• Allergies

How To Increase Sublingual Absorption

Medically reviewed and edited by Payel Gupta, MD, FACAAI

Published: November 25, 2021
Updated: March 14, 2025
13 mins

If you’re dealing with seasonal allergies, sublingual allergen immunotherapy is one treatment you need to know about.

Immunotherapy is an allergy treatment that allergists have recommended for decades, especially for people with stubborn allergies who won’t respond to other medications. While there are two types of immunotherapy – sublingual and subcutaneous – we’ll be focusing solely on taking steps to find relief from sublingual treatments.

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First Off: What Is Sublingual Medication?

Sublingual medication is taken by placing a tablet, drops, or lozenges under your tongue and letting it dissolve. After dissolving, the medication works by absorbing into the bloodstream.

Types of Sublingual Medication

Several different types of medication can be taken sublingually. They include:

• Tablets: They melt in your mouth and are commonly used for managing symptoms like nausea, vomiting, and allergies.

• Lozenges: They dissolve in your mouth and are often flavored. Lozenges are often supplements rather than prescription medication, sometimes containing minerals like zinc.

• Sublingual drops: This is the type of sublingual medication normally used to treat allergies.

Sublingual Allergy Treatments Explained

One of the most common uses for sublingual medication is allergy immunotherapy. This treatment method is often recommended for those with chronic seasonal allergies who don't see improvements with other medications.

When a patient gets treated for allergies with sublingual immunotherapy, treatment aims to lower the immune system’s sensitivity to specific allergens. Immunotherapy medication contains small amounts of the patient’s allergy triggers. These allergens are absorbed into the bloodstream when each dose is taken.

The idea of taking medication that contains allergens might sound counterproductive, but there’s a reason behind it. Gradually exposing the immune system may help it adjust to certain allergens.

By slowly increasing exposure, allergy symptoms should gradually decrease and, eventually, go away.

Why Sublingual Immunotherapy?

Sublingual immunotherapy is often recommended to those with allergies due to its convenience, accessibility, and effectiveness.

In contrast to other treatments like subcutaneous immunotherapy (allergy shots), sublingual treatment tends to have a lower risk of side effects. Because of the minimal risk of an adverse reaction, sublingual immunotherapy is considered a safe treatment for at-home use.

While both allergy shots and sublingual immunotherapy are thought to be highly effective treatment strategies for allergies, one requires significantly more time and effort than the other.

Shots are effective and reliable, but getting them means frequent visits to the doctor's office. In addition, the cost of subcutaneous immunotherapy treatments can sometimes be higher.

In contrast, sublingual immunotherapy is safe to take at home, has a low risk of side effects, and is sometimes covered by medical insurance.

Is Immunotherapy Safe?

The short answer to this question is yes.

When you start taking immunotherapy treatments by mouth or getting allergy shots, your allergist will fill you in on all of the potential side effects that you might experience during the treatment process. However, these side effects are highly unlikely, and your allergist will prepare you to respond if an adverse reaction occurs.

Because immunotherapy works by exposing your body to allergens, there’s always the possibility that symptoms will arise after receiving treatment. However, the reaction that might occur following the administration of immunotherapy medication isn’t likely to pose a severe threat to your health.

Severe adverse reactions to immunotherapy are more closely associated with subcutaneous treatment (shots) than sublingual medication. This increased risk of side effects is one of the main reasons why allergy shots have to be administered in an allergist’s office for treatment.

Sublingual immunotherapy comes with a much lower risk of an adverse reaction, and sublingual treatments can be taken at home without the supervision of an allergist. However, it’s always a good idea to let your allergist know if any unexpected side effects develop at any point during treatment.

The Pros and Cons of Sublingual Medication For Allergies

There are plenty of reasons to try sublingual immunotherapy treatments for allergies, but there are also potential cons to consider.

The pros

Some of the major perks of sublingual allergy immunotherapy include:

• They produce faster results: Studies of sublingual medications have shown that these medications absorb into the bloodstream for quicker results.

