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Numark Cold Sore Cream - Aciclovir

Numark Cold Sore Cream - Aciclovir

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  • ✔️ Targets herpes simplex virus to shorten cold sore outbreaks
  • ✔️ Works best when applied at first tingle or itch
  • ✔️ Clinically proven aciclovir 5% formula in every tube
  • ✔️ Suitable for adults and adolescents aged 12 and over
  • ✔️ Affordable own-brand alternative to Zovirax at just £4.49

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What Is Aciclovir Cold Sore Cream and How Can It Help?

 

Cold sores are one of those things that always seem to appear at the worst possible moment — before a big event, when you're run down, or right after a bout of illness. 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 cold sore cream is a clinically proven antiviral treatment that targets the virus directly, helping to shorten the duration of an outbreak and ease discomfort. Numark Cold Sore Cream contains aciclovir 5% w/w and is available over the counter without a prescription, making it easy to treat a cold sore quickly. You can find it alongside other creams and ointments at Cured Pharmacy.

Cold sores typically go through several stages — tingling, blistering, weeping, and crusting — and the earlier you start treatment, the better the outcome. The NHS advises that antiviral creams like aciclovir are most effective when applied at the very first sign of a cold sore, ideally during the tingling or itching phase before a blister even forms.

 

How Does Numark Cold Sore Cream Work?

 

Aciclovir belongs to a class of medicines called nucleoside analogues. It works by interfering with the herpes simplex virus's ability to replicate inside your skin cells. Here's how the process unfolds:

  • Aciclovir is absorbed into cells infected by the herpes simplex virus.
  • Inside infected cells, a viral enzyme called thymidine kinase converts aciclovir into its active form, aciclovir triphosphate.
  • Aciclovir triphosphate then blocks the viral enzyme DNA polymerase, which the virus needs to copy its DNA.
  • Without the ability to replicate, the virus cannot spread further, and the outbreak begins to resolve.

Because this activation process relies on a viral enzyme, aciclovir acts selectively on infected cells and has very little effect on healthy surrounding tissue. That's what makes it a well-tolerated topical treatment for most people.

 

Who Is Numark Cold Sore Cream Suitable For?

 

This cream is suitable for most adults and young people aged 12 and over who experience recurrent cold sores on the lips or face. It is an over-the-counter medicine, so you don't need a prescription to buy it. That said, it's not appropriate for everyone. It is suitable for:

  • Adults and adolescents aged 12 years and over
  • People experiencing the early signs of a cold sore (tingling, itching, or redness)
  • Those with recurrent herpes labialis (cold sores on the lips or around the mouth)
  • People looking for a cost-effective alternative to branded aciclovir creams

It is not suitable for use on genital herpes, inside the mouth, near the eyes, or on mucous membranes. If you're unsure whether this product is right for you, speak to a pharmacist before use.

 

How Does Numark Cold Sore Cream Compare to Other Cold Sore Treatments?

 

Feature Numark Aciclovir Cold Sore Cream Zovirax Cold Sore Cream
Active ingredient Aciclovir 5% Aciclovir 5%
Prescription required No (OTC) No (OTC)
Typical price £4.49 £6.00–£8.00+
Application frequency 5 times daily for 5 days 5 times daily for 5 days

 

Is Numark Cold Sore Cream Safe to Store and Use Long Term?

 

Numark Cold Sore Cream should be stored below 25°C, away from direct heat and sunlight, and kept out of the reach of children. Do not use the cream after the expiry date printed on the packaging. Once opened, the tube should be used within the period indicated on the label. If you experience frequent cold sore outbreaks — more than six per year — it's worth speaking to your GP, as oral antiviral therapy may be more appropriate for suppressive treatment. For everyday skin health between outbreaks, you might also find useful products in our skin care collection.

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.

Numark Cold Sore Cream - Aciclovir specifications
Treatment category Antiviral / Cold sore treatment
Active ingredient Aciclovir 5% w/w
Mechanism of action Inhibits herpes simplex virus DNA polymerase, preventing viral replication
Effective against Herpes simplex virus type 1 (HSV-1) — cold sores on lips and face
Suitable for Adults and adolescents aged 12 years and over
Strengths 5% w/w
Preparation Topical cream
Route of administration Topical (skin surface only)
UK classification Pharmacy (P) medicine
Drug class Nucleoside analogue antiviral
Pack size 2g tube

Specifications of Numark Cold Sore Cream - Aciclovir

 

What Is Numark Cold Sore Cream and What Is It Used For?

