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how fast does valtrex work

Valtrex (valacyclovir) starts working within hours of your first dose, but most people notice symptom improvement in about 2–5 days , depending on what you’re treating and how early you start.

How fast it starts working

  • Within 1–3 hours : Valtrex is absorbed and converted to acyclovir, its active form, so the drug is already “working” against the virus soon after you swallow it.
  • Within 2–3 days : Many people see lesions begin to crust over, pain and itching lessen, and healing speed up, especially if treatment is started early.

By condition (how fast it “feels” like it’s working)

Cold sores (herpes labialis)

  • Often shortens the outbreak by about 1 day if you start at the first tingle or blister.
  • Many people notice less pain and faster crusting within 2–3 days.

Genital herpes

  • Works best if started within 48 hours of symptoms; starting later may still help but effect can be less dramatic.
  • Improvement in pain, new lesion formation, and healing usually becomes noticeable in 2–5 days.

Shingles (herpes zoster)

  • When taken early in the rash, it can shorten the duration of pain and rash by several days.
  • Many patients report less new blistering and easing of pain within 2–3 days.

When timing really matters

  • Best window : For cold sores and genital herpes, starting Valtrex within 72 hours of symptom onset gives the biggest benefit.
  • Earlier = better : The sooner you take it after tingling, burning, or the first bump, the more likely you are to see faster relief and shorter outbreaks.

Quick‑reference table

Condition| When it starts working (biologically)| When people usually notice improvement
---|---|---
Cold sores| Within 1–3 hours 13| 2–3 days 35
Genital herpes| Within 1–3 hours 15| 2–5 days 58
Shingles| Within 1–3 hours 15| 2–5 days 58

If you tell me which condition you’re asking about (cold sores, genital herpes, shingles, or something else), I can tailor the timing and dosing expectations more precisely. Information gathered from public forums or data available on the internet and portrayed here.