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How to Stop a Herpes Outbreak with Valtrex (Valacyclovir)

Reviewed by Kelly Brown, MD

Written by Vanessa Gibbs

Published 07/05/2018

Updated 02/23/2024

Valacyclovir (the generic for Valtrex®) can reduce your symptoms and shorten the amount of time an outbreak lasts. But you need to take it fast — we’re talking within 24 hours of symptoms starting in some cases.

But how much should you take? The valacyclovir dose for cold sores is different from the dose for genital herpes, and the dose also depends on whether this is your first rodeo or if you’ve experienced outbreaks before.

Ahead, learn how to stop a herpes outbreak in its tracks and what Valtrex dose to take.

How to Tell a Herpes Outbreak Is Coming

First, a quick biology lesson. Herpes is caused by the herpes simplex virus (HSV). While there are a few different types, we’re talking about two types of HSV here:

  • Herpes simplex virus type 1 (HSV-1), which mostly causes oral herpes, or cold sores

  • Herpes simplex virus type 2 (HSV-2), which mostly causes genital herpes

However, if you receive oral sex from someone with HSV-1, you can get genital herpes caused by HSV-1. And vice versa. You can learn more in our guide on HSV-1 and HSV-2.

Some — many, in fact — lucky folks don’t get any symptoms at all, while other people get mild symptoms that could be mistaken for a pimple or ingrown hair.

But most people who get symptoms experience herpes lesions, or small blisters, which develop around the mouth, genitals or rectum.

But before lesions pop up, you may experience some tell-tale signs an outbreak is coming. These are known as prodromal symptoms.

Early signs of oral herpes, which you may feel in the area where a cold sore is about to pop up, include:

  • Tingling

  • Itching

  • Burning

For genital herpes, early signs include:

  • Localized genital pain

  • Tingling in the legs, hips or butt

  • Shooting pains in the legs, hips or butt

You may notice these symptoms a few hours or even days before lesions appear.

During your first herpes outbreak, you might also get flu-like symptoms such as:

  • Fever

  • Body aches

  • Headache

  • Swollen lymph nodes near the infection

  • Sore throat (for cold sores)

You may also get herpes symptoms that aren’t sores at all, such as:

  • Genital itching

  • Irritation

  • Excoriations (sore red skin that starts to peel)

  • Painful urination

The silver lining is symptoms of your next outbreaks are usually shorter and less severe than your first. Phew.

Antiviral medications like valacyclovir, acyclovir and famciclovir can be used to treat herpes outbreaks. Want the nitty-gritty details? Check out our guide on how valacyclovir works.

herpes treatment

your outbreak is no match against an Rx option.

How Much Valacyclovir Should I Take During an Outbreak?

Valacyclovir is a medication approved by the Food and Drug Administration (FDA) to treat cold sores, genital herpes, herpes zoster (shingles) and chicken pox.

Unfortunately, valacyclovir can’t cure the herpes infection, but it can reduce the symptoms and how long lesions hang around.

How much Valtrex you should take during an outbreak and how long you need to take it for will depend on factors such as what virus you’re dealing with and if you've had it before.

FYI, you can’t get valacyclovir over the counter. You’ll need to speak with a healthcare provider to get a prescription. They can also give you medical advice on the best valacyclovir dosing for you.

Valacyclovir Dosing for Genital Herpes

A small preface here: your recommended dosage of valacyclovir is going to be whatever your healthcare provider prescribes you. Full stop. All of the information below is based on recommended guidelines, but your healthcare provider will be your best source of information for dosing.

Now that that’s out of the way…

If this is your first outbreak of genital herpes, you should take a 1,000 milligram (mg) dose of valacyclovir twice a day for 10 days.

Treatment is most effective if you take it within 48 hours of your symptoms starting.

There’s some good science backing valacyclovir for genital herpes.

For example, studies show that valacyclovir — when delivered within 72 hours of symptoms starting — can speed up healing in people with genital herpes for the first time.

A 1,000 mg dose twice a day for 10 days can lead to:

  • Lesions healing in about nine days

  • Pain stopping in about five days

  • Viral shedding (when your body produces infectious particles) stopping in about three days

If this is a recurrent genital herpes outbreak, you should take a 500 mg dose of valacyclovir twice a day for three days.

Again, you should start treatment as soon as you notice any symptoms — it’s not clear whether valacyclovir will work for recurrent herpes outbreaks if you take it more than 24 hours after your symptoms start.

Clinical trials also show that valacyclovir can help those who have had genital herpes before. 

A 500mg dose of valacyclovir twice daily for five days can lead to:

  • Lesions healing in about four days

  • Pain stopping in about three days

  • Viral shedding stopping in about two days

You can learn more in our guide to how fast valacyclovir works.

You can also take herpes meds daily to reduce how often herpes outbreaks occur and reduce the chances of passing the virus on to your sexual partner. This is known as suppressive therapy. It’s often recommended for people who get very painful or frequent outbreaks.

For suppressive therapy, people with normal immune function should take a 1,000 mg dose of valacyclovir once a day. If you get nine or fewer outbreaks a year, you might be prescribed a once-a-day 500 mg dose.

People who have HIV as well may be prescribed 500 mg of valacyclovir twice a day.

Valacyclovir Dosing for Cold Sores

The valacyclovir dose for cold sores is different from the valacyclovir dose for genital herpes.