 

Numark Cold Sore Cream is a topical antiviral medicine containing aciclovir 5% w/w. It is used to treat cold sores — small, fluid-filled blisters that typically appear on or around the lips and are caused by the herpes simplex virus (HSV-1). Cold sores are extremely common in the UK; the NHS estimates that around two-thirds of people under 50 carry the virus, though not everyone develops visible sores. The cream does not cure the underlying viral infection, but it can significantly reduce the severity and duration of an outbreak, particularly when applied early. It is classified as a Pharmacy (P) medicine and is available without a prescription from registered pharmacies.

 

What Do You Need to Know Before Using Numark Cold Sore Cream?

 

Before applying this cream, read the following carefully. There are situations where this product may not be appropriate for you.

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 under 12 years of age — use only under medical supervision
  • Have cold sores inside the mouth, near the eyes, or on the genitals — this cream is not suitable for those areas

Warnings and precautions:

  • Avoid contact with eyes, mouth, and mucous membranes
  • Do not apply to broken or inflamed skin beyond the cold sore itself
  • If you are pregnant or breastfeeding, consult your doctor or pharmacist before use
  • Cold sores are contagious — avoid kissing or sharing utensils during an outbreak
  • If your cold sore has not improved after 10 days, see your GP

Drug interactions:

  • No clinically significant interactions are known at topical doses
  • If you are taking oral antiviral medicines, inform your pharmacist before using this cream

 

How Should You Use Numark Cold Sore Cream?

 

Timing is everything with cold sore treatment. Apply the cream as soon as you notice the first warning signs — tingling, itching, or redness — before a blister has fully formed. This gives the aciclovir the best chance of limiting the outbreak. If you're also managing other skin concerns, our first aid collection has a range of products that may help with minor skin irritation.

  1. Wash your hands thoroughly before and after applying the cream.
  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 — do not rub vigorously.
  4. Apply five times a day, approximately every four hours (you may skip the night-time dose if needed).
  5. Continue treatment for five days. If the sore has not healed, continue for up to ten days.
  6. Do not cover the treated area with a plaster or dressing unless advised by a healthcare professional.
Indication Age Group Dose Frequency
Cold sore (herpes labialis) Adults and adolescents (12+) Small amount applied to affected area 5 times daily for 5–10 days
Cold sore (herpes labialis) Under 12 years Not recommended without medical advice

 

What Are the Possible Side Effects of Numark Cold Sore Cream?

 

Like all medicines, Numark Cold Sore 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 or tingling of the skin
  • Temporary skin dryness or flaking

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

  • Skin redness or mild rash around the treated area
  • Contact dermatitis (allergic skin reaction) — stop use and seek advice if this occurs
  • Swelling or peeling of the skin

If you experience a severe allergic reaction — including swelling of the face, lips, or throat, difficulty breathing, or widespread rash — stop using the cream immediately and seek emergency medical attention. This type of reaction is rare but serious.

 

How Should You Store Numark Cold Sore Cream?

 

Correct storage helps maintain the effectiveness of the cream throughout its shelf life. Follow these guidelines:

  • Store below 25°C in a cool, dry place
  • Do not refrigerate or freeze
  • 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 and carton
  • Do not dispose of medicines via wastewater or household waste — return unused medicines to your pharmacy

If you're looking for other treatments to support your health during a cold sore outbreak — such as immune-supporting supplements — browse our vitamins and supplements range for options that may help support general wellbeing.

Written and reviewed by our qualified team

Your safety and success are our highest priorities. Our medical team rigorously evaluates every product and piece of advice we provide, ensuring you receive only the most effective, science-backed solutions available.

Frequently Asked Questions

Where can I buy Numark Aciclovir Cold Sore Cream online in the UK?

You can buy Numark Aciclovir Cold Sore Cream directly from Cured Pharmacy, a GPhC-registered UK online pharmacy, for just £4.49. It is available without a prescription as an over-the-counter Pharmacy (P) medicine. Simply add it to your basket and it will be dispatched promptly to your door.

How does aciclovir cold sore cream work in the body?

Aciclovir is a nucleoside analogue antiviral that is selectively activated inside cells infected by the herpes simplex virus. Once activated by a viral enzyme called thymidine kinase, it blocks the virus's DNA polymerase, stopping it from replicating. This limits the spread of the virus and helps the cold sore heal more quickly.

How do I apply Numark Cold Sore Cream step by step?

Wash your hands before and after application. Apply a small amount of cream to the cold sore and the area immediately surrounding it using a clean fingertip or cotton bud. Repeat five times a day, roughly every four hours, for five days — or up to ten days if the sore has not fully healed.

When is the best time to start using aciclovir cold sore cream?

