Peanut Allergy Treatment Shows Promise in Adults

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On April 25, 2025

Preliminary results from a small, first-of-its-kind clinical trial have shown that gradually exposing adults with a peanut allergy to small doses over time — a method already used to desensitize children — can help them build up a tolerance and lower their risk of life-threatening reactions.

For those who are allergic to peanuts, even a miniscule amount might trigger a severe reaction called anaphylaxis, which causes difficulty breathing, swelling of the throat or tongue, a sudden drop in blood pressure, and loss of consciousness.

Previous research has shown that allergic children can raise their tolerance by gradually increasing daily peanut consumption, a technique experts call oral immunotherapy.

The new trial, the first to test this approach in adults, found that two-thirds of participants could eat the equivalent of five peanuts without reacting after slowly increasing the amount they eat over several weeks under medical supervision.

“This trial provides preliminary evidence that adults can be desensitized and that this improves quality of life. The average tolerated dose of peanuts increased 100-fold over the course of the trial,” said study author Stephen Till, MD, PhD, professor of allergy at King’s College London in England, in a press release.

Edwin Kim, MD, an associate professor of pediatrics at the University of North Carolina and director of the UNC Food Allergy Initiative in Chapel Hill, views these results as a step forward because they show that oral immunotherapy can be an effective option for peanut allergy regardless of age.

“It does come with risk and can be difficult to do, so it should be discussed with your allergist to see if the benefit outweighs the risk, and if it might make sense for the patients,” says Dr. Kim, who was not involved in the research.

Some Study Subjects Eventually Tolerated 5 Peanuts a Day

For the trial, scientists from King’s College London and Guy’s and St Thomas’ NHS Foundation Trust recruited 21 individuals between the ages of 18 and 40 with a diagnosed peanut allergy.

Participants received an initial dose of 0.8 mg peanut flour mixed in with food, then roughly doubled the amount (1.5 mg) 30 minutes later, followed by another doubling to 3 mg an additional 30 minutes later.

Those who tolerated the initial 1.5 mg or 3 mg of peanut flour continued on a daily dose at home for two weeks. The dose was the equivalent of 0.5 to 1 percent of a whole peanut.

Then participants returned every two weeks for supervised doses of more peanut protein, increasing from 6 mg (about 2 percent of a whole peanut) to 1 gram (g), or four whole peanuts.

If participants could tolerate 50 to 100 mg of peanut protein, they were switched to eating whole peanuts, peanut butter, or peanut products, with the first dose administered under supervision of the clinical team.

Once participants reached a daily dose of 1 g without reaction, they remained on this dose or higher for four weeks. They continued daily dosing at home for at least three months.

The results, published this week in the journal Allergy, showed that by the end of the study, 14 of the 21 participants (67 percent) tolerated eating at least five peanuts a day (1.4 g).

The study authors noted that 95 percent of problematic reactions during the trial were mild.

Living With Peanut Allergy Can Cause Serious Distress

Peanut allergy is one of the most common food allergies in the United States, affecting an estimated 4.6 million adults.

Kim says that patients with peanut allergy often have a never-ending fear that they may eat the wrong thing, such as a food that is cross-contaminated or mislabeled.

This fear can lead to social isolation and avoiding activities that others take for granted, such as eating out and attending parties.

“Constant fear of life-threatening reactions places a huge burden on people with peanut allergy,” noted study author Dr. Till in the press release.

Recognizing Limitations and Other Treatments

The trial results are limited because of the small number of participants and relatively short follow-up time. Further studies expanding to larger groups over a longer time period will be needed to demonstrate how truly effective this approach may be, according to Joao Pedro Matias Lopes, MD, an assistant professor of pediatrics at Case Western Reserve University School of Medicine in Cleveland.

“No one can guarantee this approach is long-lasting,” says Dr. Lopes, who was not involved in the study. He adds that this is not a cure and peanut allergy can come back once it “goes away.” Maintaining a tolerance for peanuts may require continued adherence to daily peanut consumption throughout a person’s life.

Other treatments for peanut allergy include:

“It is great to get data showing success in protection from life-threatening peanut allergies in adults, but we still have a lot more work to do and the problem is very complex,” says Lopes.