Cold sores are common, but the confusion around them doesn’t have to be.

A cold sore is a small but painful blister caused by the herpes simplex virus type 1 (HSV-1). While most people carry the virus, its symptoms vary widely from person to person.¹  In this article, we’ll break down the basics of cold sore care in a simple FAQ format, covering everything from how they spread to the best ways to use creams and immune boosters to curb cold sore breakouts as soon as possible.

Cold sores are caused by HSV-1, a super common virus that’s really easy to pass around. It spreads through simple, everyday contact, such as kissing, sharing a fork, or even accidentally touching a sore and then touching someone else.¹ Once you’ve been exposed, the virus basically moves into your nerve cells for a permanent stay. It goes into "hibernation" mode, which is why 70–80% of people actually carry the virus without even realizing it.² Think of it like a sleeping volcano: most of the time it’s totally quiet, and you’d never know it's there, but certain triggers can "wake it up" and cause a flare-up.

Symptoms may include:

• Tingling or burning before a blister appears
• Small fluid-filled blisters around the lips
• Localised pain and swelling
• Mild fever, headache, or muscle aches during the first infection¹

Most cold sores heal within two to six weeks.¹ While that might feel like a long time when you're dealing with one, catching it early with the right treatments can really help speed their recovery and healing.

Yes. Cold sores are most contagious when blisters are present, but HSV-1 can still spread through microscopic viral shedding, even when the skin looks normal.² The following tips can help to reduce transmission risk:

• Avoid physical contact when a cold sore is active.

• Use a cold sore cream or antiviral treatment as early as possible.

• Protect lips and eyes from sun exposure.

• Avoid sharing utensils, lip balm, or towels.

• Practise barrier protection during oral-genital contact.³

If you’re looking for more specific advice on genital herpes, a great place to check is the Australian STI guidelines. They’ve got all the latest info and clear steps on what to do next.³

No. But they’re often confused. Here's what makes them different:

Cold sores:

• Caused by HSV-1

• Appear outside the mouth (lips, skin)

• Are contagious

Canker sores (mouth ulcers):

• Not viral

• Appear inside the mouth

• Not contagious

Canker sores may reflect immune imbalance, nutrient deficiencies, or autoimmune activity. Ongoing mouth ulcers, especially with digestive issues or fatigue, should be reviewed by a healthcare practitioner.

You can’t remove HSV-1, but you can reduce how often it flares with certain nutrients, including lysine.

Lysine: a star nutrient for cold sore prevention

Viruses like cold sores depend on an amino acid called arginine to multiply. Lysine is its natural rival. When you have plenty of lysine in your system, it competes for the same space the virus uses to process arginine. By shifting that balance, you’re effectively cutting off a resource the virus needs, which can help slow down the outbreak or keep it from getting worse. Research has shown that:

• Daily lysine intake of 1,200–1,248 mg for 5–6 months reduced cold sore recurrence by up to 1.7 times.⁴

• Best results occurred alongside a low-arginine diet (limiting nuts, chocolate, cereals, beer).⁴

This is why Metagenics Lysine Shield can be a useful option for overall immune support.

Yes. Especially when they support immune resilience. Also found in Metagenics Lysine Shield, these nutrients can help with tissue healing.

Vitamin C + Zinc

• Vitamin C boosts antiviral natural killer (NK) cell activity and wound healing.⁵

• Zinc supports immune signalling and tissue repair within 24 to 48 hours.⁶

• Low zinc levels are linked to longer HSV-1 healing times.⁶

• 1,000 mg vitamin C + 10 mg zinc daily supports faster recovery.⁷

Astragalus

Astragalus is an immune-supportive herb especially helpful during chronic stress.

• 1,000 mg daily improved immune activity in stressed or immunosuppressed individuals.⁸

• Enhances memory T-cells and improves HSV-1 lesion healing in studies.⁹

These ingredients combined within Metagenics Lysine Shield are a useful option for people with frequent, stress-triggered immune issues.

Quality Sleep

Quality sleep is a biological necessity for your immune system. During rest, your body produces cytokines, which are protective proteins that help target infections. When you’re sleep-deprived, your cytokine production drops, making you much more vulnerable to a flare-up.¹⁰

Stress management

Chronic stress alters immune signalling and can create an “anergic” (under-responsive) immune state.¹¹ Mindfulness, gentle exercise, and boundaries matter more than most people realise. Chronic stress does more than just make you feel tired; it actually alters your immune signaling. It can push your immune system into an "anergic" state, meaning it becomes under-responsive to threats. Practices like mindfulness and setting healthy boundaries are clinically relevant tools for keeping your immune defenses active.

Blood sugar balance

There is a direct link between glucose and inflammation. While blood sugar naturally rises during an infection, consuming too much refined sugar can stimulate inflammatory T-cells. This extra inflammation can make cold sore symptoms feel more severe and potentially drag out the healing time.¹²

Sun protection

UV radiation is a well-documented physical trigger for HSV-1. UV rays can suppress local immune function in the skin, allowing the virus to "wake up." Using a dedicated lip SPF, wearing hats, and using UV-protective sunglasses are essential preventative measures.

Maintain Vitamin D Levels 

Vitamin D plays a critical role in "training" your immune cells to respond correctly. Research has shown that low levels are often linked to more frequent outbreaks and slower recovery. Ensuring you have adequate Vitamin D is one of the simplest ways to support long-term prevention.¹³ 

It deactivates the virus, especially when applied early, helping to:

• Shorten healing time

• Reduce pain and blister size

• Lower viral activity at the skin surface

Think of cold sore creams and immune support as a two-pronged strategy: while the cream handles the surface, your immune system manages the virus from the inside. Using them together is usually the most effective way to shorten an outbreak and get your skin back to normal.

At the end of the day, a cold sore is more than just a spot on your skin; it’s a signal from your immune system. By keeping an eye on triggers like stress, sleep, and sun exposure, you can actually take back control. Combining a good cold sore cream with targeted support like lysine, zinc, and vitamins C found in Metagenics Lysine Shield can make a clear difference. For advice tailored specifically to you, it's always a good idea to chat with a healthcare professional.