The earlier you start, the better. Apply the cream at the very first sign of a cold sore — typically a tingling, itching, or burning sensation — before a blister has formed. Starting treatment during this prodromal phase gives aciclovir the best chance of reducing the severity and duration of the outbreak. Waiting until a blister is fully developed reduces its effectiveness.

How long does it take for aciclovir cold sore cream to work?

Most people notice improvement within five days of starting treatment, particularly if the cream is applied early. Some outbreaks may take up to ten days to fully resolve. If your cold sore has not improved after ten days of consistent use, you should see your GP, as a different treatment approach may be needed.

What are the side effects of Numark Cold Sore Cream?

The most common side effects are mild and localised, including a brief burning or stinging sensation, itching, and skin dryness at the application site. Less commonly, some people experience a mild rash or contact dermatitis. If you develop signs of a severe allergic reaction — such as facial swelling or difficulty breathing — stop use immediately and seek emergency medical help.

How do I manage side effects of Numark Cold Sore Cream?

Mild stinging or dryness usually settles on its own and does not require you to stop treatment. If skin irritation is bothersome, try applying the cream with a cotton bud rather than your fingertip to reduce friction. If you develop a rash or signs of an allergic reaction, discontinue use and speak to your pharmacist or GP promptly.

Who is eligible to use Numark Cold Sore Cream?

This cream is suitable for adults and adolescents aged 12 years and over who have cold sores on the lips or face caused by the herpes simplex virus. It is not suitable for children under 12 without medical supervision, and it should not be used on genital herpes, inside the mouth, or near the eyes. People with severely weakened immune systems should seek medical advice before use.

Can I use Numark Cold Sore Cream if I am pregnant or breastfeeding?

If you are pregnant or breastfeeding, you should speak to your doctor or pharmacist before using aciclovir cold sore cream. Although topical absorption into the bloodstream is minimal, it is always best to seek professional guidance during pregnancy and breastfeeding before using any medicine, even one applied to the skin.

What happens if I miss a dose of Numark Cold Sore Cream?

If you forget to apply the cream at one of your scheduled times, apply it as soon as you remember and then continue with your regular schedule. Do not apply a double amount to make up for a missed application. Consistency is important — try to apply the cream five times throughout the day at roughly equal intervals.

Is Numark Aciclovir Cold Sore Cream the same as Zovirax?

Yes, both products contain the same active ingredient — aciclovir 5% w/w — and work in exactly the same way. Numark is a pharmacy own-brand alternative to Zovirax that offers identical clinical efficacy at a significantly lower price point. The main difference is the brand name and packaging, not the medicine itself.

Can children use Numark Cold Sore Cream?

Numark Cold Sore Cream is not recommended for children under 12 years of age without medical advice. If your child develops a cold sore, speak to a pharmacist or GP before applying any antiviral cream. For general guidance on children's health products, you may find our baby and toddler collection a useful starting point for age-appropriate options.

What are the alternatives to aciclovir cold sore cream?

Alternatives include other topical antivirals such as penciclovir cream (Vectavir), which is applied every two hours while awake. For people with frequent or severe outbreaks, a GP may prescribe oral aciclovir or valaciclovir as suppressive therapy. Non-antiviral options such as cold sore patches or lip balms with SPF can help protect the area but do not treat the virus itself.

How long can you use aciclovir cold sore cream for?

Each course of treatment should last five days, extended to a maximum of ten days if the cold sore has not fully healed. This cream is intended for episodic treatment of individual outbreaks, not for continuous long-term use. If you experience more than six cold sore outbreaks per year, speak to your GP about whether suppressive antiviral therapy might be appropriate for you.

What does the latest research say about aciclovir for cold sores?

Aciclovir has been used clinically for decades and remains a well-established first-line treatment for herpes simplex infections. Published clinical evidence consistently shows that topical aciclovir, when applied early, reduces the duration of cold sore episodes and associated pain. The NHS and BNF continue to recommend it as an effective over-the-counter option for recurrent herpes labialis. For broader skin health support between outbreaks, explore our skin care collection.

How Should You Use Numark Cold Sore Cream?

Using this cream correctly makes a real difference to how quickly your cold sore heals. Always wash your hands thoroughly before and after applying the cream to avoid spreading the virus to other areas or to other people. Use a clean fingertip or a cotton bud to apply the cream — this also helps to minimise irritation to the already-sensitive skin around the sore.

What Is the Correct Dose of Numark Cold Sore Cream?

The dose is the same for all eligible users — a small amount applied to the affected area five times daily. There is no need to apply a thick layer; a thin, even coating is sufficient for the aciclovir to be absorbed into the skin. Do not apply more frequently than directed, as this will not speed up healing and may increase the risk of skin irritation.

