{"id":629157,"date":"2024-08-01T09:30:32","date_gmt":"2024-08-01T13:30:32","guid":{"rendered":"https:\/\/www.singlecare.com\/blog\/?p=629157"},"modified":"2026-04-17T18:40:05","modified_gmt":"2026-04-17T22:40:05","slug":"how-long-does-valacyclovir-take-to-work","status":"publish","type":"post","link":"https:\/\/www.singlecare.com\/blog\/how-long-does-valacyclovir-take-to-work\/","title":{"rendered":"How long does it take valacyclovir to work?"},"content":{"rendered":"

Valacyclovir, sold under the brand name Valtrex, is an <\/span>antiviral<\/span><\/a> medication that is<\/span> approved <\/span>to treat viral infections, including herpes simplex virus (genital and cold sores) and varicella-zoster<\/span> virus, which can cause chickenpox and shingles.<\/span><\/p>\n

\u00a0<\/span>People who take <\/span>valacyclovir may wonder: How long does it take for valacyclovir to work? <\/span>Thankfully, <\/span>valacyclovir works fairly quickly once you take it. \u201cValacyclovir typically begins to take effect within two to three days, sometimes sooner, after the first dose,\u201d says <\/span>Soma Mandal, MD, an internist at Summit Health.<\/span><\/p>\n

\u00a0<\/span>Here, we\u2019ll go over everything you need to know about how long it takes valacyclovir to work, including factors that affect how long it takes, proper dosing of valacyclovir, and if there are certain situations where you should not take valacyclovir.<\/span><\/p>\n

RELATED:<\/b> Acyclovir vs. valacyclovir: Differences, similarities, and which is better for you<\/span><\/a><\/p>\n

How long does valacyclovir take to work?\u00a0<\/span><\/h2>\n

If<\/span> you are dealing with a herpes outbreak, chickenpox, or <\/span>shingles<\/span><\/a>, you want relief as soon as possible. The good news is that valacyclovir provides fairly quick relief from symptoms.<\/span><\/p>\n

\u00a0<\/span>So, how fast does valacyclovir work, exactly? \u201cWithin one to two hours of taking the first dose, valacyclovir is already working to shorten the course of your infection,\u201d says<\/span> Jacob Siegel, MD<\/span><\/a>, assistant professor in Dermatology at Yale School of Medicine. \u201cWhile you will not feel it working, you will know it helps when you start to notice lesions crusting over and healing more quickly.\u201d<\/span><\/p>\n

\u00a0<\/span>Raman Madan, MD, chief of dermatology at<\/span> Glen Cove Hospital<\/span><\/a>, concurs. While valacyclovir is absorbed quickly and starts to work within hours of taking it, he says you may not notice results for a few days, noting that the sooner you take your first dose, the more effectively it will work. \u201cIt is best used within 72 hours of symptom onset,\u201d he says.<\/span><\/p>\n

Signs that valacyclovir is working<\/span><\/h3>\n

How might you know that the medication has started to work? \u201cYou can tell it’s working if you notice less pain, itching, and fewer sores,\u201d says <\/span>Raj Dasgupta<\/span>, MD, a q<\/span>uadruple board-certified physician specializing in internal medicine, pulmonology, critical care, and sleep medicine, and reviewer at the<\/span> National Council on Aging<\/span><\/a>. \u201cThe medication has fully kicked in when your symptoms are mostly gone, which typically happens within a few days, but it might take longer for some people.\u201d<\/span><\/p>\n

\u00a0<\/span>Most people can tell valacyclovir is starting to work when they observe a reduction in the severity and duration of their symptoms, Dr. Mandel says. \u201cFor example, in the case of HSV, there should be less pain, itching, and a reduction in the number of skin lesions,\u201d she describes. \u201cWith shingles, people often notice a decrease in the intensity of pain and the size of the rash.\u201d Dr. Mandel adds that full resolution of your symptoms and full healing of any rashes or skin lesions indicate the full effectiveness of valacyclovir.<\/span><\/p>\n

What can affect how long it takes valacyclovir to work?<\/span><\/h2>\n

How fast valacyclovir works can depend on:<\/span><\/p>\n