Scientists have identified genetic variations that explain why weight loss rates and the intensity of side effects vary when taking anti-obesity medications.
The study, published in the journal Nature, is based on data from approximately 28,000 customers of the DNA-testing service 23andMe, who shared their personal experiences using GLP-1 receptor agonists (such as semaglutide and tirzepatide).
The research revealed that a specific variation in the GLP-1 receptor gene is directly linked to the drug’s efficacy. Patients carrying one copy of this genetic variation lost an average of 0.76 kg more over 8 months than those without it, while those with two copies saw a difference of 1.5 kg. Although the impact of genetics on the rate of weight loss is relatively small, scientists believe it helps us better understand the underlying biological mechanisms.
The influence of genetic factors on the risk of side effects is far more significant. The study showed that certain genetic variants increase the probability of vomiting by 57% and nausea by 36%. An especially high rate was observed with tirzepatide, where a specific change in the GIP receptor increases the risk of vomiting by 83%.
According to the researchers, the fact that these genetic variations were found in the very receptors that the medications target confirms the biological validity of the discovery.
While it is still too early to use this data widely in clinical practice, the study provides an important foundation for personalized medicine, enabling doctors to predict in advance which specific drug will be the safest and most effective for a given patient.
