Does Valtrex Help Canker Sores?

Does Valtrex Help Canker Sores

Valtrex, also known as valacyclovir, is a prescription medication primarily used to treat herpes simplex virus infections, including genital herpes and cold sores.

However, some people also use Valtrex for canker sores or aphthous ulcers.

In this article, we will explore whether or not Valtrex is an effective treatment for canker sores.

What are Canker Sores?

What are Canker Sores?

Canker sores, also known as aphthous ulcers, are small shallow lesions that form on the soft tissues inside the mouth.

They can be painful and can make it difficult to eat or talk. Canker sores typically go away on their own within one to two weeks, but in some cases, they may last longer.

The Different Types of Canker Sores

Three primary categories of canker sores exist:

  • Simple canker sores are the most common type and usually appear 1-2 times a year in individuals aged 10 to 20.
  • Complex canker sores are less common and occur more often in people who have previously had them.
  • Herpetiform canker sores are pinpoint size and often occur in clusters of 10 to 100.

Causes of Canker Sores

Canker sores can have a multitude of causes:

  • Minor mouth injuries from dental procedures, vigorous brushing, sports accidents, or accidental biting
  • Food allergies or sensitivities
  • Hormonal fluctuations during the menstrual cycle or pregnancy
  • Emotional pressure
  • Bacterial or fungal infections

The exact cause of most canker sores is still uncertain, but they are frequently associated with a combination of these factors.

Symptoms of Canker Sores

The symptoms of canker sores include:

  • Small, round, or oval-shaped sores with a white or yellow center and a red border
  • Painful mouth ulcers
  • Tingling or burning sensations prior to the sores’ emergence
  • Difficulty speaking, eating, drinking, or brushing teeth due to pain

Can Valtrex Help Canker Sores?

The short answer is no.

Valtrex has not been approved by the FDA for the treatment of canker sores, and there is limited evidence that it is effective in treating them.

Valtrex works by stopping the growth and spread of the herpes virus, but canker sores are not caused by a virus.

Benefits of Using Valtrex for Canker Sores

Despite the fact that Valtrex is not approved for treating canker sores and lacks strong evidence in this regard, there are some perceived benefits when it’s used off-label for canker sores:

  • May Reduce Symptom Severity: Some believe Valtrex may help to decrease the severity of symptoms if taken at the very onset of a canker sore outbreak.
  • Possible Reduction in Healing Time: There’s anecdotal evidence suggesting Valtrex might slightly reduce the time it takes for canker sores to heal.
  • Pain Management: By potentially affecting the course of the canker sore, users report experiencing less pain during the healing process.

It’s important to consult a healthcare provider before using Valtrex for canker sores, considering these points lack strong clinical support.

Also Read: Can Valtrex (Valacyclovir) Lead to Hair Loss?

Side Effects of Using Valtrex for Canker Sores

Side Effects of Using Valtrex for Canker Sores

Like many medications, Valtrex can have side effects. While it might present certain benefits for canker sores, users should be aware of potential adverse reactions, especially when used without the guidance of a healthcare provider:

  • Gastrointestinal Issues: Some users might experience nausea, stomach pain, or vomiting.
  • Dizziness and Headaches: These are common side effects that could affect daily activities.
  • Kidney Issues: In rare cases, Valtrex can lead to serious kidney issues, particularly in those with preexisting conditions.
  • Allergic Reactions: Though rare, some individuals may have an allergic reaction to Valtrex, characterized by rash, itching, and swelling.

It’s important to consult a healthcare provider to determine if using Valtrex off-label for canker sores is worth the risks.

Also Read: Pros and Cons of Taking Valtrex Daily

How to Use Valtrex for Canker Sores

  • Dosage

If a healthcare provider does recommend Valtrex for canker sores, the typical dosage is 2000 mg taken twice daily for one day.

This may be followed by an additional 1000 mg taken once daily for one to three days.

  • Precautions

Before using Valtrex for canker sores, it’s essential to discuss any preexisting conditions and medications with a healthcare provider.

Valtrex can interact with certain medications like nonsteroidal anti-inflammatory drugs (NSAIDs), leading to potential kidney issues.

It’s also important to disclose any allergies to the medication or its ingredients.

Also Read: Can Valtrex Cause a Yeast Infection?

How Long Does Valacyclovir Take to Work for Canker Sores?

If a healthcare provider does recommend Valtrex for canker sores, it should start to work within 24 hours of taking the medication.

However, this may vary from person to person based on factors such as overall health and severity of symptoms.

It’s important to follow the recommended dosage and complete the full course of treatment for best results.

What is Valtrex (Valacyclovir)?

What is Valtrex (Valacyclovir)?

