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Dr. Chris Thompson

Part IV · Reengineering metabolism

How GLP-1 medications work

GLP-1 is one of the body's own satiety signals. The medications copy that signal, amplified and made to last, and appetite drops considerably as a result.

The short answer

GLP-1 medications are engineered copies of a satiety hormone the gut already makes, designed to be stronger and to last longer. Appetite falls substantially for as long as the medication continues. When it stops, most of the weight that was lost returns.

The effect persists for as long as the treatment does.

A signal the body already makes

GLP-1 is a hormone that your gut releases when you eat. It signals to the brain that you are satisfied, slows the rate at which the stomach empties so that fullness lasts longer, and helps regulate blood sugar.C-II-05

The medications are copies of that signal, engineered to be stronger and to last far longer than the body's own version. Appetite drops, often considerably, and for many people eating less becomes possible in a way it had not been before.C-IV-07

This is a meaningful advance. For the first time, there is a way to turn hunger down from the inside rather than asking people to resist it.C-IV-07

Importantly, there is a trade-off, and it is not unique to medication. Substantial weight loss by any route takes some lean tissue with it, and the loss of muscle and physical function is a recognized concern with rapid, large reductions.C-IV-08

What happens when you stop

What happens after treatment stops is the part of the evidence that matters most, and it is where optimism is least justified.

68 weeks

Reached about 17% below starting weight at week 68, then stopped

⅔

Of the loss regained once treatment stopped C-III-09

This regain is not a failure of the medication or of the person; it is what follows when a treatment works by sustaining a signal, because the effect is present while the treatment is.

References

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  10. Neeland IJ, et al. Changes in lean body mass with glucagon-like peptide-1-based therapies and mitigation strategies. Diabetes Obes Metab. 2024. PMID 38937282
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