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Vardenafil (PDE5 inhibitor)
A potent, intermediate-acting PDE5 inhibitor (Levitra; Staxyn orodispersible tablet) for erectile dysfunction — the same drug class as sildenafil and tadalafil. It has a robust randomized-trial base for ED, including hard-to-treat populations like diabetes and post-prostatectomy. A prescription drug, not a supplement, and it carries a notable QT-prolongation caution on top of the class-wide nitrate contraindication.
Prescription medication — not a dietary supplement
Vardenafil (Levitra) 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
Vardenafil (Levitra) 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 2001–2026.
Based on 25 studies · 3 meta-analyses · 12 RCTs
Confidence
High confidenceBy outcome
Vardenafil has a strong, well-replicated RCT and meta-analytic base for erectile dysfunction, including efficacy in hard-to-treat populations (diabetes, post-radical-prostatectomy) — for that approved use the evidence is strong. The overall score is held below the top tier because it is a prescription-only drug rather than a supplement and because it carries a notable QT-prolongation caution on top of the class-wide nitrate contraindication.
No trials currently enrolling · 68 completed on ClinicalTrials.gov
8 of the completed trials have posted results
Registered trials show research momentum for Vardenafil (Levitra), not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed.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
Vardenafil is an oral phosphodiesterase-5 (PDE5) inhibitor marketed as Levitra (film-coated tablet) and Staxyn (orodispersible tablet, ODT) for erectile dysfunction.
Like sildenafil and tadalafil it works by blocking PDE5, which raises cyclic GMP and prolongs nitric-oxide-mediated relaxation of penile smooth muscle, enhancing erectile blood flow in response to sexual stimulation.
Vardenafil is highly potent, so it is dosed at low milligram amounts, and it sits between sildenafil and tadalafil on duration — a roughly 4-5 hour half-life with onset around 30-60 minutes that is blunted by high-fat meals.
The randomized-trial evidence for erectile dysfunction is robust: large double-blind, placebo-controlled trials (the first being Porst's at-home study) show dose-dependent, clinically meaningful improvement on the International Index of Erectile Function (IIEF), and the drug retains efficacy in difficult populations — men with diabetes and men with erectile dysfunction after radical prostatectomy — where erectile dysfunction is harder to treat.
Comparative and network meta-analyses place vardenafil among the effective, well-tolerated PDE5 inhibitors. Tolerability is generally good; the most common adverse effects are vasodilatory — headache, flushing, rhinitis (nasal congestion), and dyspepsia.
A distinguishing safety feature is that vardenafil’s labeling carries a specific QT-prolongation precaution that the other PDE5 inhibitors’ labels do not, so it should be avoided in men with congenital long-QT syndrome and in those taking Class IA or Class III antiarrhythmics or other QT-prolonging drugs.
As with the entire class, vardenafil is absolutely contraindicated with nitrates in any form, because the combination can cause severe, potentially fatal hypotension; it requires caution with alpha-blockers and other antihypertensives, and shares the rare but serious class risks of priapism, non-arteritic anterior ischemic optic neuropathy (NAION), and sudden hearing loss.
It is a prescription medication used under clinician supervision, described for information — not a supplement and not a recommendation. The score reflects strong, well-replicated efficacy for erectile dysfunction held below the top tier by the prescription-only status and the added QT-prolongation caution.
Vardenafil potently blocks PDE5, raising cyclic GMP and prolonging nitric-oxide-mediated smooth-muscle relaxation — the basis for its erectile effect.
Enhanced NO/cGMP signaling relaxes penile smooth muscle and increases blood flow in response to sexual stimulation, improving erectile function.
Vardenafil modestly prolongs the QT/QTc interval; a head-to-head study found the effect small and comparable to sildenafil, but its labeling still carries a specific QT precaution underlying its caution with antiarrhythmics and other QT-prolonging drugs.
How Vardenafil (Levitra) 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 — vardenafil’s labeling carries a specific QT-prolongation precaution.
Avoid until cleared by a clinician.
Use low starting doses and monitor blood pressure.
Discuss the rare risk of optic-nerve injury with a clinician before use.
Combined PDE5 inhibitor + nitrate causes severe, potentially fatal hypotension — an absolute contraindication.
Vardenafil carries a specific QT-prolongation precaution in its labeling; combining with antiarrhythmics (e.g. quinidine, procainamide, amiodarone, sotalol) or other QT-prolonging agents raises arrhythmia risk — avoid.
Additive blood-pressure lowering — use caution and lower starting doses.
Raise vardenafil levels (e.g. ritonavir, ketoconazole, itraconazole); dose reduction or avoidance advised.
Tip: Vasodilatory; usually mild and transient.
Tip: Class/dose-related; generally transient.
Tip: Avoid in long-QT syndrome and with antiarrhythmics/QT-prolonging drugs; clinician assessment for at-risk patients.
Tip: Seek urgent 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.
Vardenafil (Levitra) has an evidence score of 3.6/10 — emerging evidence based on 25 indexed studies, including 1 meta-analysis. A potent, intermediate-acting PDE5 inhibitor (Levitra; Staxyn orodispersible tablet) for erectile dysfunction — the same drug class as sildenafil and tadalafil. It has a robust randomized-trial base for ED, including hard-to-treat populations like diabetes and post-prostatectomy. A prescription drug, not a supplement, and it carries a notable QT-prolongation caution on top of the class-wide nitrate contraindication. Representative study: PMID 30523399.
Dosing for Vardenafil (Levitra): Approved on-demand ED dosing is 5-20 mg taken ~30-60 minutes before activity (10 mg typical start for the film-coated tablet); the orodispersible Staxyn tablet is 10 mg. Any use is clinician-directed and prescription-only; this is not a supplement regimen. Individual needs vary, so check the right dose for you with a healthcare provider.
Timing is flexible for Vardenafil (Levitra) — consistent daily use matters more than the time of day. Intermediate-acting; onset ~30-60 minutes and a high-fat meal slows/blunts absorption, so it is often taken on a relatively empty stomach.
Vardenafil (Levitra) should be used with caution — talk to a healthcare provider before taking it. Reported side effects include priapism / NAION (sudden vision loss) / sudden hearing loss / symptomatic hypotension, qT-interval prolongation, headache / flushing. How often they occur is not established for all of them. Use caution if any of these apply to you: Concurrent nitrates (any form); Congenital long-QT syndrome or concurrent Class IA/III antiarrhythmics or other QT-prolonging drugs; Recent cardiovascular event / unstable angina.
What side effects does Vardenafil (Levitra) have?Don't take this if…
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.
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Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 25 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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