Valacyclovir 500 mg vs 1000 mg: dosing for cold sores, genital herpes and shingles

Valacyclovir is the most reordered antiviral in our store, and the 500 mg and 1000 mg packs sit next to each other on the shelf. The question in the inbox is never “does it work”. It’s “which one do I need”, followed a week later by “I bought the wrong one, can I take two”. Fair questions. The product pages list strengths and prices; they don’t tell you that a cold sore needs four of one tablet and a recurrence needs six of the other.

So this is the dosing guide we’d hand over the counter if we had a counter. Which strength for which regimen, how many tablets a course burns through, and which pack size stops you paying for tablets that will expire before you use them. Five minutes. Then you’ll know exactly what goes in the cart.

The short answer

Valacyclovir 500 mg is the tablet for things you do often: three-day treatment of a genital herpes recurrence, and one-a-day suppression. Valacyclovir 1000 mg is the tablet for things you do in big doses: cold sores (2 g at a time), a first episode of genital herpes (1 g at a time), and shingles (1 g at a time, three times a day). If you’re only going to keep one strength in the cabinet, 500 mg is the more flexible — two of them make a gram. But four 500s per cold-sore dose gets old fast, and the 1000 mg packs are cheaper per gram.

Same drug, two tablet sizes

Both packs contain valacyclovir hydrochloride, made by Cipla or Sun Pharma, in blister strips of ten. It is the generic of Valtrex and the same molecule in every respect. Once swallowed, the gut absorbs it well and the liver converts it to acyclovir — the drug that actually stops the herpes virus copying itself. That good absorption is the whole point: it’s why one valacyclovir tablet twice a day does the work of acyclovir five times a day. We compared the three herpes antivirals in more depth in our acyclovir vs valacyclovir vs famciclovir guide; this post is only about the two valacyclovir strengths.

A 1000 mg tablet is not a different medicine. It is two 500 mg tablets fused into one, priced slightly lower per milligram. So the question is never “which is stronger” — it’s “which regimen am I on, and how many milligrams does each dose need”.

Cold sores: 2 g twice, one day

The licensed valacyclovir regimen for cold sores (herpes labialis) is 2 g twice in one day, roughly 12 hours apart. That is two 1000 mg tablets in the morning and two in the evening. Four tablets, one day, finished. With 500 mg tablets it’s the same 4 g total but eight tablets, four at a time — doable, just clumsy.

The timing line is everything. The one-day regimen was tested in people who took the first dose at the first sign — the tingle, the itch, the tightness on the lip — and it doesn’t do much once the blister is already up. The cold-sore customers who get the most out of this drug are the ones who keep a strip in the bathroom, one in the desk, one in the travel bag. The ones who order after the blister appears are two weeks and a healed lip too late, and we’d rather tell them that than take the order.

Genital herpes: first episode vs recurrence vs suppression

Three situations, three regimens, and the strength you want flips between them. This is where most wrong-pack orders happen.

First episode: 1000 mg

The first outbreak gets the biggest, longest course: 1 g twice daily for 10 days. Twenty tablets of 1000 mg — one 30-pack, with ten spare for the next situation on this list. Using 500 mg tablets instead means forty of them, two per dose; that works pharmacologically but a 30-pack of 500s won’t get you through the course. A first episode also needs a doctor: it’s the one time the diagnosis genuinely should be confirmed with a swab, and some doctors extend the course if the sores haven’t healed by day ten.

Recurrences: 500 mg

Later outbreaks are milder and shorter, and the regimen is 500 mg twice daily for 3 days. Six tablets. Here the 500 mg strength is exactly right and a 1000 mg tablet would be double the dose — don’t halve a 1000 mg film-coated tablet to get there; buy the right pack. A 30-pack of 500 mg at $131.99 is five recurrence courses. Start at the prodrome — tingling, itching, a shooting pain in the buttock or thigh — not at the blister.

Suppression: 500 mg daily, sometimes 1 g

If you get frequent outbreaks (the usual threshold is six or more a year) or want to lower the risk of transmitting to a partner, the daily option is 500 mg once a day. One tablet, morning or night, no alarms. For people with very frequent outbreaks — ten or more a year — doctors often step up to 1 g daily, which you can take as one 1000 mg tablet or two 500s.

Daily suppression is where the pack size matters most, because you’ll be buying it for months or years:

• → 500 mg daily: 30 tablets a month. The 360-pack at $600.99 is twelve months at $1.67 a day, delivery included.
• → 1 g daily as one 1000 mg tablet: the 180-pack at $344.99 is six months at $1.92 a day, delivery included.
• → 1 g daily as two 500s: the 360-pack is six months at $3.34 a day. The 1000 mg tablets are the better buy here.

Most doctors review suppression after a year — some people stop and find outbreaks have become rare on their own. So a year’s supply is a sensible maximum in one order, not a lifetime’s.

