Last updated: October 2026
Cold sores are small, painful blisters on or around the lips, caused by the herpes simplex virus, usually type 1 (HSV-1). They start with tingling, then blister, burst and crust over, and the NHS says they usually clear up on their own within 10 days. Antiviral creams from a pharmacy work best started at the first tingle.
Below: the stages, triggers including stress, what speeds healing, how to avoid passing it on and when to get help.
What are cold sores?
A cold sore is a cluster of small blisters, usually on the lip, sometimes around the nose. NICE guidance for GPs says herpes simplex virus type 1 causes more than 90% of cases.
The virus is very common: NICE quotes estimates that 67% of people aged 0 to 49 carry HSV-1, usually caught in childhood from a kiss. It then stays in your nerves for life. About 40% of carriers get repeat cold sores, typically 2 or 3 times a year, and they tend to ease after 35.
Are cold sores herpes? Yes, but a cold sore says nothing about your sex life, as most people catch HSV-1 as children. It can be passed to the genitals through oral sex, though.
Cold sore stages: what you notice and what to do
A first-ever cold sore is often the worst and can take 10 to 14 days, NICE says. Repeat ones are usually shorter and milder.
| Stage | What you notice | What to do |
|---|---|---|
| 1. Tingling (6 to 48 hours before a blister) | Tingling, itching or burning, with nothing to see yet | Start an antiviral cream now: this is when it works best. Stop kissing from here. |
| 2. Blister (over the next 48 hours) | One or more small, painful, fluid-filled blisters, often in a cluster | Keep dabbing on cream (don’t rub). Painkillers if needed. Don’t squeeze or pop it. |
| 3. Weeping | Blisters burst and leave a shallow, sore, wet patch | The most contagious point. Wash your hands after touching it. A cold sore patch can cover it. |
| 4. Crust | A yellow or brown scab forms and may crack or itch | Leave the scab alone. Your own lip balm may feel more comfortable. Still contagious. |
| 5. Healing (usually within 10 days) | The scab falls off and the skin heals, usually without a scar | See a GP if it hasn’t started to heal within 10 days. |
The NHS says cold sores are contagious from the first tingling feeling until they have completely healed.
What triggers a cold sore?
The virus sits quietly in a nerve and wakes up now and then. The NHS and NICE list these triggers:
- Stress, physical or emotional. See stress symptoms.
- Tiredness and running on too little sleep. See sleep debt.
- Colds, flu and other illness, especially with a fever. See cold vs flu.
- Strong sunlight and sunbeds.
- Periods. See PMS symptoms.
- Injury to the lip, including dental work.
- Very hot or cold weather, and a weakened immune system.
Can stress cause cold sores?
Stress can’t give you the virus, but it seems to wake it up. A 2009 meta-analysis of 11 prospective studies found a small but consistent link between psychological stress and herpes flare-ups, stronger for cold sores than genital herpes. Feeling distressed mattered more than stressful events themselves.
How to get rid of a cold sore fast
There’s no cure, but you can shorten a cold sore a little, ease the pain and protect the skin.
Antiviral creams: start at the tingle
Pharmacies sell antiviral creams containing aciclovir or penciclovir. The NHS says to start at the first tingle, as they may not work once blisters appear. Follow the leaflet.
Expect a modest effect. In two trials of aciclovir cream in 1,385 adults, cold sores lasted about half a day less than with a dummy cream (4.3 versus 4.8 days, and 4.6 versus 5.2 days). Penciclovir cream healed sores 0.7 days faster in 1,573 people (4.8 versus 5.5 days). NICE calls the benefit marginal, so GPs don’t routinely prescribe them.
Cold sore patches
Clear hydrocolloid patches cover the sore to protect the skin while it heals, and can make it less noticeable. In one trial of 351 people, a patch and aciclovir cream gave similar healing times (median 7.6 versus 7.0 days).
Other things that help
- Paracetamol or ibuprofen for pain and swelling, if they’re suitable for you.