• You can take sublingual treatments without supervision: In contrast to allergy shots, your sublingual allergy immunotherapy treatments can be taken at home without being overseen by an allergist. That means less commuting and medical bills than you would deal with while undergoing subcutaneous immunotherapy treatments.

• Sublingual treatments seem to produce long-term results: Both types of immunotherapy are intended to help you manage your allergies in the long run and even stop dealing with them entirely.

In some cases, consistent immunotherapy treatments for months or years may eliminate the need for over-the-counter and prescription treatments like antihistamines.

The cons

Some potential drawbacks to immunotherapy for allergies are:

• It doesn't work for everyone: Immunotherapy treatments don’t work for all types of allergies. This type of treatment can’t mitigate reactions caused by food or medication. The treatment is typically used to help patients who have asthma and allergic rhinitis (hay fever).

• Long-term effects may take a while: This is as much of a pro as a potential con, but allergy immunotherapy takes a long time to work. You’ll have to be patient as you continue treatment over months and even years.

However, you’re likely to see major improvements in the severity of your allergy symptoms long before treatment is complete.

Factors That Can Affect the Effectiveness of Sublingual Immunotherapy

If immunotherapy treatments haven’t been successful so far, a healthcare provider may suggest tips for making the treatment effective or other options.

Taking the medication incorrectly

Sometimes, you might be tempted to eat, drink, or chew gum immediately after taking your immunotherapy treatments. However, it’s best to wait until the treatment has been completely absorbed to put anything else in your mouth.

In addition, it’s essential not to swallow sublingual immunotherapy doses. Instead, let them dissolve under your tongue. Swallowing a dose of your immunotherapy medication is safe, but it dramatically decreases the effectiveness of the dose.

Exposure to other airborne irritants

While you might not be allergic to them, environmental triggers like smoke, dust, and more can exacerbate allergy symptoms during immunotherapy treatment. While these factors don’t necessarily make the treatment less effective, they can leave you feeling uncomfortable and worsen your allergies.

Consider limiting your exposure to air pollutants like smoke and dust as much as possible. In addition, equipping your home with a HEPA air filter or air purifier can help to maximize the air quality in your home.

Mouth sores and other types of oral inflammation

Open sores in your mouth, as well as other forms of mouth inflammation, can disrupt the absorption of immunotherapy medication. If you have a mouth ulcer, a sore, or an open cut in your mouth or gums, make sure to let your healthcare provider know before continuing treatment.

Smoking

Smoking — and using tobacco products, in general — can limit your ability to absorb sublingual medications effectively. Smoking constricts blood vessels, which reduces your body’s ability to effectively use medication that is absorbed into your bloodstream.

Smoking can also cause a wide array of other health problems, including an increased risk of lung cancer. Taking steps toward quitting smoking is the best possible solution because of its effects on a person's respiratory health.

Saliva pH balance

The acidity and alkalinity levels in your mouth can also affect your body’s ability to absorb and use allergy immunotherapy treatments. This is because your body’s ionization of sublingual medications is largely dependent on the pH in your mouth.

Drugs become ionized or charged in response to a certain level of acidity in your mouth, which can decrease the effectiveness of medication.

What you eat and drink can have a big impact on the acidity levels inside your mouth. That’s why it’s recommended that you avoid eating or drinking anything shortly before and after taking each dose of your immunotherapy medication.

Mouth dryness

When there is plenty of saliva in your mouth, your sublingual immunotherapy treatments are more likely to be absorbed effectively. When your mouth is dry, it is more difficult for the medication to be absorbed into your bloodstream, as allergy drops are aided by saliva dissolving under your tongue.

Frequently Asked Questions About Sublingual Immunotherapy

What allergies can immunotherapy treat?

Immunotherapy treatments can be used to remedy several allergies, including:

• Pollen. Pollen typically causes seasonal or perennial allergy symptoms. For most people with pollen allergies, the main culprits are certain trees, flowers, and weeds. You’ll need a specific immunotherapy treatment for each type of pollen that you are allergic to.

• Mold. Mold allergies can cause symptoms internally and externally. Immunotherapy treatments can offer a long-term source of relief for those with mold allergies. Still, try to avoid mold-contaminated areas as much as possible to keep symptoms to a minimum.

