Generic Viagra (Sildenafil): Does It Work, Is It Safe and How to Take It
Last updated: November 2026
Short answer: yes, there is a generic Viagra, and it works the same way as the brand. Generic Viagra is sildenafil citrate, the exact active ingredient in Pfizer’s blue pill. Generic versions have been sold in the US since December 2017 and cost a fraction of the brand price. This guide explains how well it works, how to take it, who should not take it, and how to buy it safely.
Key facts at a glance
- Generic name: sildenafil (as sildenafil citrate)
- Brand it copies: Viagra (Pfizer, approved in the US in 1998)
- Strengths: 25 mg, 50 mg and 100 mg tablets; 50 mg is the usual starting dose
- When to take it: about 1 hour before sex (it can work from 30 minutes up to 4 hours)
- How often: no more than once a day
- Never combine with: nitrate medicines (for example, for angina) or “poppers”
What is generic Viagra?
Viagra is Pfizer’s brand name for sildenafil citrate, a medicine for erectile dysfunction (ED). Once Pfizer’s patent protection ended, other companies were allowed to make the same medicine. In the US, Teva launched the first generic version on 11 December 2017, and many manufacturers now make it.
A generic medicine has to contain the same active ingredient, in the same strength and the same form (here, a tablet taken by mouth), as the brand. What can differ is the inactive ingredients, so the colour, shape and size of the tablet are often different from the blue diamond-shaped Viagra pill. The tablet is usually just labelled sildenafil or sildenafil citrate.
Outside the US, sildenafil is also sold under many other brand names. Indian manufacturers, for example, make it as Cenforce, Fildena, Caverta and Sildigra. These contain the same active ingredient; they are Indian generic versions and are not themselves FDA-approved products.
Does generic Viagra work?
Yes. Because it contains the same active ingredient, generic sildenafil works in the same way as Viagra. Generic medicines approved in the US must also show they are bioequivalent to the brand: in studies, the amount of medicine that reaches the blood, and how fast, has to closely match the original.
How well does sildenafil itself work? In the clinical studies behind Viagra’s US label, men with ED were asked whether the treatment improved their erections:
- 63% said yes on 25 mg,
- 74% on 50 mg,
- 82% on 100 mg,
- compared with 24% on a placebo (dummy pill).
Two things matter for it to work well:
- You still need sexual arousal. Sildenafil is not an aphrodisiac and does not cause an erection by itself; it makes it easier to get and keep one when you are aroused.
- Give it a few tries. It does not always work the first time. Anxiety, a heavy meal or alcohol can all get in the way. If it still does not help after several attempts, a doctor can review the dose or suggest another option.
How does sildenafil work?
Sildenafil belongs to a group of medicines called PDE5 inhibitors. During arousal, the body releases nitric oxide, which relaxes the blood vessels in the penis so more blood can flow in. An enzyme called PDE5 normally switches this effect off. Sildenafil blocks that enzyme for a few hours, so the blood vessels stay relaxed and an erection is easier to achieve and maintain. Other PDE5 inhibitors include tadalafil (Cialis), vardenafil (Levitra) and avanafil (Stendra/Spedra).
Generic Viagra vs Viagra
| Viagra (brand) | Generic Viagra (sildenafil) | |
|---|---|---|
| Active ingredient | Sildenafil citrate | Sildenafil citrate |
| Strengths | 25, 50, 100 mg | 25, 50, 100 mg (some brands abroad also sell other strengths) |
| How it works | PDE5 inhibitor | Same |
| Starts working | 30–60 minutes | Same |
| Effect lasts | About 4–5 hours | Same |
| Side effects | Headache, flushing, indigestion, stuffy nose | Same |
| Looks like | Blue, diamond-shaped | Varies by manufacturer |
| Price | Highest | Much lower |
Some men say the brand works better for them. Since the active ingredient is the same, any difference usually comes down to expectations, timing or circumstances rather than the medicine itself.
How to take generic Viagra
- Dose: most men start with 50 mg. Depending on how well it works and how well you tolerate it, a doctor may increase it to 100 mg or lower it to 25 mg.
- Timing: take it about 1 hour before sex. It can work from about 30 minutes up to 4 hours after you take it.
- Food: you can take it with or without food, but a heavy or high-fat meal can delay its effect.
- Alcohol: a small amount is usually fine, but heavy drinking makes erections harder and can increase dizziness.
- Grapefruit: avoid grapefruit and grapefruit juice; they can raise sildenafil levels and side effects.
- Frequency: no more than one dose in 24 hours.
About higher strengths: 100 mg is the highest dose approved for ED. Some brands sold abroad come in 120, 150 or 200 mg tablets, which is above the maximum dose studied. Higher doses mainly increase side effects, so do not take more than 100 mg in a day unless a doctor has told you to.
The 25 mg starting dose is often recommended for men over 65, men with liver or severe kidney problems, and men taking certain other medicines (see below). Sildenafil is also sold as a 20 mg tablet (brand name Revatio) for a lung condition called pulmonary arterial hypertension; that is a different use and dosing.
Is generic Viagra safe?
Sildenafil has been used by millions of men since 1998 and is safe for most healthy adults when taken correctly. Side effects are usually mild and pass within a few hours.