- Plenty of fluids, and skip acidic or salty foods if they sting.
- Antiviral tablets from a GP may be an option if your cold sores are very large, very painful or keep coming back.
The NHS says there isn’t much evidence for light or laser devices.
Should you pop a cold sore?
No. The fluid is full of virus, so popping or picking can spread it to your fingers, face and other people. The NHS says not to touch it except to dab on cream, and to wash your hands before and after.
Does lysine help?
The evidence is weak. A Cochrane review found no evidence that lysine prevents cold sores, and a 2017 review found doses under 1g a day appear ineffective, with better trials needed. Ask your GP first if you have heart or gallbladder disease. For the small trials of lemon balm cream, see our lemon balm guide.
How to avoid spreading a cold sore
From the first tingle until it has completely healed:
- Don’t kiss anyone, and avoid oral sex, which can pass the virus to a partner’s genitals.
- Never kiss a baby. Cold sores can cause neonatal herpes, rare but very dangerous for newborns.
- Don’t share towels, cups, cutlery, lip balm, lipstick or make-up, or your cold sore cream.
- Wash your hands with soap and water whenever you touch the sore.
- Keep it away from your eyes, and take extra care with contact lenses, NICE advises.
How to stop cold sores coming back
You can’t clear the virus, but you can cut down the triggers.
- Wear an SPF lip balm. The NHS advises SPF 15 or above outdoors, and avoiding sunbeds. Trials are mixed: sunscreen prevented cold sores triggered by artificial UV, but one trial in natural sunlight found no clear benefit.
- Look after sleep and stress. Not proven to prevent cold sores, but worth it for its own sake. See how to calm down, lowering cortisol naturally and sleep hygiene.
- Protect dry, cracked lips in winter. See our guide to dry skin.
- Keep cream at home if yours arrive with every cold or sore throat, so you can start at the first tingle.
If you get them often (NICE suggests specialist advice at 6 or more a year), talk to a GP. A Cochrane review found daily antiviral tablets taken for months reduced repeat cold sores slightly; antiviral cream used to prevent them didn’t work.
Staying well this winter
No food or supplement prevents cold sores. For the basics, see supporting your immune system, vitamin C, zinc and winter wellness. The NHS advises everyone to consider 10 micrograms of vitamin D a day from about October to early March (no more than 100 micrograms). Vitamin D contributes to the normal function of the immune system. See vitamin D in winter.
For winter vitamin D in a daily drop, our Mint CBD Oil with Vitamin D3 contains 5 micrograms of vegan vitamin D3 per half pipette, alongside broad spectrum CBD with 0% THC. CBD isn’t a treatment for cold sores or any infection. If you take another vitamin D product, add both together towards your daily total.
The FSA’s 10mg a day figure is precautionary advice rather than a legal limit, set while longer-term safety research continues. At Evopure we think it is a very cautious figure, and many adults use more. If you go above it, increase slowly, and check with your GP or pharmacist first if you take any medication.
Our products are for adults (18+) only, and we don’t recommend our products during pregnancy or breastfeeding.
Cold sore or something else?
| Cold sore | Mouth ulcer | Impetigo | |
|---|---|---|---|
| Where | On or around the lips, sometimes the nose | Inside the mouth: cheeks, inner lips, tongue | Often around the nose and mouth (a bacterial infection) |
| Looks like | Tingle first, then a cluster of small fluid-filled blisters that crust | Round, white, often painful sores | Red sores that burst and leave golden-brown crusts |
| Contagious? | Yes | No | Yes |
| What helps | Pharmacy antiviral cream or patch | Usually heals in 1 to 2 weeks | See a pharmacist or GP for treatment |
If you’re not sure what it is, a pharmacist can take a look.
Cold sores in pregnancy, babies and children
Pregnancy
Tell your midwife or GP about a cold sore in pregnancy, and ask a pharmacist before using any cream. NICE says the main concern is a first-ever infection in the third trimester, especially the last 6 weeks, before your body can pass protective antibodies to your baby. We don’t recommend our products during pregnancy or breastfeeding.