For oral herpes, you should take a 2,000 mg dose of valacyclovir twice a day for one day, 12 hours apart.

Just like with the genital variety, you need to act fast. You should take valacyclovir for cold sores as soon as you notice the early signs. Remember, that’s tingling, itching or burning. Valacyclovir may not work as well if you take it once a blister develops.

Clinical studies on almost 1,900 patients with recurrent cold sores have found that valacyclovir can speed up the healing process.

When patients took valacyclovir quickly — most of them within two hours of noticing symptoms — their cold sores lasted on average one day less than the cold sores of people who didn’t take any treatment.

Patients receiving treatment in this study took either 2,000 mg of valacyclovir twice a day for one day or 2,000 mg of valacyclovir twice a day for one day then 1,000 mg twice a day the next day.

The two-day treatment didn’t have any benefits beyond the one-day treatment.

Valacyclovir didn’t help those who took it when the cold sore itself had already popped up.

You can learn more in our guide on valacyclovir dosage.

Other Tips for Managing a Herpes Outbreak

When you’re hit with a genital or oral herpes flare-up, there are a few things you can do beyond antiviral meds to get you through it.

  • Take over-the-counter pain medication. Oral pain meds like acetaminophen, naproxen or ibuprofen and topical meds like benzocaine and lidocaine can help reduce the pain of herpes sores.

  • Take a warm bath. Sitting in warm water for 20 minutes can ease discomfort from genital herpes. Just be sure to avoid any soaps or fizzing bath bombs. In general, keep the area clean.

  • Apply a cold compress down there. Don’t apply ice directly to your genitals. Protect your skin by wrapping an ice pack in a washcloth first.

  • Wear loose-fitting clothing. Yes, that means no skinny jeans or joggers, fellas. Let the area breathe.

  • Drink cold drinks or suck on a popsicle. This can help cool off painful cold sore symptoms.

  • Be careful of natural remedies or wacky products. They’re not always effective. For example, you can buy devices that deliver heat to areas where you feel early cold sore symptoms. This is said to stop blisters from forming, but more research needs to be done to know if these devices are effective.

  • Consider L-lysine supplements. Research suggests that a daily dose of more than 3,000 mg of L-lysine may reduce recurrence rates and improve self-reported symptoms of herpes. But more research is needed to know for sure.

  • Avoid kissing or sharing bottles or cups. You can pass on the cold sore virus through saliva or touching the sore.

Steer clear of vaginal, anal or oral sex. If you have genital herpes, you can pass on the virus by having sex. Avoid any sexual contact during an outbreak and use a condom when you don’t have symptoms as you can still pass the virus on even when you don’t have lesions. You can learn more in our guide on having sex with herpes.

herpes treatment

your outbreak is no match against an Rx option.

How to Stop a Herpes Outbreak: Key Takeaways

You might not be able to completely stop a herpes outbreak in its tracks. But you can take medication to reduce the symptoms and speed up the healing process.

Here’s what you need to know:

  • Keep an eye out for early symptoms. That includes tingling, itching or burning around your lips or tingling or pain in your genitals, legs, hips or butt.

  • Take valacyclovir when you first notice symptoms. Timing is everything when it comes to stopping a herpes outbreak. You want to take valacyclovir within 48 hours of symptoms starting for your first genital herpes outbreak and within 24 hours for recurrent outbreaks. ASAP is the name of the game for cold sores, too.

  • Your valacyclovir dosage will depend on what you’re taking it for. For cold sores, it might be 2,000 mg twice a day for one day. For genital herpes, it might be 1,000 mg twice a day for 10 days for initial outbreaks and 500 mg twice a day for three days for those who have had outbreaks before.

Herpes meds can be a godsend for those who feel an outbreak coming on, and valacyclovir isn’t your only option when it comes to herpes treatments. Dive deeper with our guide on valacyclovir vs acyclovir.

And if you do notice symptoms, you can speak to a licensed healthcare provider as part of our sexual health services to get herpes drugs online.

7 Sources

  1. Herpes simplex virus. (2023, April 5). https://www.who.int/news-room/fact-sheets/detail/herpes-simplex-virus
  2. Genital Herpes - CDC Detailed Fact Sheet. (n.d.). https://www.cdc.gov/std/herpes/stdfact-herpes-detailed.htm
  3. Genital Herpes - CDC Basic Fact Sheet. (n.d.). https://www.cdc.gov/std/herpes/stdfact-herpes.htm
  4. Mathew Jr., J. Sapra, A. (2023, August 7). Herpes Simplex Type 2 - StatPearls. NCBI. https://www.ncbi.nlm.nih.gov/books/NBK554427/
  5. Valtrex (Valacyclovir Hydrochloride) Caplets. (n.d.). https://www.accessdata.fda.gov/drugsatfda_docs/label/2008/020487s014lbl.pdf
  6. Opstelten, W., Neven, A. K., & Eekhof, J. (2008). Treatment and prevention of herpes labialis. Canadian family physician Medecin de famille canadien, 54(12), 1683–1687. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2602638/
  7. Mailoo, V. J., & Rampes, S. (2017). Lysine for Herpes Simplex Prophylaxis: A Review of the Evidence. Integrative medicine (Encinitas, Calif.), 16(3), 42–46. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6419779/
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