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Peptides For Weight Loss: How Do They Work?
Peptides For Weight Loss: How Do They Work?
MedExpress
Dr Sophie Dix
28 March 2024 | Updated: 6 February 2026
6 February 2026


Peptides are essential molecules that help your body function, but they’re also a key ingredient in weight loss treatments. Before you start a weight loss treatment, let’s take a look at what peptides are, how they work and what you need to consider when taking them.
What are peptides?
Peptides are small chains of amino acids, which make up proteins in your body. They’re essential for growth and signalling between cells. Some peptides, including GIP and GLP-1 receptor agonists like semaglutide and tirzepatide, may help with weight management by helping you use fat for energy and reducing your appetite.
How do peptides help with weight loss?
Peptides such as GIP and GLP-1 affect your blood sugar levels, which slows your digestion and reduces your appetite. This helps you use any glucose in your body for energy, and stops you storing it as fat.
GLP-1 receptor agonists like semaglutide and liraglutide are peptides that effectively reduce your body weight. They mimic the GLP-1 hormone in your body, regulating blood sugar and suppressing appetite.
Top peptides for weight loss
GLP-1 receptor agonists are some of the most effective peptides for weight loss. They work by mimicking hormones in your gut, controlling your blood sugar and making you feel full, faster. Semaglutide and tirzepatide can help you lose up to 15–20% of your body weight on average.
Considerations and safety
Before starting a weight loss treatment, it’s important to have a clinical consultation so you can get the right treatment for you. You need a prescription for a peptide treatment, and you need to check in with a clinician regularly to monitor your progress.
GIP and GLP-1s can cause side effects like nausea, constipation, and diarrhoea, but they usually reduce after you adjust to each dose. If you experience them, our clinical team is on hand to support you.
Interested in starting a peptide weight loss medication?
Find out what treatment is suitable for you on our website.
Next scheduled review date: 6 February 2029

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Authors

Written by: MedExpress
MedExpress

Medically reviewed by: Dr Sophie Dix
Dr. Sophie Dix is a behavioural neuroscientist dedicated to translating cutting-edge science into scalable, patient-centred healthcare. She is Head of Medical Affairs at MedExpress, leading evidence and content strategy to ensure products are grounded in robust science. Previously, she spent 15 years in drug discovery at Eli Lilly and later held senior roles in mental health research and digital health, including Director of Research at MQ and VP of Content at Koa Health.
Note from the experts
Remember: This blog shouldn’t be regarded as medical advice, diagnosis, or treatment. We make sure everything we publish is fact checked by clinical experts and regularly reviewed, but it may not always reflect the most recent health guidelines. Always speak to your doctor about any health concerns you have.