Acyclovir vs Valacyclovir

What you need to know about the two most common drugs to treat herpes.


A herpes outbreak can be an unpleasant experience to deal with. Sadly, there is no cure for the herpes simplex (HSV) or herpes zoster virus. But there are a few medical treatment options from which you can choose.

The most common drugs to treat herpes are antivirals such as acyclovir, valacyclovir, and famciclovir. Among them, acyclovir and valacyclovir are most frequently prescribed. Let’s find out how they work and what the differences between them are.

Order safe and effective treatment for genital herpes

Product Img
Famciclovir from $18.00
Product Img
Valacyclovir from $16.00
View all treatments

What are Acyclovir and Valacyclovir?

When you suffer a herpes outbreak (cold sores, genital herpes or shingles) your doctor may prescribe oral medications such as acyclovir or valacyclovir.

The drugs work in a similar way by preventing HSV from replicating and spreading, to control a herpes outbreak and help heal symptoms faster. They are effective against HSV-1, HSV-2 and herpes zoster.  

Both acyclovir and valacyclovir can be used for the immediate treatment of HSV outbreaks or long-term suppression therapy. Suppression therapy benefits patients who have frequent recurrences of genital or oral herpes.

In addition, studies have shown that both drugs lower the risk of oral or sexual transmission of the herpes virus to others.


What is Acyclovir?

Acyclovir (aciclovir) has been around since the 1970s. It is one of the oldest herpes treatments and is also prescribed for chickenpox.

The dosage and duration of acyclovir treatment, often depends on the severity of symptoms and whether your immune system is normal or compromised.

Most adults are ordered to take 200 mg of the drug 5 times a day for 5 days. Patients usually experience some relief of symptoms after 2 days, but blisters and sores can take up to 2 weeks to heal.

The medication has a half-life of 2.5 to 3.3 hours which means that the drug will stay in your system for around 24 hours.

Acyclovir is also available as a cream to treat cold sores. 

Although many doctors still prescribe acyclovir, valacyclovir is preferable for long-term management of HSV.


What is Valacyclovir?

Valacyclovir (valaciclovir) has been around since the 1990s. It is a pro-drug, which means it converts into its active form once inside the body. The active ingredient of valacyclovir is acyclovir.

The benefit of valacyclovir is that it has a higher bioavailability, so more of the active ingredient reaches the target organs.

Because of this, patients usually need the medication for a shorter duration and with less frequeny.  For herpes zoster, patients can take 1000 mg daily for seven days.  For oral herpes, patients can take 2000mg, 12 hours apart, for two doses only.

It has the same half-life of 2.5 to 3.3 hours once converted into acyclovir.

Studies have shown that both antiviral medications are useful in suppressing genital viral shedding and reduce the frequency of genital herpes outbreaks.


Acyclovir versus Valacyclovir

The action, efficacy, and safety of acyclovir and valacyclovir are highly similar. Both medications are useful in treating HSV infections and minimizing the recurrence of outbreaks.

Acyclovir has been extensively tested in clinical trials and is deemed safe for long-term use and use during pregnancy. Because the active ingredient in valacyclovir is acyclovir, the same applies.

To help you decide which one to choose, here’s an overview of the two antiviral drugs:

Emergency Contraception

Both acyclovir and valacyclovir are useful for the treatment of HSV. Speak to your doctor about the best treatment option if you think you may have herpes, shingles or chickenpox.



  1. Razonable R. R. (2011). Antiviral drugs for viruses other than human immunodeficiency virus. Mayo Clinic proceedings, 86(10), 1009–1026. doi:10.4065/mcp.2011.0309
  2. Gupta, R., Wald, A., Krantz, E., Selke, S., Warren, T., Vargas?Cortes, M., … Corey, L. (2004). Valacyclovir and Acyclovir for Suppression of Shedding of Herpes Simplex Virus in the Genital Tract. The Journal of Infectious Diseases, 190(8), 1374–1381.
  3. Schuster, A. K., Harder, B. C., Schlichtenbrede, F. C., Jarczok, M. N., & Tesarz, J. (2016). Valacyclovir versus acyclovir for the treatment of herpes zoster ophthalmicus in immunocompetent patients. Cochrane Database of Systematic Reviews.
  4. Kang, S. H., Chua-Gocheco, A., Bozzo, P., & Einarson, A. (2011). Safety of antiviral medication for the treatment of herpes during pregnancy. Canadian family physician Medecin de famille canadien, 57(4), 427–428.

Buy antivirals for genital herpes treatment from Medzino, your trusted online pharmacy


Complete a quick consultation, choose a FDA
approved treatment and get it shipped for free.

Free shipping on all orders

Your trusted online doctor

Free shipping on all orders
Order now for delivery on Wednesday