1 Antihistamines can trigger weight gain.
According to a study from the Yale University School of Medicine, antihistamines—commonly used to treat spring allergies—are known to cause significant weight gain. The researchers reviewed medical data from 268 adults (174 female and 94 male) who reported the use of antihistamines and compared that data with that from 599 people (401 female and 198 male) who did not. They found that those who regularly used antihistamines “displayed significantly greater BMI, waist circumference, and insulin levels,” suggesting “a correlation between using antihistamines and a higher weight.” They determined that men who used antihistamines weighed an average of 22 pounds more than those who did not, while women who used the medication weighed an average of 10 pounds more than their non-medicated counterparts. And for more health news sent right to your inbox, sign up for our daily newsletter. 2 These brands have the greatest impact on your weight.
The Yale study specifically looked at two types of antihistamines which, at the time of the study, were only available by prescription: Zyrtec and Allegra. Today, these brands are available as OTC allergy treatments alongside Benadryl—and the Obesity Medicine Association reports that because they “have the same strength as the prescription versions,” they most likely trigger the same side effects. And for more on essential medical news, If You Take This Medication, U.S. Officials Have a New Warning for You. 3 They increase appetite and decrease energy.
“From clinical experience and solid scientific research demonstrating how histamine affects our appetites, it is safe to say that antihistamines probably do affect weight gain,” writes Vivek Gupta, MD, MPH, a weight loss specialist, via the Obesity Medicine Association site. He explains that histamines decrease hunger by “affecting the appetite control center in our brains.” Antihistamines, on the other hand, interfere with the signals that tell us when we’re full, resulting in overeating.ae0fcc31ae342fd3a1346ebb1f342fcb Gupta also notes that antihistamine medications can make users feel sluggish, leading to a reduction in the number of calories they burn over the course of the day. “While first generation antihistamines like Benadryl are more prone to make you sleepy, even second-generation medications like Zyrtec, when broken down by the body, result in byproducts that have a mild sedative effect,” Gupta explains. 4 One brand may have a less pronounced effect on your weight.
If you’ve experienced unexpected weight gain and you take any of these types of antihistamines, Gupta suggests switching to a different formulation. “If you need an antihistamine for frequent allergy symptoms…the best choice is Claritin because it does not cross into the brain and has less effect on appetite and sedation,” he says. “Otherwise, steroid nasal sprays, decongestants, and just reducing exposures to allergens are other options,” the weight loss specialist concludes. And for more on the side effects of your OTC routine, If You Can’t Sleep, This OTC Medication Could Be Why, Experts Say.