Few medicines have attracted as much attention in recent years as GLP-1 drugs. Names such as Ozempic, Wegovy and Mounjaro have moved well beyond doctors' offices and into everyday conversation.

Behind the headlines is a fascinating scientific story.

It starts with something our bodies already make

Whenever we eat, our digestive system does much more than simply break food down.

Cells in the intestine release a hormone called GLP-1, or glucagon-like peptide-1, which helps the body respond to incoming food.

GLP-1 signals the pancreas to release insulin when blood glucose is elevated. It also reduces glucagon, a hormone that influences digestion, appetite and feelings of fullness.

It is part of the body's communication system telling us:

Food has arrived. Slow down the ingestion process and signal when enough has been eaten.

This made GLP-1 an intriguing target for researchers looking for better ways to treat type 2 diabetes.

There was, however, one rather large problem.

Natural GLP-1 disappears incredibly quickly.

An enzyme called DPP-4 rapidly breaks it down, making an active GLP-1 disappear in one to two minutes.

Scientists needed to find a way to make its effects last.

An unlikely clue from a venomous lizard

Part of the answer came from an unexpected place: the Gila monster.

Endocrinologist Dr. John Eng studied Gila monster venom in the early 1990s at the Bronx VA Medical Center.

Dr John Eng noticed this animal rarely feeds, probably a few times a year, and thought there might be something present in its saliva that prevented the animal from feeling hungry. He studied its saliva and found a hormone peptide called exendin-4.

Exendin-4 behaved remarkably like human hormone GLP-1. It could activate the same GLP-1 hormone receptor and produce similar biological effects of the feeling of fullness.

There was one particularly useful difference.

It lasted longer.

Unlike natural human GLP-1, exendin-4 was considerably more resistant to being broken down by DPP-4.

Researchers realised they had found something potentially valuable.

A synthetic version of exendin-4 was eventually developed into exenatide, approved in the United States in 2005 for the treatment of type 2 diabetes.

But the story didn't stop there.

How do you turn 2 injections a day into one every seven days?

The next challenge was convenience.

Early GLP-1 medicines could require frequent injections. Scientists therefore continued experimenting with ways of keeping GLP-1 hormone receptor activation working for longer.

One solution involved albumin, a protein naturally abundant in our blood.

A new peptide, Semaglutide — the active ingredient used in Ozempic and Wegovy — was engineered so that it mimics our natural gut hormone GLP-1 and also binds strongly to albumin. This allows the molecule to circulate in our system for much longer.

Its half-life is approximately one week.

Other ways to deliver GLP-1 medicines

The once-weekly injection is not the only possible way to deliver a GLP-1 medicine.

Some GLP-1 medicine are available as tablets. Oral semaglutide, for example, uses a specialised formulation designed to help a fragile peptide survive the digestive tract and be absorbed into the bloodstream. This is technically challenging because proteins and peptides are normally broken down during digestion, and only a small amount may be absorbed.

Oral treatment can therefore offer an alternative to injections, but it still has specific instructions for taking it and may not be suitable for everyone.

Patches are a particularly interesting example.

Ordinary adhesive patches sold online as “GLP-1 patches” often contain vitamins, plant extracts or other supplements rather than semaglutide, tirzepatide or another proven GLP-1 receptor agonist.

There is currently no widely approved GLP-1 weight-loss patch that has been shown to reproduce the effects of injectable medicines. The skin is an effective barrier, and large peptide molecules do not simply pass through it in therapeutically useful amounts.

If someone feels that an online patch is helping, part of that perceived benefit could arise from expectation or a placebo effect rather than from a proven pharmacological action. In that situation, a $99 patch would not necessarily be any more effective than a $35 patch.

When eating less creates another challenge

One of the most common difficulties with GLP-1 medicines involves the digestive system.

Nausea, vomiting, diarrhoea, constipation and abdominal discomfort can occur, particularly when treatment begins or the dose increases.

Reduced appetite creates another, less obvious challenge.

Eating less may be the desired effect when weight reduction is the goal, but the human body still needs sufficient protein, vitamins, minerals and energy. Supplements may be useful when food intake is insufficient. Depending on individual needs, it may be recommended to take a suitable multivitamin or specific supplements alongside with GLP-1 medicines.

A remarkable medicine — but not a magic one

The rise of GLP-1 medicines represents much more than the latest weight-loss trend.

The potential benefits are significant. But anyone considering GLP-1 injections solely to lose weight should pause before treating them as a quick or cosmetic solution.

These are prescription medicines with real effects on appetite, digestion, blood sugar and other body systems. They may be appropriate for some people with obesity or overweight-related health risks, but a lower number on the scales does not automatically mean better health.

Digestive side effects, nutritional adequacy, preservation of muscle, long-term treatment and the possibility of weight regain after stopping all form part of the picture.

Medical disclaimer: This article is for general information only and is not intended as medical advice. GLP-1 medicines have different indications, contraindications, warnings and side-effect profiles. Treatment decisions should be discussed with an appropriately qualified healthcare professional.