Is Valaciclovir Better Than Aciclovir for Cold Sores: Which Should You Choose?

Cold sores caused by the herpes simplex virus can be treated with either aciclovir or valaciclovir. If you are wondering whether valaciclovir is better than aciclovir, the short answer is no. Both treatments can be similarly effective when started early.

Both are antiviral medicines that work by stopping the virus from multiplying. Valaciclovir is absorbed more efficiently than aciclovir, with a bioavailability of around 54% compared with about 15 to 20% for aciclovir. This is why it can be taken as a shorter treatment course. In most cases, the main differences are convenience and cost rather than one medicine being more effective than the other.

If you are comparing treatment options through an online pharmacy such as EveryDayMeds or your usual prescriber, your choice will often come down to whether you prefer valaciclovir's one day treatment or aciclovir's multiple doses over five days. Below, we compare how they work, dosing, side effects, cost and convenience to help you understand the differences before speaking to a prescriber.

1. What Are Aciclovir and Valaciclovir? Understanding Their Role Against Herpes Simplex Virus

Aciclovir is the active antiviral medicine. Valaciclovir is a prodrug, which means it is converted into aciclovir after it is absorbed by the body. Both are antiviral medicines within the wider group of antimicrobial medicines.

Valaciclovir has a higher bioavailability than aciclovir, around 54% compared with approximately 15 to 20%. This allows effective levels of the medicine to be reached with fewer doses. Both medicines work in the same basic way by reducing viral DNA replication, helping to stop the virus from multiplying. Valaciclovir simply provides a more convenient way of delivering the same active medicine with fewer doses.

2. How the Dosing Actually Compares

This is often the biggest difference people want to understand, as the dosing schedules are quite different.

For cold sores, aciclovir is commonly prescribed as 200mg five times a day, or 400mg three times a day, usually for five days. These doses are generally spaced every three to four hours while you are awake.

Valaciclovir follows a different schedule. The licensed treatment for cold sores is 2g (2000mg) taken twice in one day, with the second dose taken around 12 hours after the first. No further doses are usually needed after that.

The main difference is convenience. Aciclovir requires several doses each day over five days, while valaciclovir only requires two doses in one day. Some people find the simpler schedule easier to follow. Both treatments can work well when started promptly, and the most suitable option depends on your individual circumstances and your prescriber's advice.

Always follow the dose and treatment duration recommended by your prescriber or shown in your patient information leaflet. Some people, including those with kidney disease or reduced kidney function, may need a different dose.

Quick answer for a rushed reader

Aciclovir: 200mg five times a day, or 400mg three times a day, usually for five days.

Valaciclovir: 2g twice in one day, with the doses taken around 12 hours apart.

Both treatments can be equally effective for cold sores when started early. The main difference is the treatment schedule, not how well they work.

3. Is Valaciclovir Better Than Aciclovir?

Not necessarily. When comparing valaciclovir and aciclovir, both treatments can be equally effective for cold sores when they are started at the first sign of symptoms, such as tingling or itching before a blister appears. They are both commonly used in clinical practice, and there is no strong evidence to suggest that one is generally more effective than the other for treating cold sores.

The biggest advantage of valaciclovir is convenience. It is taken over just one day, with fewer doses to remember. Some people find this easier to fit into their routine.

Aciclovir, on the other hand, is usually the lower cost option and has been used for many years. The best choice often depends on your preferences, your medical history, and what your prescriber feels is most suitable for you.

4. Cost Comparison: Aciclovir vs Valaciclovir

Aciclovir is generally the more affordable option, partly because it has been available for longer and is widely supplied as a generic medicine.

Valaciclovir usually costs more, although its treatment is completed in just one day. When comparing prices, it is worth considering the full treatment course rather than the pack price alone.

If cost is an important factor, your prescriber or pharmacist can help you understand which option may be the most suitable for your needs.

Current Indicative Pricing

Prices update live and may change. The live pricing shown during your consultation always takes precedence over this table.

5. Effectiveness: What the Evidence Shows

Both aciclovir and valaciclovir can help reduce how long a cold sore lasts and how severe symptoms feel, provided treatment is started early. Ideally, treatment should begin within the first day of noticing signs such as tingling, itching or burning, before a visible sore appears.

Starting treatment later, once a blister has fully developed, may reduce the benefit of either medicine.

It is important to remember that these antiviral medicines do not cure herpes or remove the underlying herpes simplex virus. Instead, they help manage individual cold sore outbreaks and may shorten symptoms when used promptly.

This comparison focuses on cold sores. When these medicines are used for shingles caused by the varicella zoster virus, valaciclovir may offer some advantages. A 2023 review suggested that valaciclovir may help shingles related pain settle more quickly than aciclovir, although treatment choice still depends on individual circumstances and prescriber advice.

6. Side Effects and Tolerability

Both medicines are generally well tolerated, and most people use them without significant problems.

When side effects occur, they are usually mild and may include:

• Headache
• Nausea
• Mild stomach upset

Less common side effects can differ slightly between the two medicines. Valaciclovir has been associated with dizziness and changes in liver blood test results, while aciclovir has occasionally been linked with muscle pain or changes in certain blood test results.

Aciclovir has a long history of use, and valaciclovir has a similar safety profile because it is converted into aciclovir after it is absorbed by the body.

People with reduced kidney function may need a different dose, particularly as valaciclovir is used in higher single doses for cold sore treatment. Staying well hydrated can also help support normal kidney function while taking antiviral medicines.

Always tell your prescriber or pharmacist about any other medicines, supplements or herbal products you take, as interactions can occur. Seek medical advice if you notice signs of an allergic reaction or have any symptoms that concern you.

7. Which Treatment Might Suit You?

This information is intended as general guidance rather than a recommendation. The most suitable treatment depends on an individual clinical assessment.

You may prefer aciclovir if:

• Cost is an important factor
• You do not mind taking tablets several times a day for five days
• You prefer a treatment with a long track record of use

You may prefer valaciclovir if:

• You would like a shorter treatment course
• Taking fewer doses is more convenient for your routine
• You are happy with a higher single dose taken over one day

If you experience frequent, severe or unusual cold sore outbreaks, or if you have a weakened immune system, it is important to discuss treatment options directly with your prescriber. Standard treatment plans may not be suitable for everyone.

8. Aciclovir Cream vs Tablets: A Related Question

Aciclovir is available in several forms, including tablets, cream and injectable treatments. Valaciclovir is usually supplied as tablets.

Aciclovir 5% cream is applied directly to the cold sore and may be a suitable option for mild or occasional outbreaks, especially for people who prefer not to take tablets.

Oral antiviral treatments, such as aciclovir tablets or valaciclovir tablets, work throughout the body and may be preferred for more frequent, more severe or bothersome outbreaks.

Choosing between cream and tablets is a separate decision from choosing between aciclovir and valaciclovir. Your prescriber or pharmacist can help you decide which option may be the most suitable for your needs.

Comparison at a Glance

Key Takeaways

• Aciclovir and valaciclovir can both be effective treatments for cold sores when started early. Neither is generally considered more effective than the other.
• Aciclovir is commonly taken as 200mg five times a day, or 400mg three times a day, usually for five days.
• Valaciclovir is usually taken as 2g twice in one day for cold sores, rather than over several days.
• Aciclovir is generally the lower cost option, while valaciclovir offers the convenience of a much shorter treatment course.
• Always follow the dose and treatment plan recommended by your prescriber or provided in your patient information leaflet.