Sexual wellness · Sildenafil
Sildenafil — the original PDE5 inhibitor.
Sildenafil is the first-generation PDE5 inhibitor, FDA-approved in 1998 as Viagra. Twenty-plus years of clinical data, predictable 4–6 hour duration, fast onset when taken on an empty stomach. Sits in our catalog at the price the generic should always have cost.
What it is
Sildenafil is a phosphodiesterase-5 (PDE5) inhibitor — a class of small-molecule drugs that block the enzyme responsible for breaking down cyclic GMP in penile vascular tissue. The result is sustained vasodilation in response to sexual stimulation, which mechanically supports erection.
Originally trialed as a blood-pressure medication (where it underperformed), the side-effect profile redirected it to erectile dysfunction. Patent expired in 2017, so generic sildenafil is now widely available at a fraction of branded Viagra cost. Vektor prescribes the generic.
How it works
Sexual arousal triggers nitric oxide release in penile tissue, which activates guanylate cyclase, which produces cyclic GMP, which relaxes smooth muscle in the corpora cavernosa to allow blood inflow. PDE5 normally breaks down cyclic GMP to reset the system. Sildenafil inhibits PDE5, letting cGMP accumulate longer and sustaining the response.
Critically: sildenafil doesn't cause erection — it amplifies the body's natural response when arousal is present. Without the upstream NO signal, the drug does nothing.
Who it's for
Sildenafil tends to fit:
- Patients new to PDE5 inhibitors — well-studied, predictable
- Patients who want on-demand (not daily) dosing
- Patients prioritizing fast onset over long duration
- Patients with stable cardiovascular status (no nitrates, no severe BP issues)
It does not fit patients on nitrates (any form), patients with severe hypotension, or recent stroke / MI. We screen carefully on intake.
Dosing and cadence
Typical dosing: 25, 50, or 100mg taken 30–60 minutes before sexual activity, on an empty stomach for fastest onset. Most patients start at 50mg and titrate. Maximum recommended dose is 100mg, no more than once per 24 hours.
Heavy meals — particularly high-fat — delay onset significantly. Take on an empty stomach when timing matters.
What to expect
Onset 30–60 minutes after dosing. Effective window 4–6 hours. Common side effects: flushing, headache, mild nasal congestion, occasional visual changes (blue tint). Most are dose-related and resolve as the drug clears.
How Vektor handles it
Generic sildenafil from a U.S. retail or 503A pharmacy partner. We screen cardiovascular status, current medications (especially nitrates and alpha-blockers), and prior PDE5 trials on intake. If sildenafil under-performs, tadalafil is a straightforward swap, and compounded combination protocols are available for patients who've plateaued on monotherapy.
Pricing
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Membership tiers + per-protocol pricing for every peptide in our catalog.
Frequently asked
- Sildenafil vs. tadalafil — which is better?
- Different profiles, not different effectiveness. Sildenafil is on-demand only (4–6 hour window), fast onset, food-sensitive. Tadalafil has a 24–36 hour window and can be dosed daily at low dose. Patients pick based on lifestyle, not on which is “better.”
- Why does food slow down sildenafil?
- Sildenafil is highly fat-soluble. A high-fat meal slows gastric emptying and reduces peak concentration by 30–40%. For predictable onset, take it on an empty stomach. Tadalafil doesn't have this issue, which is one reason patients often prefer it.
- Is generic sildenafil the same as Viagra?
- Yes — same active molecule, same FDA bioequivalence standard. We prescribe FDA-approved generic from licensed U.S. pharmacies. The price difference is purely brand premium.
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