How do Ozempic, Wegovy, Mounjaro and Zepbound work?
Four famous brand names, two molecules, and one trick: give a two-minute hormone a week-long lifespan.
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Ozempic and Wegovy contain semaglutide, and Mounjaro and Zepbound contain tirzepatide. Both are look-alikes of hormones your gut releases after a meal. Semaglutide is a modified version of GLP-1, and tirzepatide imitates GLP-1 and a partner hormone called . Switching on those receptors slows the stomach, prompts the pancreas to release insulin and sends signals to the brain that affect appetite. All four are prescription medicines: the FDA says patients should obtain a prescription from their doctor and fill it at a state-licensed pharmacy. This lesson explains how they work, not whether anyone should use them.
The engineering puzzle was lifespan. Natural GLP-1 has a half-life of only about two minutes because an enzyme called DPP-4 rapidly breaks it down. At Novo, a team led by Lotte Bjerre Knudsen developed liraglutide in 1998, and a team including Jesper Lau, Thomas Kruse and Paw Bloch went on to develop semaglutide. Their trick has two parts. Swapping one , an alanine, stops DPP-4 breaking the molecule down, and a long carbon chain makes it cling to , a protein in the blood, so it stays in circulation. The result is a half-life of about seven days, which is why many of these drugs are injected only weekly.
Tirzepatide adds a second target. It has a greater affinity for receptors than for GLP-1 receptors, and that dual action has produced greater reductions of high blood sugar than a drug that hits GLP-1 alone. A fatty diacid chain gives it the same -clinging trick.
Semaglutide (Novo)
- Modified version of GLP-1
- Brands: Ozempic, Rybelsus, Wegovy
- Half-life about seven days
Tirzepatide
- analog and GLP-1
- Brands: Mounjaro, Zepbound
- Fatty diacid chain binds , so doses can be spaced out
Honestly, scientists do not have the whole picture yet. One source notes it is unknown whether these drugs act only by reducing the energy people take in or also by increasing the energy the body burns.
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Recap
These are prescription medicines that copy gut hormones and are built to last, with a swapped amino acid and a long attached chain.
💡 A trick to remember it · Give the two-minute hormone a swapped letter and a long tail to cling to the blood, and it lasts a week.
Surprising fact · One source notes it is still unknown whether these drugs work only by cutting energy intake or also by raising energy burned.
Sources (5)
No source, no claim. Every fact in this lesson (16 claims) cites at least one of these.