This question does not have a simple winner.
Aciclovir cream and aciclovir tablets contain the same active ingredient and work against herpes simplex virus in a similar way. However, they are used in different situations, and neither can simply be described as the stronger option for every cold sore.
For a typical cold sore on the lip or face, an antiviral cream can be bought from a pharmacy and may help shorten healing time when it is started early. Oral aciclovir is usually reserved for situations where a clinician thinks tablets are more appropriate, such as severe or widespread infections, recurrent problems or people with a weakened immune system.
The practical questions are therefore less about which one is stronger and more about when treatment is started, how severe the outbreak is, where the sore is, and whether you have any health conditions that affect treatment.
This page looks at how aciclovir cream and tablets work, how they compare, when timing matters, whether they can be used together, how aciclovir compares with penciclovir, and when it is worth speaking to a pharmacist or prescriber.
Key Things to Know
- Tablets and cream contain the same active ingredient, aciclovir, an antiviral medicine used for herpes simplex virus infections
- The main difference is how the medicine reaches the affected area: tablets are absorbed into the body, while cream is applied directly to the skin
- The benefit of antiviral treatment for an ordinary cold sore is generally modest, particularly if treatment is started after the early stage
- Starting a cold sore cream when you first notice tingling or itching gives it the best chance of helping
- Aciclovir cream for cold sores can be bought from pharmacies, while aciclovir tablets are prescription medicines for this use
The Honest Answer: Neither Is Established as Better for Every Cold Sore
What the Research Actually Shows
For an uncomplicated cold sore, the benefit from antiviral treatment is usually modest. Cold sores normally clear on their own, often within around 10 days, and antiviral creams may help shorten the healing time when they are used early.
It is harder to make a simple cream versus tablet comparison. Oral aciclovir is not routinely used for ordinary cold sores in the same way as topical antiviral cream. NHS guidance says a GP may prescribe antiviral tablets when cold sores are very large, painful or keep coming back. They may also be considered when someone has a weakened immune system.
So it would be misleading to say that tablets are always more effective than cream. The treatment chosen depends on the type and severity of the outbreak and the person's circumstances.
The important point is that a tablet is not simply a stronger version of the cream. It is the same active ingredient delivered in a different way and used for different clinical situations.
Why the Benefit Can Be Modest
Cold sores are caused by herpes simplex virus and usually get better without antiviral treatment. That means an antiviral is being used to help shorten or control an outbreak that would usually settle on its own.
Timing also matters.
A cold sore often starts with tingling, itching or burning before the blister appears. NHS guidance recommends using antiviral cream as soon as these early symptoms are recognised because treatment is less likely to help once the outbreak is well established.
Aciclovir works by interfering with the virus's ability to make more viral DNA. It therefore has more opportunity to act while the virus is actively multiplying.
This does not mean that applying cream after a blister appears is completely pointless. Some product information allows treatment to start during the blister stage. However, the best chance of benefit comes from starting as early as possible.
How Each One Works
| Point | Aciclovir tablets | Aciclovir 5% cream |
|---|---|---|
| Route | Swallowed and absorbed into the body | Applied directly to the affected skin |
| Active ingredient | Aciclovir | Aciclovir |
| Mechanism | Aciclovir interferes with herpes simplex virus replication | Aciclovir interferes with herpes simplex virus replication at the treated area |
| Availability | Prescription medicine | Available from pharmacies for cold sores |
| Typical use | More severe or recurrent infections, or situations where a clinician considers oral treatment appropriate | Cold sores on the lips and face |
| How it is used | Follow the dose and schedule prescribed | Usually applied 5 times a day, with around 4 hours between applications |
| Common side effects | Headache, dizziness, nausea, vomiting and diarrhoea can occur | Mild burning, stinging or irritation can occur |
| Main practical advantage | Treats infection from inside the body and may be appropriate when cream is not enough | Can be started quickly at home when early cold sore symptoms appear |
The important difference is therefore the route of treatment, not the idea that one is simply a stronger version of the other.