Valtrex is an antiviral medication that contains the active ingredient valacyclovir.

It works by stopping the growth and spread of the herpes virus, which causes cold sores, genital herpes, and shingles.

  • Mechanism of Action

Valacyclovir is converted into acyclovir in the body, which then stops the herpes virus from reproducing.

This ultimately helps to reduce the severity and duration of symptoms associated with herpes viruses.

  • Approved Uses and Off-Label Uses

Valtrex is approved by the FDA for the treatment of cold sores, genital herpes, and shingles.

Some healthcare providers may prescribe it off-label for other conditions, such as canker sores, but this is not a recommended use.

Also Read: Can Valtrex Lead to Weight Gain?

Alternative Treatments for Canker Sores

While Valtrex is not a recommended treatment for canker sores, individuals looking for relief may consider several alternative treatments that can help manage symptoms and potentially speed up the healing process:

  • Topical Products:

Over-the-counter topical products containing numbing agents or ingredients like benzocaine, lidocaine, or menthol can provide temporary relief from pain and discomfort associated with canker sores.

  • Home Remedies:

Rinsing with salt water or baking soda and water mixture to help reduce pain and inflammation.

Applying a wet tea bag to the sore for 5-10 minutes to soothe the area.

Consuming foods that are easy to swallow, such as smoothies, soups, and purees.

  • Oral Medications:

Over-the-counter pain relievers like acetaminophen or ibuprofen can help manage pain associated with canker sores.

Your healthcare provider may also prescribe an oral steroid to reduce inflammation and speed up healing.

  • Nutritional Supplements:

Some individuals have found relief from canker sores by supplementing with vitamins B12, zinc, and folic acid.

  • Prevention Strategies:

Avoiding foods that irritate the mouth including spicy, acidic, or sharp-edged foods.

To avoid minor injuries that may cause sores, maintain good oral hygiene and use a toothbrush with soft bristles.

Managing stress through relaxation techniques, as stress can trigger outbreaks in some individuals.


Valtrex may provide some relief for canker sores, but it’s not an approved treatment and lacks strong clinical support.

Before using Valtrex off-label for canker sores, individuals should consult a healthcare provider to discuss potential risks and benefits.

Key Takeaways

  • Valtrex may help decrease the severity and healing time of canker sores, but it lacks strong clinical support.
  • Common side effects of using Valtrex for canker sores include gastrointestinal issues, dizziness, headaches, and rare kidney issues or allergic reactions.
  • If recommended by a healthcare provider, Valtrex is typically taken at a dosage of 2000 mg twice daily for one day, followed by 1000 mg once daily for one to three days.
  • Alternative treatments for canker sores include topical products, home remedies, oral medications, nutritional supplements, and prevention strategies.
  • It’s important to follow recommended dosages and complete the full course of treatment for best results.

Frequently Asked Questions (FAQs)

How can I get a prescription for Valtrex to treat my canker sores?

Valtrex is not an FDA-approved treatment for canker sores, so it’s important to discuss potential risks and benefits with a healthcare provider before considering its use.

If your healthcare provider does recommend Valtrex off-label for canker sores, they can provide you with a prescription.

Can I buy Valtrex over the counter?

No, Valtrex is not available over the counter. It requires a prescription from a healthcare provider.

Does antiviral help canker sores?

Antiviral medications like Valtrex are not recommended for treating canker sores.

However, they may be prescribed in certain cases if a healthcare provider determines the potential benefits outweigh the risks.

Can I prevent canker sores?

Yes, some individuals have found success in preventing canker sores by managing stress levels, avoiding trigger foods, and maintaining good oral hygiene.

However, there is no guaranteed way to prevent canker sores entirely.

Can Valtrex be used in combination with other treatments for canker sores?

There is limited research on the use of Valtrex in combination with other treatments for canker sores.

It’s important to discuss potential interactions and risks with a healthcare provider before combining any treatments.

Can Valtrex be used for treating canker sores in children or pregnant women?

Valtrex is not recommended for use in children under the age of 12 or pregnant women, as its safety and effectiveness have not been established in these populations.

If your child or you are pregnant and experiencing canker sores, consult a healthcare provider for appropriate treatment options.

Useful Resources:

Healthline- Are Canker Sores Herpes?

WebMD- Canker Sores

WebMD- Valtrex


The content of this article is provided for informational purposes only and should not be considered a replacement for professional medical advice, diagnosis, or treatment. It is important to seek professional medical advice and not disregard it or delay seeking it based on the information read here. While we strive to provide accurate and reliable information, we cannot guarantee its completeness, accuracy, reliability, suitability, or availability for any purpose. Using the information in this document is your responsibility and carries inherent risks. We are not liable for any losses or damages resulting from the use of our content.


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