clinical trials.
What the evidence says
Tadalafil doesn't have enough studies with structured effect-size data yet to pool a verdict. Browse the studies below for individual findings.
Most evidence is from high-quality meta-analyses and randomised trials published 2007–2026.
Based on 113 studies · 13 meta-analyses · 87 RCTs
Confidence
High confidenceBy outcome
PDE5 inhibitors like tadalafil show consistent observational associations with lower all-cause mortality, fewer cardiovascular events, and possibly reduced dementia, plus a plausible nitric-oxide/vascular mechanism — but the data are entirely associational with strong healthy-user confounding and no longevity RCT, so the geroprotector case is suggestive but unproven.
96 randomised trials
92% were about Tadalafil in an audit of 50 of them
Every randomised or controlled trial of Tadalafil indexed in PubMed, not a hand-picked subset. Meta-analyses and systematic reviews are deliberately excluded from this count: most of them cover many compounds at once, so counting them would inflate it.
PubMed · as of Sep 2026
37 trials ongoing or recruiting · 185 completed on ClinicalTrials.gov
65 of the completed trials have posted results
Registered trials show research momentum for Tadalafil, not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed. They are never counted toward the evidence rating above.
Browse these trials on ClinicalTrials.govClinicalTrials.gov · as of Nov 2026
Tadalafil is a long-acting phosphodiesterase-5 (PDE5) inhibitor — the same class as sildenafil (Viagra) — approved for erectile dysfunction, benign prostatic hyperplasia, and pulmonary arterial hypertension.
By blocking PDE5 it raises cyclic GMP, enhancing nitric-oxide-mediated vasodilation and improving endothelial function, with additional effects on mitochondrial signaling and inflammation that are relevant to vascular and brain aging.
Its longevity interest is almost entirely observational but striking in scale: large cohort and insurance-claims analyses have found that men who use PDE5 inhibitors have lower all-cause mortality and fewer major cardiovascular events than non-users, and several big-data studies report an association between PDE5-inhibitor use and reduced incidence of Alzheimer's disease and vascular dementia.
There is also mechanistic and small-trial work on endothelial and metabolic benefits.
The honest and important caveat is that all of this is associational: men prescribed PDE5 inhibitors differ systematically from those who are not (healthier, more active, better healthcare access — classic 'healthy-user' confounding), and no randomized trial has tested whether tadalafil extends lifespan or prevents dementia.
PDE5 inhibitors are generally well tolerated (headache, flushing, nasal congestion, indigestion), but they are dangerous combined with nitrates (severe hypotension) and need caution with alpha-blockers and certain heart conditions.
Tadalafil is a prescription drug used off-label for its proposed vascular-aging benefits; it is not a dietary supplement. The score reflects consistent but observational human signals and a plausible vascular mechanism, against the absence of any longevity RCT and clear healthy-user confounding.
Tadalafil blocks PDE5, raising cyclic GMP and prolonging nitric-oxide-mediated vasodilation — improving endothelial function.
Enhanced NO signaling improves vascular and possibly cerebral blood flow, the proposed basis for cardiovascular and dementia associations.
cGMP signaling has additional effects on mitochondrial function and inflammation relevant to tissue aging.
How Tadalafil works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Absolute contraindication — dangerous hypotension.
Avoid until cleared by a clinician.
Use low doses and monitor blood pressure.
Combined PDE5 inhibitor + nitrate causes severe, potentially fatal hypotension — an absolute contraindication.
Additive blood-pressure lowering — use caution and lower doses.
Raise tadalafil levels; dose reduction advised.
Tip: Vasodilatory; usually mild and transient.
Tip: Class effects; often dose-related.
Tip: Seek care; avoid nitrates; An erection lasting 4 hours or longer is an emergency whether or not it hurts: go to an emergency department now. One approaching 3 to 4 hours, or a painful erection unrelated to arousal, needs urgent medical assessment now. Do not wait.
Tadalafil has an evidence score of 3/10 — emerging evidence based on 113 indexed studies. A long-acting PDE5 inhibitor (Cialis) approved for erectile dysfunction, BPH, and pulmonary hypertension, drawing geroscience interest from large observational datasets linking PDE5-inhibitor use to lower all-cause mortality, fewer cardiovascular events, and possibly reduced Alzheimer's risk. The catch: this is association, not causation — there is no longevity RCT. A prescription drug used off-label, not a supplement. Representative study: PMID 27465053.
Dosing for Tadalafil: Off-label longevity/vascular use mirrors low approved dosing (e.g. tadalafil 2.5–5 mg once daily, the dose used for BPH/daily ED) under a clinician. Not an approved longevity regimen. (the approved label dose, not a dose from the cited studies, which are observational and state no dose). Individual needs vary, so check the right dose for you with a healthcare provider.
Timing is flexible for Tadalafil — consistent daily use matters more than the time of day. Tadalafil is long-acting (~17.5 h half-life); the low daily dose gives steady vascular effects.
Tadalafil should be used with caution — talk to a healthcare provider before taking it. Reported side effects include hypotension / priapism / sudden vision or hearing changes, headache / flushing, nasal congestion / indigestion / back pain. How often they occur is not established for all of them. Use caution if any of these apply to you: Concurrent nitrates (any form); Recent cardiovascular event / unstable angina; Severe hypotension.
Testosterone (TRT)
Too few graded studiesThe primary male androgen and a prescription medicine with US FDA-approved products for specified causes of male hypogonadism, and a Schedule III controlled substance in the US. For men with genuinely low testosterone, randomized trials show real benefits: the Testosterone Trials (TTrials) improved sexual function, mood, anemia and bone density in older hypogonadal men, and the large TRAVERSE trial found TRT non-inferior to placebo for major cardiac events. But those benefits were modest and indication-specific, NOT a longevity or anti-aging result. It is prescription-only in Germany and Austria. Non-medical, supraphysiologic and 'anti-aging' use is not established as safe or effective for longevity and carries serious harms — erythrocytosis, suppressed sperm production/fertility, cardiovascular and psychiatric risk. This is a harm-reduction reference, not a recommendation, and testosterone is NOT a dietary supplement.
Nicotinamide Riboside
Too few graded studiesA vitamin B3 precursor that reliably raises cellular NAD+ levels and is well tolerated — but human trials have so far shown mostly null or mixed results on the functional outcomes (muscle, metabolism, blood pressure, cognition) that elevation is meant to drive.
MitoQ
Too few graded studiesA mitochondria-targeted antioxidant — CoQ10 conjugated to a triphenylphosphonium (TPP+) cation so it accumulates several-hundred-fold inside mitochondria. Sold OTC as a supplement. Its best human signal is improved endothelial/vascular function in older adults (one small RCT); several trials are null (Parkinson's, exercise adaptation), and almost all outcomes are surrogate/biomarker, not hard clinical endpoints.
Yohimbine
Too few graded studiesThe purified alkaloid (not crude yohimbe bark) — an alpha-2 adrenoceptor antagonist with modest evidence for erectile dysfunction and fasted fat loss, but real anxiety and cardiovascular risks and supplement potency that may differ from the label.
Explore: Best supplements for Men's Health
Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 113 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
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