When Is the Best Time to Use Numark Cold Sore Cream?

Timing your applications evenly throughout the day is important. A practical schedule might be: morning, mid-morning, lunchtime, late afternoon, and early evening — giving roughly four-hour gaps between each application. You do not need to set an alarm to apply the cream overnight; missing the night-time application will not significantly affect the outcome as long as you maintain the five daytime doses consistently.

Most importantly, start treatment at the very first sign of a cold sore. The tingling or itching sensation that precedes a blister is your cue to begin. Acting quickly during this prodromal stage gives the aciclovir the best opportunity to limit viral replication before the blister fully develops.

How Long Can You Use Numark Cold Sore Cream For?

The standard treatment course is five days. If your cold sore has not healed after five days, you may continue applying the cream for up to ten days in total. Do not use the cream for longer than ten days without seeking medical advice. This product is intended for episodic treatment of individual outbreaks — it is not designed for continuous daily use as a preventative measure. If you find yourself reaching for cold sore cream more than six times a year, it is worth speaking to your GP about whether a suppressive oral antiviral regimen might be more suitable for you.

Do not exceed the recommended dose. If in doubt, speak to your pharmacist.

What Are the Most Common Side Effects of Numark Cold Sore Cream?

Most people tolerate Numark Cold Sore Cream well, and side effects — when they do occur — are usually mild and confined to the area where the cream has been applied. Because the aciclovir is absorbed locally rather than into the bloodstream in significant amounts, systemic side effects are very unlikely at topical doses.

  • Mild burning or stinging sensation immediately after application
  • Itching or tingling of the skin around the cold sore
  • Temporary dryness or flaking of the treated skin
  • Slight redness at the application site

What Are the Less Common Side Effects of Numark Cold Sore Cream?

Less commonly, some people experience a more noticeable skin reaction. These effects are still generally mild but may be uncomfortable enough to prompt you to seek advice from a pharmacist.

  • Contact dermatitis — an allergic skin reaction causing redness, swelling, and intense itching
  • Skin peeling or crusting beyond the normal cold sore healing process
  • A localised rash around the treated area
  • Swelling of the skin at or near the application site

If you suspect you are having an allergic reaction to the cream rather than a normal skin response, stop using it and speak to your pharmacist. They can help you identify whether the reaction is related to the aciclovir itself or to one of the excipients, such as propylene glycol.

What Are the Serious Side Effects of Numark Cold Sore Cream?

Serious side effects from topical aciclovir are rare. However, a severe allergic reaction (anaphylaxis) is possible with any medicine, even one applied to the skin. Seek emergency medical attention immediately if you experience any of the following after applying this cream:

  • Swelling of the face, lips, tongue, or throat
  • Difficulty breathing or swallowing
  • A widespread skin rash or hives spreading beyond the application site
  • Dizziness, rapid heartbeat, or feeling faint

What Should You Do If You Experience Side Effects?

For mild side effects such as stinging or dryness, you generally do not need to stop treatment. Try applying the cream with a cotton bud rather than your fingertip to reduce friction, and use only the smallest amount needed to cover the affected area. If irritation persists or worsens, stop using the cream and consult your pharmacist. Do not apply any other creams, moisturisers, or cosmetics on top of the aciclovir cream without checking with a healthcare professional first.

If you experience a serious reaction, call 999 or go to your nearest A&E department immediately. Always report suspected side effects to the MHRA via the Yellow Card scheme at yellowcard.mhra.gov.uk.

Can Numark Cold Sore Cream Interact With Other Medicines?

At topical doses, aciclovir cold sore cream is not known to interact significantly with other medicines. Because very little of the active ingredient is absorbed into the bloodstream through the skin, the risk of systemic drug interactions is extremely low. However, if you are already taking oral antiviral medicines — such as oral aciclovir, valaciclovir, or famciclovir — inform your pharmacist before using this cream as well. People who are immunocompromised or taking immunosuppressant medicines should always seek medical advice before starting any antiviral treatment, even a topical one.

If you are concerned about any side effects, contact your pharmacist or GP immediately.

Patient Information Leaflet

Important - Before taking any medication, it is always important to read the Patient Information Leaflet (PIL)

Written and reviewed by our qualified team

GPhC Number: 2233073
Tarun Kumar

Reviewed by:

Tarun Kumar

Superintendent/ Clinical Lead

📖 Find out more about our team of medical content authors and how we ensure the accuracy of our content with our content guidelines.

Content last updated: 31 Mar 2025

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