• Dust mites. These microscopic creatures dwell indoors in carpets, upholstery, and sheets, feeding on the dead skin cells left behind by humans. For some, the waste left behind by dust mites leads to an allergic reaction, which long-term immunotherapy treatments can mitigate.

• Pet dander. In some cases, allergen immunotherapy is recommended for those with pet allergies. However, avoidance and daily relief medications are more commonly used to manage pet allergy symptoms.

Is Immunotherapy Safe For Kids?

Immunotherapy treatments are often recommended for kids who have asthma or seasonal allergies.

While some children may get the relief they need from over-the-counter or prescription antihistamines, many kids need long-term, sustained immunotherapy treatments to get their allergy symptoms to a manageable level.

In many cases, kids are given subcutaneous immunotherapy treatments at an allergist’s office. However, if your child is afraid of needles, weekly or biweekly visits to the allergist for shots may not be the best option. Luckily, sublingual immunotherapy offers an easier and more accessible alternative to shots.

Sublingual immunotherapy treatments are safe for kids, and getting treated can be a much less stressful experience for children when needles are out of the picture.

What About Older Individuals?

Allergies are a common issue in those over the age of 65. If you are older and continue to experience allergy symptoms, immunotherapy is worth looking into as a treatment option.

However, allergy immunotherapy is not always the first treatment suggested to older people with allergies.

The main reason why doctors do not always recommend immunotherapy to older individuals is because of more glaring health issues. A healthcare provider may want to focus more on finding treatments for more severe conditions than allergies.

Finding a treatment that works for older individuals with allergies can positively impact their quality of life. Even if you have other health conditions with more severe symptoms, getting relief from your allergies can make a big difference in your life at any age.

Do Immunotherapy Treatments Taste Like Anything?

Some allergy drops are slightly flavored with vegetable glycerin, which gives each dose a mildly sweet taste. Some people may enjoy the flavor.

Whenever you take a dose, you’ll need to hold it in your mouth for about a minute, allowing it to dissolve.

How Long Does Treatment Last?

In many cases, people with seasonal allergies need to continue sublingual immunotherapy treatments for several years. In the early stages of treatment, your body will still be getting used to increased exposure to allergens.

The buildup process to a higher dose of your immunotherapy treatment can take time, so it’s important to be patient and not give up on the treatment – even if you do not see results yet.

Compared to subcutaneous immunotherapy, allergy drops typically need to be taken for about the same amount of time. Like sublingual treatments, allergy shots are usually administered over a period of several years, starting with an incremental increase in dosage and working up to a maintenance dose.

That means that whichever immunotherapy treatment you choose, the timeframe for the treatment process will be several years.

After your immunotherapy treatments are complete, you’re likely to see a significant reduction in your allergy symptoms – or have no noticeable symptoms at all. In addition, longitudinal studies of immunotherapy results have shown that improvements can last for at least several years without any additional allergy treatments.

While immunotherapy is a time commitment and an investment, it’s also one of the most effective treatment options for people with stubborn seasonal allergies. If your symptoms aren’t going away in response to other medications, it’s time to consider sublingual allergen immunotherapy as your next step.

Conclusion

When it comes to finding long-term relief for your allergies, immunotherapy is one of the best treatment options out there. While allergy shots are an effective form of immunotherapy, they can be more costly and time-intensive than sublingual treatments.

Health experts recommend trying sublingual immunotherapy as a remedy for stubborn allergy symptoms – it’s affordable, accessible, and can be taken in the comfort of your home.

At LifeMD, you can speak with a licensed healthcare provider about what to do if you are experiencing intense allergy symptoms. They can provide you with treatment options like sublingual absorption and tips for treating severe allergy symptoms.

Book an appointment today to learn more about treatment options for severe allergy symptoms.

Payel Gupta, MD, FACAAI

Dr. Gupta holds certifications from the American Board of Allergy and Immunology, American Board of Internal Medicine, and American Board of Pediatrics. With a deep interest in global health, she’s volunteered her clinical skills across many continents.

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