Sildenafil Tablet Strengths, and Why High-Strength Offers Are a Red Flag
There is no sildenafil 150mg tablet licensed in the UK. UK product information for sildenafil states plainly that the maximum recommended dose is 100mg.
That single fact settles the question, and it has a consequence worth being blunt about. A website offering sildenafil 150mg is offering a strength that is not licensed for UK supply, and the actual contents and regulatory status of the product cannot be assumed from the listing.
This page sets out which strengths are actually licensed, why a bigger number does not produce a bigger result, and what to do if you have already been sold one.
If you came here looking to buy sildenafil 150mg, the honest answer is no, and the reason is below rather than hidden behind a disclaimer.
Key things to know
- No sildenafil 150mg tablet is licensed in the UK. The maximum recommended dose is 100mg
- The licensed tablet strengths for erectile difficulty are 25mg, 50mg and 100mg
- A 20mg tablet exists but is licensed for a different condition entirely, not as a low-strength option
- Taking more sildenafil does not produce a stronger effect, and higher doses have been linked with more frequent and more severe adverse reactions
- The MHRA seized around 19.5 million doses of illegally traded erectile dysfunction pills between 2021 and 2025
- Strength is decided in a clinical assessment, never selected from a menu
- Sildenafil must not be taken with nitrate medicines or nitric oxide donors
- Treatment suitability depends on an individual clinical assessment
Which Strengths Are Licensed in the UK
Three tablet strengths are licensed for erectile difficulty in the UK: 25mg, 50mg and 100mg. Those are the strengths that appear among licensed UK sildenafil products, and no higher tablet strength does.
A licensed medicine is one the regulator has authorised for sale, having assessed its quality, safety and effectiveness. That authorisation is specific to a strength, so a strength that has not been licensed has no UK marketing authorisation for that product and indication.
The Highest Licensed Strength
The highest licensed tablet strength for erectile difficulty is 100mg, and the product information is explicit that it is the maximum recommended dose.
That is a ceiling rather than a target. It is not a dose that is appropriate for everyone.
The same product information sets a second limit that matters just as much: the maximum recommended frequency is once per day. Neither limit is something a supplier can extend by selling a bigger tablet.
The 20mg Tablet, and Why It Is Not a Low-Strength Option
A sildenafil 20mg tablet does exist in the UK, but it is licensed for pulmonary arterial hypertension rather than for erectile difficulty.
Pulmonary arterial hypertension raises blood pressure in the arteries of the lungs. The same active substance is used because relaxing those blood vessels lowers the pressure the right side of the heart works against. It is a different condition, a different licence and a different treatment plan.
So a 20mg tablet is not a gentler starting point for erectile difficulty, and it should not be sought as one. Which strength and product are appropriate is settled during a clinical assessment.
Is There a Sildenafil 150mg Tablet?
No. No sildenafil 150mg tablet is licensed in the UK for any indication.
The question usually comes from having seen one advertised. An advert is not evidence that a licensed product exists. It is evidence that somebody is selling something outside the licensed supply chain.
Because 150mg is not a UK-licensed strength, a product sold at that strength should not be treated as an approved higher-dose alternative. Its contents, quality and safety cannot be assumed from the label.
What Being Unlicensed Means
A UK licence covers a specific active substance at a specific strength in a specific pharmaceutical form, and the regulator has assessed those combinations. A 150mg tablet has not been through that process, so nothing is known about it in the way things are known about a licensed strength.
You cannot rely on the quality, safety or effectiveness assurances that apply to licensed products, because none of them have been established for it.
Why a Higher Number Is Not a Stronger Result
This is the misconception the whole 150mg market is built on, and there is documented evidence against it.
Sildenafil does not work by overwhelming the system. It inhibits an enzyme called phosphodiesterase type 5, which allows the smooth muscle in local blood vessels to relax so blood flows into the tissue more easily. It also only works when you are aroused.
Increasing the dose does not produce a proportionate increase in benefit, while adverse effects become more likely. The product information records that in single-dose volunteer studies at very high doses, the adverse reactions were the same kinds seen at lower doses, but they occurred more often and more severely.
The Safety Risk
Dose. Sildenafil lowers blood pressure. At licensed doses the mean maximum fall in supine systolic pressure was 8.4 mmHg, with 5.5 mmHg diastolic, which usually does not cause clinical effects. Higher doses increase exposure, and with it the risk of adverse effects.
Interactions. The absolute exclusions do not soften at higher doses. They become more dangerous. Nitrates, nitric oxide donors, nicorandil, amyl nitrite and riociguat must never be combined with sildenafil at any strength.
What Is Actually Being Sold
Anyone offering to sell sildenafil 150mg is operating outside UK licensed supply, and the regulator has documented what that market contains.