Common side effects
- Headache
- Facial flushing
- Indigestion
- Blocked or runny nose
- Dizziness
- Changes in vision, such as a blue tint or sensitivity to light
- Back pain or muscle aches
Get medical help straight away if you have
- An erection lasting longer than 4 hours (priapism), which can permanently damage the penis
- Sudden loss or reduction of vision in one or both eyes
- Sudden decrease or loss of hearing, or ringing in the ears
- Chest pain, fainting or a fast or irregular heartbeat during or after sex
- Signs of a serious allergic reaction, such as swelling of the face, lips or throat
Do not take sildenafil if you
- Take any nitrate medicine, such as glyceryl trinitrate (GTN), isosorbide mononitrate or isosorbide dinitrate for angina, or use “poppers” (amyl or butyl nitrite). The combination can cause a dangerous drop in blood pressure.
- Take riociguat (Adempas), a medicine for pulmonary hypertension.
- Have been told by a doctor that sexual activity is unsafe for your heart, or have recently had a heart attack or stroke.
- Have very low blood pressure, severe liver disease, or an inherited eye condition called retinitis pigmentosa.
- Have ever lost vision because of reduced blood flow to the optic nerve (NAION).
Medicines that need care
- Alpha-blockers (for example doxazosin or tamsulosin, used for blood pressure or prostate symptoms): start with 25 mg and only when your alpha-blocker dose is stable.
- Some HIV medicines and antifungals, such as ritonavir, ketoconazole or itraconazole, which can greatly increase sildenafil levels.
- Other ED treatments: do not combine sildenafil with tadalafil, vardenafil or other PDE5 inhibitors.
Erectile dysfunction can be an early sign of heart disease, diabetes or high blood pressure. If you have not been checked, it is worth seeing a doctor before you start treatment.
Is generic Viagra legal?
Yes. Generic sildenafil is a legal, licensed medicine. In the US it needs a prescription. In the UK, a 50 mg sildenafil product (Viagra Connect) has been available from pharmacists without a prescription since 2018, after a short consultation, while other strengths still need a prescription. Rules about ordering medicines from another country differ from place to place, so check the regulations where you live.
How to buy generic Viagra safely
Counterfeit ED pills and “herbal Viagra” supplements are common. The FDA has repeatedly warned about supplements sold as natural sexual enhancers that secretly contain sildenafil or similar drugs in unknown amounts. To stay safe:
- Choose a pharmacy that tells you the manufacturer, strength and active ingredient of every product.
- Expect to be asked about your health and the medicines you take; a seller that asks nothing is a warning sign.
- Avoid “natural” or “herbal” products that promise Viagra-like effects.
- Check the tablets and packaging when they arrive, and keep the leaflet.
Generic sildenafil at Safe Generic Pharmacy
We stock several sildenafil brands made by established manufacturers. Each product page lists the manufacturer and strength:
- Sildenafil Citrate 100 mg
- Lovento (sildenafil 100 mg)
- Fildena 100
- Cenforce 100
- Caverta 100
- Sildigra 100
See all options in our erectile dysfunction medicines range.
Frequently asked questions
Is generic Viagra as good as Viagra?
Yes. It contains the same active ingredient in the same strength and works in the same way. Most men notice no difference apart from the price and the look of the tablet.
What is the generic name for Viagra?
Sildenafil (sildenafil citrate). Tablets are usually labelled “sildenafil” followed by the strength, for example “sildenafil 50 mg”.
How long does generic Viagra last?
The effect usually lasts about 4 to 5 hours. That does not mean a 4-hour erection: it means you can get an erection more easily when aroused during that time. The erection normally goes down after ejaculation, as usual.
Does generic Viagra increase sex drive?
No. Sildenafil helps blood flow to the penis but does not increase desire or libido, and it does not change testosterone levels.
Can I take generic Viagra every day?
You can take it once a day if needed, but it is designed to be taken “on demand” before sex. If you want a daily option, ask a doctor about low-dose daily tadalafil.
Can I take ibuprofen with sildenafil?
Standard drug-interaction references do not list an interaction between sildenafil and ibuprofen, but check with a pharmacist if you take any other medicines or have stomach, kidney or heart problems.
Can women take generic Viagra?
Sildenafil is not approved for women. Studies of sildenafil for low sexual desire in women did not show a clear benefit.
Does generic Viagra cure erectile dysfunction?
No. It treats the symptom for a few hours at a time but does not fix the underlying cause. Losing weight, stopping smoking, exercising, drinking less and treating conditions such as diabetes or high blood pressure can improve erections over time.
Related guides
- Which erectile dysfunction pill is best?
- Generic Cialis (tadalafil) explained
- What is the safest drug for erectile dysfunction?
- Signs and causes of erectile dysfunction
Sources
- Pfizer. Viagra (sildenafil citrate) US prescribing information.
- NHS. Sildenafil (Viagra).
- Pharmacy Times. FDA approves first generic version of Viagra.
- British Association of Urological Surgeons. Sildenafil patient information.
This article is for general information and does not replace advice from a doctor or pharmacist. Always read the leaflet that comes with your medicine, and talk to a healthcare professional before starting sildenafil, especially if you have a heart condition or take other medicines.