Aciclovir cream should not be used inside the mouth or nose, in or near the eyes, or on other areas unless the product specifically says it is suitable. NHS guidance also advises people with a severe cold sore or a weakened immune system to seek medical advice rather than relying on cold sore cream alone.
Do Cold Sore Tablets Work?
Aciclovir tablets can be used to treat herpes simplex infections, including cold sores, but they are not routinely needed for an ordinary cold sore.
A GP may consider antiviral tablets when cold sores are very large, painful or keep coming back. Oral treatment can also be important for people with a weakened immune system, where herpes simplex infections may be more serious.
Aciclovir tablets are available in different strengths, including 200mg and 400mg. The correct strength and number of doses depend on why the medicine has been prescribed and your individual circumstances. You should follow the prescription rather than choosing a stronger tablet yourself.
It is also important to drink plenty of water while taking aciclovir tablets. This is particularly important if you have kidney problems, as the dose may need to be adjusted.
Does the Cream Work?
Yes, aciclovir cream can help with cold sores, particularly when it is started as soon as the first signs appear.
NHS guidance says antiviral creams can ease symptoms and speed up healing when used correctly. They are most useful when started at the early tingling or itching stage.
The main advantage is convenience. You can buy the cream from a pharmacy without a prescription and start using it when you recognise the early signs of a cold sore.
The limitation is that it is a topical treatment. It is intended for affected skin on the lips and face and should not be used inside the mouth or nose or in or near the eyes.
Standard aciclovir cold sore cream is usually applied 5 times a day, with around 4 hours between applications. Always follow the instructions for the specific product you have bought because the recommended course can vary between products.
The Thing That Actually Matters Most: Timing
If you regularly get cold sores, recognising the early signs can be useful.
A cold sore often starts with tingling, itching or burning before a blister appears. This is the point when an antiviral cream is most likely to help. NHS guidance specifically recommends starting treatment as soon as you recognise these early symptoms.
Once the blister is established, the benefit may be smaller. That is why having a suitable treatment available can be more useful than waiting several days before starting it.
However, do not assume that every tingling sensation is a cold sore. If you are not sure what the lesion is, a pharmacist or GP can help you work out whether antiviral treatment is appropriate.
Can You Use Aciclovir Cream and Tablets Together?
There are situations where a healthcare professional may prescribe oral aciclovir when someone is also using a topical treatment, but you should not automatically combine them yourself.
For a straightforward cold sore, there is no reason to assume that adding tablets to cream will produce a stronger or faster result. Oral aciclovir is generally considered when the outbreak or the person's health makes systemic treatment more appropriate.
If your cold sore is severe enough that you are considering both forms, speak to a pharmacist or prescriber first. They can decide whether tablets are needed rather than simply adding another form of the same medicine.
Branded and Generic Cold Sore Creams
You may see several aciclovir creams on a UK pharmacy shelf at different prices. This can make it difficult to tell whether the more expensive product is actually different.
If two products contain aciclovir 5% cream and are licensed for the same use, the active ingredient and strength are the same. The differences may include the brand, packaging, inactive ingredients and price.
For example, Zovirax is a branded aciclovir cold sore cream, while pharmacies may also sell generic or own label versions.
The important thing is to check the active ingredient and strength rather than judging the product by its name alone.
Two practical differences are worth checking:
- Pack size. Pharmacy products may be supplied in particular pack sizes, while larger or different presentations may require a prescription depending on the product
- The cream base. If a particular cream has caused irritation or stinging before, the inactive ingredients may be relevant, so a pharmacist can help you choose another suitable product
Cream or Ointment?
This is an easy place to get confused because aciclovir is available in more than one topical form.
For cold sores on the lips and face, aciclovir 5% cream is the relevant product. NHS guidance specifically lists aciclovir cream for cold sores on the lips and face.
Aciclovir eye ointment is a different product for herpes simplex infections of the eye. It is not a stronger version of cold sore cream and should not be substituted for it. Eye infections caused by herpes simplex need proper medical assessment because they can affect vision.
