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Valacyclovir vs. Acyclovir vs. Famciclovir: Who Wins?

Mary Lucas, RN

Medically reviewed by Mary Lucas, RN

Written by Our Editorial Team

Last updated 7/05/2020

There are several drugs used to treat herpes, all of which are antiviral medications. The most popular, effective and widely used herpes medications currently available are valacyclovir (or Valtrex), acyclovir (or Zovirax) and famciclovir (or Famvir). All of these drugs work through a similar mechanism, and all have their place in treating cases of HSV-1 and HSV-2. But when it comes down to it, in a battle between Valacyclovir vs. Acyclovir vs. Famciclovir, which herpes medication is the best?

In this guide, we’ll compare these three herpes medications and explain which one is the best choice for treating and managing the virus.

How Do Herpes Drugs Work?

Herpes medications like valacyclovir, acyclovir and famciclovir belong to a class of medications called antiviral drugs.

Antiviral drugs are designed to inhibit the growth and development of viruses in the body. Unlike antibiotics, which eliminate the bacteria that cause infections, antiviral drugs simply control viral proliferation rather than completely eliminating the target virus from the body.

None of the antiviral drugs on the market today can cure herpes. However, consistent use of an antiviral drug like valacyclovir can make living with herpes much easier by speeding up healing after an outbreak and reducing your risk of transmitting the virus to other people.

Herpes drugs are taken for several reasons. People with active HSV-1 or HSV-2 infections can take them during outbreaks to control and treat their symptoms. Antiviral drugs are also used as part of suppressive therapy for herpes to reduce the severity and frequency of outbreaks.

Even people with asymptomatic herpes can benefit from using antiviral drugs by lowering their risk of spreading the virus to other people through sexual or oral contact.


Valacyclovir is one of the most widely used drugs for treating herpes. It’s been approved for use as a herpes treatment since 1995 and has a consistent safety record. Most people know of this drug as Valtrex, a brand name used to market the medication by GlaxoSmithKline.

Valacyclovir is a prodrug, meaning it converts into another drug inside the body. After you take a tablet of valacyclovir, it’s converted into the active substance acyclovir. Acyclovir then blocks the herpes virus from reproducing, helping to control the symptoms of a herpes outbreak.

Like other herpes medications, valacyclovir is highly effective. Studies show that it reduces the amount of time required for healing during a herpes outbreak, as well as reducing your risk of transmitting the herpes virus to other people.

Valacyclovir starts working almost as soon as you start taking it. It’s effective against all forms of the herpes virus, with different doses used to treat outbreaks of oral herpes, genital herpes and shingles.

The top reason people use valacyclovir instead of acyclovir for treating herpes is its higher level of oral bioavailability. Acyclovir is almost completely broken down by the liver when taken orally, whereas valacyclovir has an oral bioavailability level of approximately 55%.

This means that more of the drug makes it into your body, helping to control a herpes outbreak and reduce your risk of transmitting the virus.

Cheap, effective and readily available, valacyclovir is usually the first medication your doctor will recommend for a herpes outbreak. Our Valacyclovir 101 guide includes more information on this drug, including common dosages, potential side effects, interactions and brand names.

herpes treatment

your outbreak is no match against an Rx option.


Acyclovir, or ACV, is an older antiviral medication that’s still commonly used to treat herpes. It’s effective against HSV-1, HSV-2 and shingles. Acyclovir is also used to treat chickenpox and as a preventative treatment against cytomegalovirus.

Acyclovir was discovered in the late 1970s and was widely used as a treatment for herpes for decades. Although it’s still widely available and remains in use today, alternative antiviral drugs like valacyclovir tend to be prescribed more often for long-term herpes management.

When taken orally, valacyclovir converts into acyclovir after it passes through the liver. As such, the effects of acyclovir are the same as valacyclovir—faster recovery during an oral or genital herpes outbreak and a reduced risk of transmitting the virus to other people.

When it comes down to valacyclovir vs acyclovir for cold sores, the main reason people choose valacyclovir over acyclovir is its improved bioavailability, which allows a lower dose of the drug to be used in treatment. Studies show that a small 500 mg dose of valacyclovir is as effective as a larger 800 mg dose of acyclovir in treating HSV.


Famciclovir is another antiviral drug that’s used for certain herpes infections. Unlike valacyclovir and acyclovir, which are usually prescribed for HSV-1 and HSV-2, famciclovir is typically used to treat shingles, or herpes zoster.

Famciclovir was introduced in the 1990s by Novartis and is sold under as Famvir in the United States. Since 2007, it has been available as a generic medication at a relatively affordable cost.

Most prescriptions of famciclovir are for shingles, or herpes zoster. The drug is also effective at controlling HSV-1 and HSV-2 symptoms in patients with compromised immune systems and is occasionally used as an alternative to valacyclovir and acyclovir for this purpose.

herpes treatment

your outbreak is no match against an Rx option.

Which Herpes Medication is Best?

The truth is, when it comes to acyclovir vs. valacyclovir vs. famciclovir, there is no winner. Valacyclovir, acyclovir and famciclovir are all safe, proven drugs that can be used effectively as treatments for HSV-1, HSV-2, shingles and other forms of the herpes virus. What your doctor will choose to prescribe you is really all dependent on what kind of outbreak you're experiencing, the severity of your symptoms and contributing factors such as immune system health, age, etc.

Vacyclovir is technically the most popular of these drugs, but only because it can be used to treat a wide array of the most common herpes outbreaks. 

If you think you might have herpes, the best approach is to speak to your doctor about treatment options. Your doctor will be able to provide advice on the most effective drug for treating herpes based on your symptoms, immune system, lifestyle and overall health. And if your doctor can't give you a physical diagnosis on the spot, you can always ask about herpes testing.

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.