Newborns and babies
The NHS says the first 6 weeks carry the most risk. Nobody with a current or recent cold sore should kiss the baby, and everyone should wash their hands before handling them. Breastfeeding with a cold sore? Wash your hands first and cover the sore.
Children
A child’s first infection can cause swollen, painful gums and mouth sores (gingivostomatitis): see a GP. Liquid paracetamol is available for children; never give aspirin to under-16s. Well children with a cold sore can still go to nursery or school, NICE says.
When to see a GP or get urgent help
See a GP if
- the cold sore hasn’t started to heal within 10 days
- it’s very large or painful, or you’re not sure what it is
- you or your child also have swollen, painful gums and mouth sores
- you have a weakened immune system, for example from chemotherapy or diabetes
- you get cold sores very often
Get an urgent GP appointment or call 111 if
- your eye becomes painful or red, or your eyesight changes: the virus can infect the eye
- you have eczema and it becomes blistered, painful or suddenly worse (a possible serious herpes skin infection)
- you’re pregnant and think this is your first ever cold sore or herpes infection
- a baby has sores on the skin, eyes or mouth, isn’t feeding well, is irritable or has a temperature of 38C or more
Call 999 if
- a baby is floppy, hard to wake, struggling to breathe or has a fit
- you have a red eye and it hurts to look at light, the eye is very dark red, or one pupil is bigger than the other
Sores inside the mouth are usually mouth ulcers, which aren’t contagious: see mouth ulcers.
FAQs
How long do cold sores last?
Usually up to 10 days, the NHS says, and a first-ever cold sore can take 10 to 14. See a GP if one hasn’t started to heal after 10 days.
Are cold sores contagious?
Yes, from the first tingle until completely healed, and most of all when the blisters burst. Avoid kissing, oral sex and sharing towels, cups or lip products.
Can stress cause cold sores?
Stress can trigger a cold sore if you already carry the virus. A 2009 meta-analysis found a small but consistent link between psychological stress and herpes flare-ups.
What is the fastest way to get rid of a cold sore?
Start a pharmacy antiviral cream such as aciclovir at the first tingle; in trials it shortened cold sores by about half a day. A GP can prescribe tablets for severe or frequent ones.
Should I pop a cold sore?
No. Popping or picking can spread the virus to your fingers, face and other people. Don’t touch it except to dab on cream, and leave it to crust on its own.
Are cold sores the same as herpes?
Yes. Cold sores are caused by the herpes simplex virus, usually type 1, which most people catch in childhood. It can spread to the genitals through oral sex.
Sources
- NHS. Cold sores.
- NICE Clinical Knowledge Summaries. Herpes simplex: oral (revised May 2024).
- NHS. Neonatal herpes.
- NHS. Herpes simplex eye infections.
- NHS. Vitamin D.
- Spruance SL et al (2002). Acyclovir cream for treatment of herpes simplex labialis: two randomized trials. Antimicrob Agents Chemother. PMID 12069980.
- Spruance SL et al (1997). Penciclovir cream for the treatment of herpes simplex labialis. JAMA. PMID 9134943.
- Chi CC et al (2015). Interventions for prevention of herpes simplex labialis (cold sores on the lips). Cochrane Database Syst Rev. PMID 26252373.
- Chida Y, Mao X (2009). Does psychosocial stress predict symptomatic herpes simplex virus recurrence? A meta-analysis. Brain Behav Immun. PMID 19409481.
- Karlsmark T et al (2008). Randomised study comparing a hydrocolloid cold sore patch with aciclovir 5% cream. J Eur Acad Dermatol Venereol. PMID 18462303.
- Mailoo VJ, Rampes S (2017). Lysine for herpes simplex prophylaxis: a review of the evidence. Integr Med. PMID 30881246.
This guide is general information, not medical advice. Evopure makes the Mint CBD Oil with Vitamin D3 (Evolabs).