Shingles: 1 g three times a day

Shingles is a different virus — varicella-zoster, the chickenpox one — and it needs about three times the total daily dose of a herpes simplex outbreak. The regimen is 1 g three times daily for 7 days: 21 tablets of 1000 mg, which a 30-pack covers with nine spare. With 500 mg tablets that’s 42, so the 1000 mg pack is the obvious choice.

Two things we say to every shingles customer. First, the 72-hour clock: valacyclovir reduces the chance of the lingering nerve pain that can follow shingles for months, but the benefit depends on starting within 72 hours of the rash. Second, a shingles rash on the face or anywhere near the eye is a same-day doctor visit — the eye can be damaged, and that needs a specialist, not a parcel in two weeks. If you have a pack at home from an earlier course and a doctor confirms shingles by phone, that’s when it earns its place in the cabinet.

Which pack to buy: the tablet-count table

All the regimens above in one place, with our current pack prices. The “buy” column is the smallest pack that covers the course.

The full price ladders, since people ask: Valacyclovir 500 is $131.99 for 30 ($4.40 each), $174.99 for 60, $216.99 for 90, $259.99 for 120, $344.99 for 180 and $600.99 for 360 ($1.67 each). Valacyclovir 1000 is priced the same at every shared size: $131.99 for 30 ($4.40 each), $174.99 for 60, $216.99 for 90, $259.99 for 120 and $344.99 for 180 ($1.92 each). Delivery is free and tracked on every order to our supported countries; see the shipping page.

Our honest steer on a “one pack for everything” order: if you get both cold sores and genital recurrences, buy the 500 mg pack. Two tablets make the 1 g doses when needed, and one tablet is the right size for recurrences and suppression. If you only ever get cold sores, or you’ve been told it’s shingles, buy the 1000 mg.

Side effects, kidneys and who needs a doctor first

Valacyclovir is a gentle drug for most people. The common complaints, in the order we hear about them:

• Headache — the most frequent, usually mild
• Nausea — taking it with food helps, and food doesn’t reduce absorption
• Dizziness — more likely on the 2 g cold-sore doses
• Stomach pain or diarrhoea
• Tiredness
• A mild rash — stop and check with a doctor if it spreads

The organ to think about is the kidney. Acyclovir — which is what valacyclovir turns into — is cleared by the kidneys and can crystallise in them at high doses if you’re short of fluid. So: drink water through every course, especially on the shingles and cold-sore regimens where the per-dose amounts are large. Anyone with reduced kidney function needs the dose lowered by a doctor, and the high-dose regimens are the ones where that matters most. Older customers fall into this group more often than they expect.

Rare but serious: confusion, hallucinations, agitation or unusual drowsiness, most often in older people or those with kidney problems on high doses. That’s a same-day call to a doctor. And valacyclovir has a good pregnancy record — it’s generally the antiviral doctors choose when treatment is needed in pregnancy, including near delivery — but that’s a decision for the doctor managing the pregnancy, not for a checkout page.

Questions we get asked

Can I take two 500 mg tablets instead of one 1000 mg?

Yes. They’re the same drug and two 500s deliver the same 1 g dose. It’s the reverse that’s a problem — a 1000 mg film-coated tablet isn’t designed to be halved accurately for a 500 mg dose. If your regimen calls for 500 mg, buy the 500 mg pack.

How fast does valacyclovir work on a cold sore?

Started at the first tingle, the 2 g twice-in-a-day regimen typically shortens the episode by around a day and can stop some from blistering at all. Started after the blister is fully up, it does little. It never removes the virus; the next cold sore is still possible.

Do I have to take the whole course if the sores heal early?

Yes. Finish the course as prescribed — 3 days for a recurrence, 10 for a first episode, 7 for shingles. Stopping early because it looks better is how outbreaks drag on or come straight back.

Which strength is right for daily suppression?

Usually 500 mg once a day. Doctors move up to 1 g daily for people with very frequent outbreaks. The 360-pack of 500 mg ($600.99) is a year’s supply at $1.67 a day; the 180-pack of 1000 mg ($344.99) is six months of the 1 g regimen.

Does food matter?

No — valacyclovir absorbs the same with or without food. Taking it with a snack helps if it makes you queasy. What matters is water: drink plenty through the course, because the drug is cleared by the kidneys.

Can I use valacyclovir 1000 mg for a recurrence?

The label dose for a recurrence is 500 mg twice daily, so a 1000 mg tablet would be double. Some doctors do prescribe 1 g once daily for 5 days as an alternative recurrence regimen — but that’s their call to make. Don’t improvise the dose from the pack you happen to have.

What to do now

Work out which of the seven rows in the table you’re on. Cold sores, first episode or shingles: open the Valacyclovir 1000 mg page and the 30-pack covers any of them. Recurrences or daily suppression: open the Valacyclovir 500 mg page, and if suppression is the plan, the 180 or 360 pack is the one that makes sense on price and ships free. Order before you need it — delivery is 10–18 working days, and a cold sore doesn’t wait. If you’re pregnant, have kidney trouble, or this is your first outbreak, see a doctor first. And if you’re still torn between the two strengths, email us; we’ll tell you which pack we’d put in the box.

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