For Men · Prescription Tablet

Sildenafil

The proven first step, on your schedule.

The clinically established treatment for erectile dysfunction — the generic form of Viagra®, now prescribed online, reviewed by licensed providers, and shipped discreetly from U.S. pharmacies to all 50 states.

Your price depends on the dose your provider prescribes

$35/mo Most people start here

Start your online visit →

A few private questions, then a licensed provider reviews your answers.

100% Online Licensed Providers Discreet Shipping No Insurance
At a glance
Onset
30–60 minutes
Duration
4–6 hours
Use
As needed
Class
PDE5 inhibitor
Form
Oral tablet
For
Men
The basics

What is sildenafil?

What it is
The generic form of Viagra®
Drug class
PDE5 inhibitor
Active ingredient
Sildenafil citrate
Treats
Erectile dysfunction
Available doses
25 mg · 50 mg · 100 mg
Onset & duration
30–60 minutes · lasts 4–6 hours
Prescription
Provider-reviewed · no insurance required
Shipping
Discreet, unmarked · all 50 states
Start your online visit →

Sildenafil citrate is the generic form of Viagra® — the original PDE5 inhibitor approved for erectile dysfunction. As an FDA-approved generic, it contains the identical active ingredient to the brand at a far more accessible price.

It's intended for use as needed before sexual activity rather than on a daily schedule. Because it relies on natural arousal to work, sildenafil supports your body's own response rather than overriding it — one of the most prescribed and studied ED medications in the world, with a well-characterized profile.

It comes in three strengths — 25 mg, 50 mg, and 100 mg — so a provider can dial in what works for your body, and adjust over time based on how you respond.

Understanding the cause

Why does erectile dysfunction happen in the first place?

Erectile dysfunction — difficulty getting or keeping an erection firm enough for sex — is one of the most common conditions men face, and it becomes more common with age. An erection depends on healthy blood flow, so ED can stem from vascular, nerve, hormonal, or psychological factors, and it's often linked to conditions like high blood pressure, diabetes, and heart disease, as well as stress, anxiety, and lifestyle factors.

It's more common than most men think

ED affects millions of men and grows more common with age. It's a routine reason men talk to a provider, not a rare or embarrassing problem.

It's highly treatable

For most men, ED responds well to treatment. PDE5 inhibitors like sildenafil are a well-established first-line option, and a licensed provider can help you find what works.

Know the difference

Prescription sildenafil vs. OTC supplements vs. lifestyle changes — what actually works?

The short answer: over-the-counter "enhancement" supplements aren't reviewed for ED and their contents vary, lifestyle changes help gradually, and a prescription PDE5 inhibitor like sildenafil is clinically proven to improve erections on demand — with a provider reviewing your health history first.

 OTC "enhancement" supplementsLifestyle changesPrescription sildenafil (Rx)
What it doesMarketed for "performance," contents unregulatedSupports overall vascular healthClinically shown to improve erections
Evidence for EDNot FDA-reviewed for EDHelpful, but gradualDecades of clinical trials
When it worksVaries / unverifiedWeeks to monthsWithin 30–60 minutes
Provider involvedNoNoYes — reviews your health history first
Regulated & dispensed by a pharmacyNoN/AYes — Rx only, U.S. pharmacies

Many men try OTC supplements first, can't verify what's actually in them, and see little effect. A prescription tablet is the proven step up: an established medicine, a provider in the loop, and a dose matched to your body instead of a one-size-fits-all supplement.

How it works

How does sildenafil work?

It works by improving blood flow. Sildenafil blocks an enzyme called PDE5 so that, with natural arousal, blood vessels relax and more blood reaches the penis — making an erection easier to achieve and maintain.

I

Blocks PDE5

Sildenafil inhibits the PDE5 enzyme, which normally breaks down the signal that allows an erection to form.

II

Blood flows in

With PDE5 paused, blood vessels relax and circulation to the penis increases when you're aroused.

III

Firm & ready

The result is a firmer erection that's easier to achieve and maintain — with natural arousal still required.

Who it's for

Who is sildenafil for?

It's for men who want a proven, as-needed option for erectile dysfunction — especially those trying treatment for the first time.

Trouble getting or keeping an erection

If erections have become harder to achieve or maintain, sildenafil is a clinically established first step.

You want an as-needed, proven option

Taken only when you need it — no daily pill — ideal for spontaneity and trying treatment on your own terms.

Trying ED treatment for the first time

Affordable, well-understood, and flexible across three dose strengths — the sensible place most men start.

You want a discreet, online path

A private online visit and unmarked shipping mean no waiting room and no pharmacy counter.

When it's not the right fit

If you take nitrate medications for chest pain or heart conditions, sildenafil is not safe for you. If you'd prefer a longer window of effect, Tadalafil (up to 36 hours) may fit better. And any chest pain, fainting, or undiagnosed heart symptoms need evaluation before starting — mention them in your visit.

How to get it

How do I get sildenafil online?

You complete a private online visit, a licensed provider reviews it, and — if appropriate — your prescription ships to your door. No insurance required, no in-person appointment, no waiting room.

