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Head-to-head evidence comparison — which supplement is right for you?
Sildenafil (Viagra) wins 3 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Mostly mechanism / observational
Top outcomes
Verdict
Mostly mechanism / observational
Top outcomes
Shared outcomes (1)
Outcomes where both Sildenafil (Viagra) and Tadalafil have evidence — compare verdict strength side-by-side.
Approved on-demand ED dosing is 25-100 mg taken ~30-60 minutes before activity (50 mg typical start). PAH dosing (Revatio) is 20 mg three times daily. Any off-label use is clinician-directed; this is not an approved longevity regimen.
any
Oral tablet (sildenafil citrate)
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.
any
Low daily-dose oral tablet
Acute (~30-60 min onset)
Weeks
Years
Years
Years
Years
Acute to weeks
With interacting drugs
Oral sildenafil in the treatment of erectile dysfunction.
The New England Journal of Medicine (1998) · Rct
Two sequential double-blind randomized trials of on-demand oral sildenafil in men with erectile dysfunction
Efficacy of PDE-5-inhibitors for erectile dysfunction. A comparative meta-analysis of fixed-dose regimen randomized controlled trials administering the International Index of Erectile Function in broad-spectrum populations.
International Journal of Impotence Research (2006) · Meta analysis
Comparative meta-analysis pooling fixed-dose RCTs of sildenafil, tadalafil, and vardenafil
Sildenafil citrate therapy for pulmonary arterial hypertension.
The New England Journal of Medicine (2005) · Rct
SUPER-1: randomized, double-blind, placebo-controlled trial in 278 patients with PAH
Phosphodiesterase type-5 inhibitor use in type 2 diabetes is associated with a reduction in all-cause mortality.
Heart (British Cardiac Society) (2016) · Observational
Observational cohort of PDE5-inhibitor use in type-2 diabetics at high cardiovascular risk
Using Big Data to Uncover Association Between Sildenafil Use and Reduced Risk of Alzheimer's Disease.
Studies in health technology and informatics (2023) · Observational
Large real-world database study linking PDE5-inhibitor use to lower Alzheimer's incidence
Cardiovascular outcomes among sildenafil users: results of the International Men's Health Study.
International journal of clinical practice (2008) · Observational
Observational analysis of cardiovascular outcomes among PDE5-inhibitor users (international registry)
Sildenafil (Viagra) has a higher evidence score (3.8/10 vs 3/10) and wins in 3 of 3 categories.
No known interactions between Sildenafil (Viagra) and Tadalafil have been documented in our database. However, always consult a healthcare provider before combining supplements.