Table of ContentsView AllTable of ContentsWhat Are Antihistamines?Can Antihistamines Cause Weight Gain?What Causes Weight GainDrugs With Most Likely EffectsDrugs With Least Likely EffectsPreventing Weight Gain
Table of ContentsView All
View All
Table of Contents
What Are Antihistamines?
Can Antihistamines Cause Weight Gain?
What Causes Weight Gain
Drugs With Most Likely Effects
Drugs With Least Likely Effects
Preventing Weight Gain
Antihistaminescan be great at relieving allergy symptoms such as sneezing, runny nose, and itchy, watery eyes. While the drugs are generally regarded as safe, they are not without side effects.
One possible side effect—and one that people don’t often think about—is the risk of weight gain with over-the-counter antihistamines likeAllegra(fexofenadine) andZyrtec(cetirizine).
This article explores differing views on whether antihistamines cause weight gain and offers some research insights and possible explanations for why weight gain can occur.
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Antihistamines are medications that are commonly used to treat allergy symptoms due to conditions like:
When histamine is released as part of an allergic response, it can cause itching, rash, breathing problems, and other adverse symptoms.Histamine is the primary cause of allergy symptoms.
Antihistamines for Nasal Allergies
Some studies of weight gain and its relationship to antihistamine use find there’s a pattern of association, but it’s not entirely clear why.
Weight gain may be linked to changes inlymph flowthat affectlipids(fats) and digestive absorption. Bothobesityand metabolic syndromes (like metabolic dysfunction-associatedsteatoticliver disease, orMASLD) may arise from the effect of long-term antihistamine use.
These conclusions from a 2020 study, published in the journalChildren,also found that prolonged antihistamine use in children was associated with a two-fold increase inbody mass index(BMI) per year compared to kids who didn’t take antihistamines.
BMI is a dated, flawed measure. It does not take into account factors such as body composition, ethnicity, sex, race, and age. Even though it is a biased measure, BMI is still widely used in the medical community because it’s an inexpensive and quick way to analyze a person’s potential health status and outcomes.
Older antihistamines, such asBenadryl (diphenhydramine), are known to cause significant side effects such as drowsiness.
Newer antihistamines, like Allegra, were seen to be an advance in treatment, alleviating symptoms without the accompanying drowsiness. Even so, newer antihistamines like Allegra and Zyrtec are known to cause side effects like:
According to a landmark 2010 study published in the journalObesity,people who regularly take antihistamines are more likely to beoverweight or obesethan those who do not.
With 268 antihistamine users involved in the study, their prolonged use was associated with a roughly 10% increase in weight,body mass index (BMI), and waist circumference. The risk was seen to be greatest with newer-generation drugs like Allegra, Zyrtec,Claritin(loratadine), Clarinex (desloratadine), and Xyzal (levocetirizine).
However, other experts suggest that factors like small sample size and the age of the study raise questions about the results. They suspect that Allegra, Claritin, and other newer drugs are less likely to cause weight gain than Periactin (cyproheptadine) and other first-generation drugs.
Why Do Antihistamines Cause Weight Gain?
Other scientists contend antihistamines more directly act on cells and processes in the body. A 2019 study from Texas A&M University suggests the prolonged use of Clarinex is associated with an increased risk of high cholesterol, high blood sugar, andinsulin resistance.
When Antihistamines Stop Working
Which Antihistamines May Cause Weight Gain?
Some studies find evidence that the newer (second-generation) antihistamine drugs are more likely to lead to weight gain. These drugs include:
In some cases, drugs with antihistamine properties may be used intentionally to cause weight gain. That’s the case, for example, with some antihistamines used to stimulate appetite in people diagnosed withcystic fibrosis. These drugs include:
Some antihistamines are used to treat nausea and vomiting (including morning sickness) ormotion sickness(as with Benadryl). They may limit weight loss due to symptom relief.
Which Antihistamines Are Least Likely to Cause Weight Gain?
Although researchers find evidence for weight gain with some of the newer antihistamines, the older drugs are still associated with weight gain. Whether or not you gain weight with certain drugs also depends on many other factors, including the use of other medications.
Generally speaking, newer drugs like Allegra and Claritin may even be less likely to cause weight gain than earlier drugs like Periactin, but research results are mixed.
How to Prevent Weight Gain From Antihistamines
Talk to your healthcare provider about whether the antihistamines you take are leading to weight gain or increased risk. They may be able to change a medication or dosage.
You also can follow generallifestyle habitsmeant to help people maintain a healthy weight. These include:
You also can try alternatives to antihistamines, such asvitamin C,probiotics,acupuncture, ornasal irrigation.
Mindfulness Exercises for Anxiety and Stress
Summary
Antihistamines are a class of drugs that are used to treat allergy symptoms. While newer-generation antihistamines like Allegra and Zyrtec are less likely to cause drowsiness than older drugs like Benadryl, there’s less clarity about an increased risk of weight gain in some users.
Some studies suggest that the prolonged use of newer-generation antihistamines can significantly increase body weight and waist circumference compared to people who don’t use antihistamines. Even children who take antihistamines appear to be affected.
12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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