I initially wrote about the use of GLP-1 analogues in my blog Keeping Your Weight Stable in September 2022.

Since then, on an almost daily basis we read about Ozempic (semaglutide), which was licenced for diabetics, then Wegovy (also semaglutide), which was licenced for weight loss, and now Mounjaro (tirzepatide).

These drugs cause weight loss by increased insulin levels, appetite suppression, and burning fat. In addition to lifestyle improvements in sleep, diet and exercising, they will play a long-term role in the future of anti-ageing medicine.

So what is Semaglutide?

It is an analogue of GLP (glucagon like peptide)-1, which works at receptors in the pancreas, stomach, intestine and nervous system.

GLP-1 increases insulin. Insulin allows cells including muscle and liver to take up glucose and store it as glycogen. GLP-1 also inhibits the production of the antagonist hormone to insulin known as glucagon, which would otherwise cause glucose release into the bloodstream.

GLP-1 slows down gastric emptying, so you feel fuller for longer. This is probably the major source of the common side effects of nausea and constipation. GLP-1 also works centrally on the brain by telling the brain that we are full. This reduces hunger and appetite.

So, what is Tirzepatide?

This, in addition to working on GLP-1 receptors, works on GIP (glucose dependent insulinotropic polypeptide) receptors. These receptors are found in the pancreas, in fat cells and other areas of the nervous system.

Additional effects are due to the burning of fat known as lipolysis including in the central fat deposits like the liver.

It works at receptors for GLP-1 and GIP in the brain further enhancing appetite suppression.

It reduces cholesterol levels.

Side effects are much less common than Ozempic.

Ozempic/ Wegovy vs Mounjaro

Ozempic can results in weight loss of around 15% of your body weight in 12 months. Mounjaro can result in up to 25%. With increasing availability in the UK it is superior at reducing blood sugar levels and reducing weight.

Drugs, however, are far from the only solution for improving your lifespan:

• Sleep is very important in helping metabolic changes – a minimum of 6-8 hours is needed.

• A healthy diet avoiding sugar.

• Exercise involving the muscles like lifting weights as opposed to general cardiovascular exercise like running or cycling will best augment the weight loss associated with these hormonal mechanisms as there is increased deposit of glucose as glycogen in the muscles.