Aciclovir 5% Cream - 2g

Is Aciclovir Cream for Cold Sores Right for You?

Cold sores are one of those things that always seem to appear at the worst possible moment — before a big event, during a stressful week, or when you're already run down. They're caused by the herpes simplex virus type 1 (HSV-1), which lies dormant in nerve tissue and reactivates when your immune system is under pressure. Aciclovir cream for cold sores is a clinically established, over-the-counter antiviral treatment that can help shorten the duration of an outbreak and ease discomfort when applied early. You can browse our full range of creams and ointments if you're looking for other topical treatments alongside this one.

Aciclovir 5% Cream comes in a convenient 2g tube — compact enough to keep in your bag or desk drawer so you're ready the moment that familiar tingling starts. At just £5.19, it's an accessible option for managing cold sore outbreaks without needing a GP appointment.

How Does Aciclovir 5% Cream Work Against the Herpes Simplex Virus?

Aciclovir belongs to a class of medicines called antivirals. It doesn't cure the herpes simplex virus, but it does interfere with the virus's ability to reproduce — which is what causes the visible cold sore to develop and worsen. Here's how the mechanism works:

• Aciclovir is absorbed into cells infected by the herpes simplex virus.
• Inside those cells, a viral enzyme called thymidine kinase converts aciclovir into its active form, aciclovir triphosphate.
• This active form then blocks the viral enzyme DNA polymerase, which the virus needs to copy its genetic material.
• Without the ability to replicate, the virus cannot spread to surrounding skin cells, limiting the size and severity of the outbreak.

Because aciclovir targets a virus-specific enzyme, it has very little effect on healthy human cells — which is why it's well tolerated when used topically.

Who Is Aciclovir 5% Cream Suitable For?

This cream is suitable for most adults and young people who experience recurrent cold sores. It's particularly useful if you know your triggers — things like sun exposure, illness, or stress — and can apply the cream at the very first sign of an outbreak. The earlier you start, the better the results tend to be.

• Adults aged 18 and over with recurrent cold sores
• Young people aged 12 to 17 (under pharmacist guidance)
• People who want an over-the-counter option without a prescription
• Those who prefer a topical treatment rather than oral antiviral tablets

It is not suitable for use inside the mouth, nose, or eyes, and should not be applied to genital herpes. If you're unsure whether this product is right for you, speak to a pharmacist before purchasing.

How Does Aciclovir Cream Compare to Other Cold Sore Treatments?

How Should You Store Aciclovir 5% Cream?

Store your tube of aciclovir cream below 25°C, away from direct heat and sunlight. Keep it out of reach of children and do not use it after the expiry date printed on the packaging. Once opened, the cream should be used within the treatment course — do not share it with others, as cold sores are contagious. If you're managing other skin concerns at the same time, take a look at our skin care collection for complementary products.

This product is a medicine. Speak to your doctor or pharmacist before using if you have an underlying medical condition or are taking other medicines.

What Is Aciclovir 5% Cream and What Is It Used For?

Aciclovir 5% Cream is a topical antiviral medicine used to treat cold sores on the lips and face caused by the herpes simplex virus (HSV-1). It belongs to a group of medicines called nucleoside analogues, which work by interfering with viral replication. The cream is available over the counter in the UK as a Pharmacy (P) medicine, meaning you can buy it without a prescription from a registered pharmacy. It is intended for use on the skin only — not inside the mouth, nose, or on genital areas.

What Do You Need to Know Before Using Aciclovir 5% Cream?

Before applying this cream, read the following carefully. There are certain situations where you should not use it, or where you should seek advice first.

Do not use this cream if you:

• Are allergic to aciclovir, valaciclovir, propylene glycol, or any other ingredient in the cream
• Have a severely weakened immune system (e.g. due to HIV, chemotherapy, or organ transplant) — seek medical advice first
• Are applying it to the eyes, inside the mouth, or to genital sores
• Are under 12 years of age

Speak to your pharmacist or GP before using if you:

• Are pregnant or breastfeeding
• Have a history of kidney problems
• Have very frequent or unusually severe cold sore outbreaks
• Have a cold sore that has not improved after 10 days of treatment

Known drug interactions:

• No clinically significant interactions are known for topical aciclovir due to minimal systemic absorption
• If you are taking oral antiviral medicines, inform your pharmacist before using this cream

How Should You Use Aciclovir 5% Cream Correctly?

Timing is everything with cold sore treatment. Apply the cream as soon as you notice the first signs of a cold sore — tingling, itching, or redness — before a blister even forms. This is when the antiviral is most effective at limiting the outbreak.

1. Wash your hands thoroughly before and after application.
2. Using a clean fingertip or cotton bud, apply a thin layer of cream to the affected area.
3. Gently smooth the cream over the cold sore and the skin immediately surrounding it.
4. Apply five times a day, roughly every four hours during waking hours.
5. Do not apply at night — simply resume the next morning.
6. Avoid touching your eyes or other mucous membranes after applying.
7. Continue for five days. If the sore has not healed, continue for up to ten days.

If you're also dealing with other infections or skin concerns, our athletes foot and fungal infections collection has further topical treatment options worth exploring.

What Are the Possible Side Effects of Aciclovir 5% Cream?

Like all medicines, aciclovir cream can cause side effects, although not everyone experiences them. Most side effects are mild and localised to the area of application.

Common side effects (may affect up to 1 in 10 people):

• Mild burning or stinging sensation at the application site
• Itching around the treated area
• Temporary skin dryness or flaking

Less common side effects (may affect up to 1 in 100 people):

• Redness or mild skin irritation
• Contact dermatitis (allergic skin reaction)
• Swelling or peeling of the skin at the application site

Stop using the cream and seek medical advice if you develop signs of a serious allergic reaction, such as widespread rash, swelling of the face or throat, or difficulty breathing. These reactions are rare but require prompt attention.

How Should You Store Aciclovir 5% Cream?

• Store below 25°C in a cool, dry place
• Keep away from direct sunlight and heat sources
• Keep the tube tightly closed when not in use
• Keep out of the reach and sight of children
• Do not use after the expiry date printed on the tube or carton
• Do not share the tube with other people — cold sores are contagious
• Do not dispose of medicines via wastewater or household waste — return unused medicines to your pharmacy

If you're looking for other health essentials to keep at home, our first aid collection has a range of useful products for everyday health needs.