Do not put cold sore cream in or near your eyes, inside your mouth or inside your nose. Follow the instructions for the exact product you have.
If you have a sore close to the eye, eye pain, redness, light sensitivity or changes in your vision, seek medical advice promptly rather than treating it as an ordinary cold sore.
The Other Antiviral Cream You May See
Aciclovir is not the only antiviral treatment that you may come across when searching for cold sore treatment. Penciclovir 1% cream is another topical antiviral used for recurrent herpes labialis in some markets and products.
However, availability, age restrictions and dosing instructions depend on the specific UK licensed product. If you are considering penciclovir instead of aciclovir, check the current product information or ask a pharmacist rather than relying on information from another country.
For any topical antiviral, following the application schedule matters. Applying it occasionally when the instructions require regular use may reduce the chance of getting the intended benefit.
The main practical lesson is simple: choose a treatment that is suitable for your symptoms and that you can realistically use as directed.
Products You May Have Seen From Abroad
Search results can show cold sore products that are not routinely available in the UK.
Docosanol, for example, is an antiviral cold sore cream available in some countries, including the United States. It is not the same medicine as aciclovir.
If you are looking at a product bought from another country, check its active ingredient, strength and licensing status rather than assuming it is equivalent to a UK product.
Buying medicines from an unknown overseas website can also make it difficult to know whether the product is genuine, correctly stored or supplied with the right information.
For a UK cold sore, a pharmacist can advise you about the licensed treatments available locally.
So Which Should You Choose?
There is no single answer that works for everyone.
| Your situation | A practical option |
|---|---|
| A typical cold sore that you recognise early | Aciclovir 5% cream may be suitable |
| You have just noticed tingling or itching | Starting a suitable antiviral cream promptly may give it the best chance of helping |
| The cold sore is very large or painful | Speak to a GP or pharmacist because oral treatment may be considered |
| You keep getting cold sores | Speak to a healthcare professional about whether you need a different treatment approach |
| You have a weakened immune system | Get medical advice rather than relying on self treatment |
| The sore is near or affecting the eye | Seek medical advice promptly |
| You have kidney problems and are considering tablets | Speak to a prescriber because the oral dose may need to be adjusted |
The right treatment depends on the type of outbreak, your health and where the sore is located. A pharmacist can usually help with an uncomplicated cold sore, while more severe or recurrent infections may need medical assessment.
Access and Cost
Aciclovir cold sore cream can be bought from a pharmacy without a prescription. NHS guidance says antiviral creams can be purchased from pharmacies and may help speed up healing when used correctly and started early.
Aciclovir tablets are prescription medicines. They may be prescribed when a GP considers them appropriate, particularly for severe, painful or recurrent cold sores or for people with a weakened immune system.
For an uncomplicated cold sore, an NHS prescription is not usually needed for the cream because it is available to buy from a pharmacy. NHS England guidance also says infrequent cold sores of the lip should not routinely be treated with a prescription in primary care when suitable over the counter options are available.
If you are considering prescription treatment, an online consultation with a UK registered prescriber can be an option where the service is clinically appropriate. The prescriber should assess your symptoms and medical history before deciding whether treatment is suitable.
Medical Disclaimer
This article is provided for general information only and does not constitute medical advice. It does not tell you which form of aciclovir to use or what dose you should take.
If you are using aciclovir tablets, tell your prescriber about any kidney problems and any other medicines you take. Oral aciclovir may need particular care in people with kidney problems, and drinking plenty of water is important while taking the tablets.
For aciclovir cream, follow the instructions on the product packaging and do not apply it inside the mouth or nose, in or near the eyes, or to areas that the product does not cover.
Speak to a pharmacist or GP if your cold sore is very large or painful, has not started to heal within 10 days, keeps coming back, or you are not sure whether it is actually a cold sore. You should also seek medical advice if you have a weakened immune system.
If a cold sore affects your eye or you develop eye symptoms, seek medical advice promptly.
Do not increase the dose, use both forms or change treatment without appropriate advice. Suspected side effects can be reported through the MHRA Yellow Card Scheme.
