What Is Valtrex? Uses, Dosage, and What You Need to Know in 2026

Valtrex is a brand-name prescription antiviral medication. Its generic name is valacyclovir, and it is manufactured by GlaxoSmithKline. It was FDA-approved in December 1995 and has since become one of the most prescribed medications in the United States — filling more than 7 million prescriptions per year as of 2023. If you've been prescribed Valtrex, here's everything you need to know.

What Is Valtrex Used For?

Valtrex is FDA-approved to treat infections caused by herpes viruses. Specifically, it is approved for:

Cold sores (herpes labialis) in adults and children 12 years and older

Genital herpes (herpes simplex virus type 2) — both initial episodes and recurrent outbreaks

Suppression of genital herpes — reducing outbreak frequency in people with recurrent herpes, including HIV-positive patients

Reduction of genital herpes transmission to uninfected partners

Shingles (herpes zoster) in immunocompetent adults

Chickenpox (varicella) in children 2 years and older

Importantly, Valtrex does NOT cure herpes infections. The herpes virus stays dormant in the body even between outbreaks. What Valtrex does is reduce the severity, duration, and number of outbreaks, and lower — though not eliminate — the risk of transmission.

What Is Valtrex's Generic Name?

Valtrex's generic name is valacyclovir (sometimes spelled valaciclovir in non-US countries). Generic valacyclovir is available from multiple manufacturers and is therapeutically identical to brand-name Valtrex. It has been available as a generic since 2007 and is significantly less expensive than the brand version.

What Doses Does Valtrex Come In?

Valacyclovir oral tablets are available in two strengths:

500 mg — the most commonly prescribed strength, used for suppressive therapy and some episodic treatments

1,000 mg (1 g) — used for initial genital herpes treatment, shingles, cold sores, and some recurrent outbreak regimens

Valacyclovir can also be compounded into an oral suspension (liquid) for children who cannot swallow tablets.

What Are the Dosing Regimens for Valtrex?

Dosing varies significantly by condition. Your prescriber will choose the right regimen for you:

Cold sores: 2,000 mg (2 g) twice in one day, 12 hours apart — start at the first sign of tingling

Genital herpes (first episode): 1 g twice daily for 10 days — most effective when started within 48 hours of onset

Genital herpes (recurrent episodes): 500 mg twice daily for 3 days — most effective within 24 hours of first symptom

Genital herpes (suppressive therapy): 500 mg to 1 g once daily — ongoing, to prevent outbreaks

Shingles: 1 g three times daily for 7 days — start within 72 hours of rash onset

Chickenpox (children): 20 mg/kg (up to 1 g) three times daily for 5 days — starting within 24 hours of rash onset

How to Take Valtrex

Can be taken with or without food — taking with food reduces nausea

Drink plenty of water (6–8 glasses daily) while taking valacyclovir

Take doses at evenly spaced intervals — if twice daily, space approximately 12 hours apart

Start as soon as symptoms begin — the earlier you start, the more effective the treatment

Complete the full course even if symptoms improve before you're done

Is Valtrex a Controlled Substance?

No. Valacyclovir (Valtrex) is not a controlled substance. It does not require a DEA-registered prescriber, has no prescription refill limits based on scheduling, and can be prescribed via telehealth in all 50 states.

Bottom Line

Valtrex (valacyclovir) is a safe, widely available antiviral that has been in use since 1995. It treats cold sores, genital herpes, shingles, and chickenpox — and it's one of the most prescribed medications in the US for good reason: it works. For a deeper dive into how it works at the cellular level, see our article How Does Valtrex Work?.