Between 2021 and 2025, the Medicines and Healthcare products Regulatory Agency seized around 19.5 million doses of illegally traded erectile dysfunction pills, including 4.4 million in 2025 alone.
How Unlicensed Sellers Look
Sites offering high-strength sildenafil share a recognisable pattern:
- They offer a strength that is not licensed in the UK
- They ask no clinical questions, or use a form that cannot be failed
- They display no pharmacy registration number you can check
- They name no prescriber and no prescribing route
- They take payment through a messaging app or social media account
- They dispatch from outside the UK for a UK prescription-only medicine
The MHRA's position is direct: a medicine that does not come from a registered pharmacy is not safe, and supplying it that way is unlawful.
What Seized Products Contained
Seized products were found to contain the active ingredients sildenafil, tadalafil, vardenafil and avanafil, often undeclared.
The regulator warns that such products may contain no active ingredient, the wrong dose, hidden medicines or toxic ingredients, and can raise the risk of heart attack, stroke and dangerously low blood pressure. The risk is greatest for people with heart disease or high blood pressure, and those taking other medicines.
A 150mg label on its own cannot confirm the product's contents, strength or quality.
The Risks Together
| Risk | What it means in practice |
|---|---|
| Unknown contents | No active ingredient, the wrong amount, or a different substance |
| Unassessed dose | Above the maximum recommended dose, with no evidence of benefit |
| Missed contraindication | Nobody checked for nitrates, cardiovascular disease or blood pressure |
| No recourse | No registered pharmacy to contact, and no dispensing record |
The missed contraindication is the one that causes real harm. Somebody taking a nitrate for angina who buys an unlicensed high-strength tablet is combining two things that must never be combined, without knowing it.
If You Were Sold Sildenafil 150mg
This question usually comes after the purchase rather than before it. If that is you, here is the practical sequence:
- Do not take it. That applies even if you have already taken some without an obvious problem
- Keep the packaging. It helps anyone assessing what you were supplied
- Speak to a pharmacist or your GP, particularly if you take other medicines or have a heart condition
- Report it through the MHRA Yellow Card scheme, which accepts reports of suspected fake or defective medicines
- Do not reorder from that seller, and do not assume a different strength from them would be safer
If you have taken one and feel unwell, seek medical attention. Chest pain, fainting, a sudden decrease or loss of vision or hearing, or an erection lasting longer than four hours all need urgent attention. Tell whoever is treating you what you took, including that it came from an unverified source, because it changes what they need to consider.
If you were looking at 150mg because a licensed strength was not working, that is a clinical finding worth acting on properly. Report it to a prescriber rather than escalating on your own. Timing, food, alcohol and the underlying cause can all affect the response.
What Makes a Strength Safe
The safe strengths are the licensed ones, supplied by a registered pharmacy after a clinical assessment. In practice that means 25mg, 50mg or 100mg for erectile difficulty, at whichever strength has been prescribed for you.
Two things are required. The strength itself must be licensed, so its quality, safety and effectiveness have been assessed. And the supply must be assessed, so somebody has checked your medical history, your other medicines and the absolute exclusions before you take it.
A licensed strength bought without an assessment fails the second test. And an assessment cannot turn an unlicensed strength into a licensed medicine.
Which strength suits you depends on your medical history, your other medicines, and your kidney and liver function. Your prescriber will determine the appropriate treatment.
How to Check Before You Order
Run this on any supplier, including us, before placing an order.
- Check the strength is licensed. For erectile difficulty that means 25mg, 50mg or 100mg
- Find the GPhC registration number. A registered pharmacy displays it. Ours is 9012878
- Check that number against the register the regulator publishes
- Confirm the clinical assessment is real, meaning it could result in a refusal
- Identify the prescribing route, and confirm a UK registered prescriber reviews it
If a supplier is offering a 150mg sildenafil tablet, that is a clear reason to stop.
The full range of licensed options, including sildenafil tablets, is on the erectile dysfunction treatments page.
Safety Points That Apply at Every Strength
- Never take more than one tablet in any 24-hour period
- Never take two tablets of a lower strength to make up a higher one
- Never combine sildenafil with another medicine in the same class
- Sildenafil must not be taken with nitrates, nitric oxide donors, nicorandil, amyl nitrite or riociguat
- It may be unsuitable for people with significantly low or uncontrolled high blood pressure, so a healthcare professional should assess whether it is appropriate
- Stay with the strength and quantity on your dispensing label
Seek medical attention immediately for chest pain, fainting, an erection lasting longer than four hours, or a sudden decrease or loss of vision or hearing. If chest pain develops after taking sildenafil, tell whoever is treating you that you have taken it, and do not take a nitrate for that pain.
The product information also notes that it is important to have a check-up with a prescriber within the first six months of use, because erectile difficulty can be an early sign of circulatory disease. Results vary between individuals.
