Sildenafil: what the human evidence actually shows
Sildenafil is a PDE5 inhibitor, FDA-approved for erectile dysfunction and (as Revatio) for pulmonary arterial hypertension. It has a shorter half-life than tadalafil — roughly 4 hours — giving an effective window of about 4 to 6 hours, and it works best taken on an empty stomach. It is available as a low-cost generic.
What the evidence actually shows
Extensively studied and clearly effective for erectile dysfunction across large randomised trials, with decades of post-marketing data. Along with tadalafil, this is among the best-evidenced treatments covered on this site.
Absolute versus relative: reading the number correctly
Trial results are usually reported as relative figures, because relative figures are larger and therefore more persuasive. A "20% reduction in cardiovascular events" sounds transformative. The absolute reduction in SELECT was from 8.0% to 6.5% — about 1.5 percentage points over roughly three years. Both statements describe the same result honestly; only one of them tells you what to expect for yourself.
The same applies to weight-loss figures. A mean reduction of 20.9% is a mean. Individual results in these trials ranged from substantial loss to none at all, and a mean tells you nothing about where you personally would land. Anyone quoting a trial average as a promise is misusing it.
Funding and conflicts of interest
Every pivotal trial in this field was funded by the company that manufactures the drug it tested. That is normal in pharmaceutical research and it does not make the results false — these are large, well-conducted, peer-reviewed studies. It does mean the funding belongs in the citation every time, particularly for head-to-head trials where the funder makes the winning drug. SURMOUNT-5 was funded by Eli Lilly and found Lilly's drug superior. The result is plausible and consistent with the separate trial programmes; the disclosure still belongs beside it.
Where this sits against the other evidence
No single trial should be read alone. The strength of the GLP-1 evidence base is that multiple independent trial programmes — SURMOUNT for tirzepatide, STEP for semaglutide, SCALE for liraglutide, SELECT for cardiovascular outcomes — point in a consistent direction across tens of thousands of participants. That consistency is what makes the class credible.
What that consistency does not do is extend to products the trials never tested. Every one of those programmes studied an FDA-approved subcutaneous injection. None studied a compounded preparation, a microdose regimen, or an orally disintegrating tablet. The evidence is strong exactly where it was collected and silent everywhere else, and the gap between those two things is where most of the marketing in this industry operates.
Frequently asked questions
What does Sildenafil cost through telehealth?
It is available as an inexpensive FDA-approved generic — price that at a pharmacy before paying a subscription for a compounded version.
Is Sildenafil FDA-approved?
Sildenafil is FDA-approved and available as an inexpensive generic. As with tadalafil, there is rarely a good reason to pay more for a compounded troche, a 'proprietary blend' or a stacked combination product. Those are not FDA-approved and have no demonstrated adva
Does Sildenafil work?
Extensively studied and clearly effective for erectile dysfunction across large randomised trials, with decades of post-marketing data. Along with tadalafil, this is among the best-evidenced treatments covered on this site.
Sources
- U.S. Food and Drug Administration — approved labels and compounding guidance for this molecule.
- PubMed / NIH — indexed human clinical literature.
- ClinicalTrials.gov — registered trials, where they exist.
- Our source hierarchy and pricing-verification methodology.