Your Friend Lost More on the Same Medicine. Why?

Her result is not a measure of your effort.

Your friend’s weight is falling faster. She seems to have fewer side effects. You are taking the same medicine, so you start wondering what you are doing wrong.

That comparison leaves out too much. People can respond differently to weight-loss medicines. Your progress deserves its own review, based on your treatment and health—not someone else’s numbers.

What did the new research find?

A study published in Nature on April 8, 2026, examined 27,885 people who reported using medicines including semaglutide and tirzepatide. The researchers looked for links between genetic differences, weight loss, and side effects.

One small difference in DNA was linked with about 1.7 extra pounds lost per copy inherited. People can inherit a copy from each parent. Other genetic findings were linked to nausea or vomiting. The weight difference was modest; it does not explain every gap between two people’s results.

The name on the prescription is only part of the story.

The study also found that the medicine used, dose, time on treatment, and health factors such as diabetes helped explain different results.

Before you compare pounds lost, put your own details on paper: when you started, your current dose, changes in dose, missed doses, and how you have been feeling. A prescriber can use that information to judge whether the plan is helping and whether it needs adjusting.

A slower response is something to discuss. It is not a reason to increase the dose yourself or keep side effects to yourself.

Does this mean I need a DNA test?

This study does not show that choosing a drug or dose through DNA testing improves treatment. It is a research finding, not a proven way to choose your prescription.

You can have a useful medication review now. Bring your progress, side effects, current medicines, and health history. Your clinician can discuss the next step without treating this one gene finding as the answer.

Look at what is changing besides your weight.

Weight loss can improve blood pressure, blood sugar, and some other health problems. Those changes belong in your follow-up conversation too.

Tell your care team how everyday life feels. Can you eat and drink comfortably? Are stairs easier? Can you keep doing your usual strength exercises? These observations add context; they do not diagnose the cause of a symptom.

If side effects interfere with eating, drinking, or daily activities, contact your prescriber. You do not have to wait until your next weigh-in to ask for help.

Your next step is a review of your own plan. Ask what progress is reasonable for you, how you will measure it, and when you will check again.