Rankings / Hormones & Endocrine
Sildenafil (Viagra)
Hormones & Endocrine · PDE5 inhibitor
Tier A
Bottom line
Read Off Label grades Sildenafil (Viagra) as A (8.0/10) based on very strong evidence, very strong benefit magnitude, and a low-med-risk safety profile.
Generic since 2017 — dramatic price drop.
Typical use: 25-100 mg PO 30-60 min before activity; take on empty stomach for faster onset — Rx; generics widely available; Hims/Roman-style telehealth.
What this is
Generic since 2017 — dramatic price drop. Fang 2021 and others show observational Alzheimer risk reduction in PDE5i users — mechanism via cerebral blood flow and Aβ modulation plausible. Take food separation seriously — high-fat meal delays absorption >1 hour. Do not combine with any nitrate. A sildenafil oral film (Vybrique) gained FDA approval in 2026 as a more convenient dosing format.
Mechanism
Selective phosphodiesterase-5 inhibitor; prevents cGMP breakdown → sustained smooth muscle relaxation in corpus cavernosum → erection (upon sexual stimulation, not spontaneous); also pulmonary vasodilation
Dose & route
25-100 mg PO 30-60 min before activity; take on empty stomach for faster onset
Citations
- https://pubmed.ncbi.nlm.nih.gov/34811549/
- https://pubmed.ncbi.nlm.nih.gov/9462139/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC8681697/
- https://clinicaltrials.gov/study/NCT00547352
Links go to the source. If a link is dead or you want something re-checked, let me know.
Common questions
- Does Sildenafil (Viagra) work?
- Read Off Label rates the evidence for Sildenafil (Viagra) as Very Strong and the benefit magnitude as very strong, producing an overall grade of A (8.0/10). Generic since 2017 — dramatic price drop.
- Is Sildenafil (Viagra) safe?
- Sildenafil (Viagra) has a low-med risk profile in published human data. Legal status: Rx; generics widely available; Hims/Roman-style telehealth. This is not medical advice — see the disclaimer.
- What is the typical dose for Sildenafil (Viagra)?
- 25-100 mg PO 30-60 min before activity; take on empty stomach for faster onset
- How does Sildenafil (Viagra) work?
- Selective phosphodiesterase-5 inhibitor; prevents cGMP breakdown → sustained smooth muscle relaxation in corpus cavernosum → erection (upon sexual stimulation, not spontaneous); also pulmonary vasodilation
This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.