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Does baking soda heal cold sores?

Cold sores, also known as fever blisters, are small blisters that develop on the lips or around the mouth. They are caused by the herpes simplex virus (HSV-1) and are very contagious. Cold sores typically last 7-10 days if left untreated. While no cure exists, several home remedies claim to help reduce pain and speed healing of cold sores, including baking soda.

What are cold sores?

Cold sores are fluid-filled blisters that develop on or around the lips. They are caused by infection with the herpes simplex virus type 1 (HSV-1). HSV-1 is very contagious and spreads through direct contact between broken skin and infected body fluids.

Many people get exposed to HSV-1 in childhood. The virus then lies dormant in nerve cells and can reactivate later, causing cold sores. Common triggers include:

  • Stress
  • Fatigue
  • Illness
  • Menstruation
  • Sun exposure
  • Skin trauma

The first signs of a cold sore are tingling, burning, or itching at the site where the blister will develop. Over the next 48 hours, small fluid-filled blisters will appear which continue to fill with fluid over 3-4 days. The blisters eventually burst open, ooze, crust over, and heal without scarring in 7-10 days.

What is baking soda?

Baking soda, also known as sodium bicarbonate or bicarbonate of soda, is a chemical compound with the formula NaHCO3. It is a white, crystalline powder that is soluble in water.

Baking soda has a variety of household and medical uses due to its neutralizing and gently abrasive properties. It can be used for baking, cleaning, deodorizing, and more. Some key properties of baking soda include:

  • Alkaline pH of 8.3, helping neutralize acids
  • Abrasive texture that helps remove dirt, oil, and residue
  • Antibacterial and antifungal properties
  • Odor neutralizing abilities

These attributes make baking soda a popular home remedy for many conditions. It is safe for oral consumption and topical use.

Can baking soda help heal cold sores?

There is limited scientific evidence regarding baking soda and cold sores specifically. However, some research and anecdotal evidence suggest it may help when applied topically:

May reduce swelling and inflammation

Baking soda is anti-inflammatory due to its alkaline nature. It helps neutralize acids that can accumulate in inflamed tissues. This may help reduce swelling, inflammation, and pain of cold sores.

May speed up healing

The slightly abrasive texture of baking soda may help remove virus particles from the skin surface. Its antiseptic properties may also prevent secondary bacterial infections. Together, this could help speed up healing.

May ease pain and itching

Baking soda is known to relieve pain and itching from insect bites, sunburns, and other skin irritations due to its anti-inflammatory effects. It may provide similar relief for the pain and itch of cold sores.

Anecdotal evidence

Many people report that applying baking soda to cold sores helps dry them out and reduces pain, swelling, and duration. However, high-quality clinical studies are still needed.

How to use baking soda on cold sores

To use baking soda on cold sores:

  1. Wash hands thoroughly to avoid spreading the virus.
  2. Mix a small amount of baking soda with just enough water to form a paste.
  3. Apply the paste directly to the cold sore using a cotton swab or clean fingers.
  4. Let it sit for 5-10 minutes before rinsing off.
  5. Repeat 3-4 times per day as needed for relief.

The paste can be reapplied whenever pain, swelling, or oozing recurs. Take care not to spread the paste onto unaffected skin as baking soda can cause dryness and irritation.

Alternatively, a baking soda bath can be made by dissolving 4-6 tablespoons of baking soda in a bowl of warm water. Soak a clean cotton pad in the solution and apply to the cold sore for 5-10 minutes 2-3 times per day.

Other home remedies for cold sores

In addition to baking soda, other home remedies may help speed up healing of cold sores. These include:

Remedy How It May Help
Ice Reduces pain and inflammation
Aloe vera Soothes pain and inflammation
Lemon balm Has antiviral and anti-inflammatory properties
Lysine Blocks the virus from replicating
Petroleum jelly Protects cold sores from irritation

When to see a doctor

See your doctor if:

  • It is your first cold sore outbreak
  • Cold sores are very large, painful, or swollen
  • Symptoms last longer than 2 weeks
  • Symptoms spread beyond the lip area
  • You have a weakened immune system
  • You experience signs of a bacterial infection like pus, fever, or increased swelling

Diagnostic tests can help confirm it is HSV-1 causing the cold sores. Antiviral medications like Valacyclovir are available by prescription if home remedies do not provide enough relief.


While no cure exists for HSV-1, you can take steps to avoid recurrent cold sore outbreaks including:

  • Using SPF lip balm when outdoors
  • Avoiding too much sunlight exposure
  • Managing stress levels with relaxation techniques
  • Getting adequate sleep and nutrients
  • Avoiding skin trauma such as lip biting or picking
  • Avoid sharing items like lip balm, cups, and utensils

Treatment at the earliest signs of tingling or itching may also help avoid progression to a full cold sore blister.


Baking soda may help reduce pain, inflammation, healing time, and duration of cold sores due to its anti-inflammatory and antiseptic properties. It is a popular home remedy for cold sores, though clinical studies are still limited.

When applied topically as a paste or solution, baking soda may help dry out cold sores, neutralize the virus, and speed healing. It is generally safe when used correctly, but can cause skin irritation in some people.

Baking soda can be used along with other remedies and medications to provide cold sore relief. See a doctor if symptoms are severe, last longer than 2 weeks, or you experience complications.

While baking soda treatment may help, the best approach is preventing outbreaks through avoiding triggers, using SPF, managing stress, and not sharing personal items.