Salt (sodium chloride) can heal cold sores faster due to its ability to dry out the fluid-filled blisters. It removes all of the moisture from a cold sore and minimizes viral shedding. Unfortunately, the drying process introduces the possibility of cracking, which could prolong the recovery process. Let’s find out if putting salt on cold sore overnight helps.

Knowing when to put salt on a cold sore overnight can be the difference between healing and intense burning or skin damage.

In this guide, you will find out how to apply salt to a cold sore. You’ll also discover other ingredients that can be added to sale to optimize the effectiveness. We’ll also take a close look at whether salt is a good or bad part of your day-to-day diet.

Why Put Salt on a Cold Sore Overnight?

Salt or sodium chloride can be an effective cold sore healer because it serves as an antiseptic. While it can potentially harm your skin, it is also a sound home remedy. It halts the sore’s development and dries out the site of the cold sore. This process is what transpires when you pour salt over ice.

  • Example: Salt being poured over a snowy and icy road during extreme winter weather conditions. The salt suppresses the moisture and dries out the surface area. Salt serves the same function when drying out a thriving cold sore. It can put an end to viral replication thus snuffing out the lifespan of the blister itself.[1] Without warm moisture, a cold sore will not survive.

Although salt can lead to some troublesome side effects, burning and potential skin damage being two, it is safer than most alternative treatments.

How Long To Leave Salt on a Cold Sore?

The duration of a cold sore salt treatment is a matter of personal preference. Some remedies can last hours while others just seconds. So much will depend on your tolerance for any discomfort (burning) and the extent (coverage area) of your blisters.

The use of powdered salt will make the session more comfortable. The finer the texture, the easier it will be to apply. Large salt crystals are NOT a good treatment option.

Below is an overview of the application process and what to expect during treatment:

  • Using powdered salt, gently apply it to a cotton swab. You can either moisten the swab with a drop of water or wet your index finger with water. It is critical that you wash your hands before dabbing a small amount of salt. Any bacteria that lives on your hands will contaminate the salt.
  • Once the salt has been applied to the swab, gently dab the cotton on the problematic area. Be sure to avoid a rubbing or scrubbing motion. This can irritate the blister. If you are in the midst of the scab stage, any rubbing could cause the scab to peel off. Be gentle with the application. Moistened powdered salt will stick to your blister, so you don’t need to be overly aggressive.
  • How long it remains in place is up to you. If you can avoid touching the area, you can let the salt absorb the moisture of the sore for hours. This would be the definition of an overnight cold sore treatment. On the other hand, salt is rather potent. Keeping the salt in place for only 60 seconds can be beneficial. If this is your plan, apply the salt, wait one minute, and then rinse the area with warm water.

You can repeat the process several times per day. You’ll observe visual cues that it is losing moisture. At that time you can stop treatment.

Should You Dry Out a Cold Sore Blister with Salt?

While using salt to dry out your cold sores should never be your first option. Although salt can be beneficial, it is just an alternative to proven over-the-counter medications.

Always use caution when using an alternative remedy. Salt can cause pain if used on an open wound, so it should be avoided.

If you have dealt with years of recurring cold sores, the use of salt is worthy of your consideration. However, if you are in the midst of your first outbreak, we do not recommend this treatment. FDA approved OTC treatments should always be your first plan of action. This is critical if you are dealing with your initial blisters.

Is a Salt Water Rinse Better than Applying Dry Salt?

Using a salt water rinse rather than dry salt is a personal preference. There is no right or wrong answer.

The only distinction is that a rinse will be less abrasive. Because the salt is mixed with water, the application will be less harsh.

Unless extremely diluted, a salt water rinse will still introduce antiseptic properties and positive benefits. The final results should be similar to that of dry salt since the primary objective is drying up the fluid in the blister.

If you are concerned about the potential for pain with a dry salt application, a rinse could be a better option.

To summarize:

  • Applying a salt water rinse rather than dry salt is less abrasive. This will likely reduce any threat of burning.
  • While diluting the salt is wise you want to avoid using too much water. Salt is the dominant player in this treatment plan. Diluting the salt too much will diminish the potency of the remedy. It is essential that you have enough salt content in the rinse.

Does Salt Work Better With Toothpaste?

The combination of salt and toothpaste can be beneficial as an overnight cold sore healer.

While it is understood that salt can serve as an antiseptic that can dry out cold sores, toothpaste has a similar quality. Courtesy of sodium lauryl sulfate, an active ingredient in toothpaste, your daily teeth cleaner can also heal your fever blisters.[2]

Sodium lauryl sulfate not only can dry out sores but also numb any pain while preventing virus replication. Combined with salt, a remedy can be formed to help heal your fever blisters.

salt on cold sore overnight

Noted below is a brief explanation of the application process.

  • Mix a small amount of powdered salt with toothpaste. Used just enough paste to cover the problem area. It is vital that you wash your hands before mixing/applying this treatment.
  • By using a cotton swab or a clean finger, gently apply the salt/paste remedy to your blister. Do not rub the area but instead lightly dab. Thin layer application is best.
  • This mixture is ideal for an overnight treatment. If the layer is thin enough, it should be able to last during the overnight hours. This will allow you to receive quality treatment while you sleep.
  • Rinse away the application with warm water the following morning.

Can the Salt in Food Cause Cold Sores? 

While salt can be used to treat cold sores, it can also be a cold sore trigger. This is one of the reasons why salt can be problematic.

  • Important: Concerning food consumption, salt can halt the natural healing process of a cold sore. Salt ingested acts differently than salt on contact with the skin. Salt placed on a sore can dry it out while salt in your diet can serve to trigger HSV-1.

From a general health standpoint, you should always strive to limit your salt intake. Too much salt in your diet can lead to increased blood pressure as well as a host of other health issues.

Having good health can help you to fend off a cold sore outbreak. Weak immune health can trigger an outbreak while a healthy and robust system can prevent fever blisters.[3]

You should make it a point to manage your salt intake. Not only as a means to prevent cold sores but as a good plan for healthy living.

To recap:

  • A diet that is high in sodium can trigger the herpes simplex virus and also harm the natural healing process of existing sores.
  • While salt used as a cold sore treatment can dry out blisters, a diet high in salt can be counterproductive.
  • It is always important to keep your immune system and general health in top working order. This can help to prevent fever blister outbreaks. Introducing a diet that is low in salt will be beneficial in the big picture.

Salt can provide relief. If applied responsibly, salt can heal your cold sore days earlier than would otherwise be the case.

Although there is a risk of burning (upon application) as well as skin damage, these side effects can be remedied. Once your sore has been diminished, it is vital that you rejuvenate your lip with a moisturizing balm. This will help return your lip and skin to a healthy state. I hope our article helped you understand if putting salt on cold sore overnight helps.


  1. Utsunomiya H, Ichinose M, Tsujimoto K, et al. Co-operative thermal inactivation of herpes simplex virus and influenza virus by arginine and NaCl. International Journal of Pharmaceutics. 2009;366(1-2):99–102.
  2. Piret J, Lamontagne J, Désormeaux A, Bergeron MG. Efficacies of Gel Formulations Containing Foscarnet, Alone or Combined with Sodium Lauryl Sulfate, against Establishment and Reactivation of Latent Herpes Simplex Virus Type 1. Antimicrobial Agents and Chemotherapy. 2001;45(4):1030-1036. doi:10.1128/AAC.45.4.1030-1036.2001.