Complete your online visit

A few private questions about your health and goals, on your own time.

Provider review

A provider licensed in your state reviews your information and, if appropriate, prescribes the dose that fits you.

Discreet delivery

Shipped from a U.S. pharmacy in plain, unmarked packaging to all 50 states. Automatic refills available, and you can message your care team anytime.

Pricing is shown at checkout — no insurance needed, no hidden fees.

Using it & safety

How do I take it, and is it safe?

You take one tablet as needed, about an hour before sexual activity, and your provider sets your starting dose. Sildenafil is well-studied and generally well-tolerated, but it must never be combined with nitrates.

How to take it

Onset
Typically begins working within 30–60 minutes of taking your dose.
Timing
Take roughly 1 hour before sexual activity for best results.
Frequency
Used as-needed — not a daily medication. One dose per day maximum.
With food
A heavy or high-fat meal may delay how quickly it works.
Stimulation
Natural sexual arousal is still required for it to work.
Doses
Available in 25 mg, 50 mg, and 100 mg — your provider selects your starting dose.
As-needed tabletOne dose/day maxProvider-set dose

Safety & side effects

⚠ Never combine with nitrates

Taking sildenafil with nitrate medications (often prescribed for chest pain or heart conditions) can cause a dangerous, life-threatening drop in blood pressure. Tell your provider about every medication you take.

Most side effects are mild and short-lived. Possible effects include:

  • Headache
  • Flushing
  • Nasal congestion
  • Indigestion or upset stomach
  • Temporary changes in vision (color tint, light sensitivity)

Seek immediate care for an erection lasting more than 4 hours (priapism) or sudden vision or hearing changes. Limit alcohol, and disclose all medications and conditions so a licensed provider can confirm sildenafil is appropriate for you.

Compare your options

Which ED treatment fits you?

A side-by-side look at the ED options available through ForbiddenRx. Your provider helps you choose what's right.

TreatmentWhat it isOnsetDurationFormRx required
Sildenafil
Popular
Generic Viagra®, a PDE5 inhibitor30–60 min4–6 hoursTabletYes
TadalafilGeneric Cialis®, longer-acting PDE530–60 minUp to 36 hoursTabletYes
3-in-1 Hard MintCompounded blend, dissolvable15–30 minVariesTroche / mintYes
Branded ViagraOriginal brand-name sildenafil30–60 min4–6 hoursTabletYes
Questions, answered

Sildenafil FAQ

Is sildenafil the same as Viagra?

Sildenafil is the active ingredient in Viagra®, available as an FDA-approved generic. It contains the identical active compound as the brand-name product at a lower cost.

How quickly does it work?

Most men find sildenafil begins working within 30–60 minutes. Taking it about an hour before activity, and avoiding heavy meals beforehand, can help. Natural sexual stimulation is still required.

Do I need a prescription?

Yes. Sildenafil is a prescription medication. After your online visit, a licensed provider reviews your information. A prescription is not guaranteed and is subject to provider review of your health history.

Which dose is right for me?

Sildenafil comes in 25 mg, 50 mg, and 100 mg. Your provider recommends a starting dose based on your intake form, and your plan can be adjusted over time based on how you respond.

What should I avoid while taking it?

Never take sildenafil with nitrate medications — the combination can cause a dangerous drop in blood pressure. Limit alcohol, and disclose all medications and conditions to your provider.

Is my visit private?

Yes. Your consultation is confidential, and medication ships in discreet, unmarked packaging. Your information is handled in accordance with applicable privacy standards.

Credibility you can verify

Care held to a higher standard

Licensed Providers

U.S. board-certified clinicians

U.S. Pharmacies

Licensed, verified dispensing partners

All 50 States

Nationwide telehealth coverage

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Ready when you are

Complete a quick online visit and a licensed provider takes it from there — reviewing your information and, if appropriate, shipping your sildenafil discreetly to your door.

Start your online visit →

  • Discreet, unmarked packaging
  • Automatic refills
  • Message your care team anytime
  • Licensed providers in all 50 states
Medically reviewed

Sources & references

Medically reviewed by ForbiddenRx Medical Affairs — Independent, licensed medical providers · Last reviewed July 2026. This page was written and is periodically reviewed for medical accuracy in line with clinical guidance followed by the independent, licensed medical providers in the ForbiddenRx network. It is provided for general educational purposes and is not a substitute for professional medical advice, diagnosis, or treatment. Always talk with a licensed provider about your individual health.

  1. U.S. Food & Drug Administration. Viagra (sildenafil citrate) prescribing information — Drugs@FDA.
  2. MedlinePlus. Sildenafil. U.S. National Library of Medicine.
  3. Goldstein I, et al. Oral Sildenafil in the Treatment of Erectile Dysfunction. New England Journal of Medicine, 1998;338:1397–1404.
  4. Burnett AL, et al. Erectile Dysfunction: AUA Guideline. Journal of Urology (American Urological Association), 2018.
  5. Hatzimouratidis K, et al. EAU Guidelines on Male Sexual Dysfunction. European Association of Urology, 2019.
For further reading

Clinical references

This page is educational and is not medical advice.