Weight-loss and type 2 diabetes medications such as Ozempic and Mounjaro have gained massive popularity worldwide, with many people turning to them for rapid weight reduction.
However, despite following medical advice, not everyone sees the same results — leaving many users frustrated about why these so-called “miracle” injections work well for some but not others.
A new study now suggests that genetics may be the hidden factor influencing how well these medications work.
Genes May Explain Differences in Weight Loss
According to research published in the prestigious journal Nature, scientists analysed DNA from nearly 28,000 patients taking semaglutide (found in Ozempic and Wegovy) or tirzepatide (found in Mounjaro and Zepbound).
The large-scale study discovered specific gene variants linked to better weight loss results and increased risk of side effects such as nausea.
Researchers found that genetics plays a significant role in treatment success, potentially paving the way for personalised obesity care tailored to individual DNA profiles.
How GLP-1 Drugs Like Ozempic Work
Medications such as Ozempic and Wegovy contain semaglutide, which mimics the GLP-1 hormone — a natural hormone released by the gut after eating.
This hormone:
- Signals fullness to the brain
- Slows digestion
- Reduces appetite
- Helps regulate blood sugar
On average, users of these medications lose around 10% of their body weight, though results vary widely.
Some individuals may lose over 25%, while others experience minimal weight reduction — sometimes less than 5% — even with consistent use.
Side effects such as nausea and vomiting can also lead some users to discontinue treatment early, resulting in regained weight.
Inside the Groundbreaking Study
Researchers from 23andMe analysed self-reported data from 27,885 individuals using GLP-1 medications over an eight-month period.
Using a genome-wide association study (GWAS), they identified key genetic variants linked to weight loss outcomes and side effects.
Key Genetic Findings:
- A variant in the GLP1R gene (rs10305420) was linked to greater weight loss
- People carrying this variant lost about 0.76 kg (1.6 lbs) more per allele
- Another variant (rs1800437) related to GIPR pathways increased the risk of nausea, especially among tirzepatide users
- These genes influence how strongly the drug interacts with receptors in the body
Because GLP-1 drugs target specific receptors, even small genetic differences can significantly alter how the body responds to treatment.
Why Genetics Matters in Weight Loss
Experts explain that DNA influences multiple aspects of metabolism, including:
- Hunger signals
- Fat storage
- Hormonal responses
- Drug tolerance
Individuals carrying what researchers call “super-responder” GLP1R variants may experience stronger appetite suppression because the drug binds more effectively to receptors.
On the other hand, people without these variants may experience:
- Reduced appetite control
- Slower weight loss
- Greater difficulty maintaining results
Similarly, genes linked to side effects may explain why some people experience severe nausea when using drugs like Mounjaro.
While genetics accounts for an estimated 5–10% of treatment variation, lifestyle factors such as diet, exercise, and environment remain critical.
What This Means for Patients
For individuals struggling to lose weight on medications like Ozempic or Mounjaro, genetic testing could provide valuable answers.
Doctors may eventually use DNA testing to:
- Predict how well a drug will work
- Identify risk of side effects
- Adjust dosage levels
- Recommend alternative treatments
- Tailor lifestyle strategies
This approach represents a shift from traditional trial-and-error treatments toward precision medicine, where therapies are customised based on genetic profiles.
The Future of Personalised Weight Loss Treatments
Researchers believe larger studies are needed to confirm these findings and integrate genetic screening into routine medical care.
Future developments could combine:
- Genetic testing
- Artificial intelligence
- Medical data analysis
This combination could help predict weight-loss success before treatment begins, potentially saving time, money, and frustration for patients.
Impact on India’s Growing Obesity Challenge
The findings may hold particular relevance for Obesity and Type 2 Diabetes management in India.
With more than 135 million adults affected by obesity, the introduction of affordable genetic testing — combined with modern medications — could significantly transform healthcare outcomes.
However, experts caution that accessibility and cost remain major challenges in implementing such personalised treatments at scale.
Important Medical Note
While medications like Ozempic and Mounjaro can support weight loss, they are not universal solutions.
Lifestyle habits — including balanced nutrition, regular physical activity, and consistent medical supervision — remain essential for long-term success.
Disclaimer: This content provides general information only and is not a substitute for professional medical advice. Always consult a qualified healthcare provider regarding medical decisions.