GLP-1 medications for weight loss like Mounjaro and Wegovy have become incredibly popular, and for some people they really do feel life-changing. But why do some people respond differently? It’s rarely about “willpower” — it’s usually about biology.
How do GLP-1 medications for weight loss work?
GLP-1 drugs work by mimicking a gut hormone that slows digestion, helps you feel fuller, and steadies blood sugar by stimulating the release of more insulin. That sounds simple, but how well those signals are received depends on what your metabolism is already dealing with.
Individual responses: will GLP-1 medications work for me?
Some people may have underlying insulin resistance, higher appetite hormones, or a tendency to experience big blood sugar swings. For them, GLP-1 medications for weight loss can feel like someone has finally turned the volume down on hunger. Others already have fairly stable glucose control, or their appetite is driven more by stress, sleep issues, or habit — in those cases, the effect might feel more subtle.
Genetics
Genetics plays a bigger role than people realise. Variants in genes such as FTO, MC4R, TFC7L2, or those involved in dopamine signalling can influence appetite, reward-driven eating, how quickly you feel full, and even how strongly you respond to insulin. GLP-1 can help “buffer” some of that, but it won’t completely override your genetic wiring. This is why some people still need a high-protein, fibre-rich diet to feel properly satisfied, even whilst taking GLP-1 medication.
Recent research
In fact, recent research suggests that individual responses based on genetics play a significant role not just for weight loss predisposition, but specifically for responses to GLP-1 medications for weight loss.
Hormones
Hormones also matter. If your thyroid is slightly underactive, or testosterone/estrogen levels aren’t optimal, your metabolic rate is already in a slower gear. GLP-1’s can support weight loss, but they won’t automatically correct hormonal imbalance — which is why personalised nutrition, sleep, stress management, and the right training approach still make such a difference.
Key Takeaway
The medication is just one piece of the puzzle. If your genetics, metabolism, or digestion need extra support, those factors don’t disappear just because you’ve added a weekly injection. This is also why weight can return when people stop the medication — the underlying drivers are still there, waiting to be addressed.
My work with nutrigenomics is about understanding those drivers. Once you know how your body is programmed to regulate appetite, burn energy, handle carbohydrates, or respond to exercise, it becomes much easier to put the right lifestyle and nutrition strategies in place — whether you’re using GLP-1 medications for weight loss or not.
If you’re curious about how your genetics might shape your response to these medications, or how to build a sustainable plan around them, I’m always happy to guide you through what will work best for your biology at The DNA Nutritionist.
