What Is Wegovy Made From, and How Does It Work in the Body?

Step 1: starting with a human hormone your gut already makes

To understand what Wegovy is made from, the most useful starting point is the hormone it copies. Your small intestine releases GLP-1 naturally in the minutes after you eat. It signals to the brain that food has arrived, prompts the pancreas to release insulin, and slows gastric emptying so nutrients are absorbed gradually. The problem is that natural GLP-1 breaks down in the bloodstream within about two minutes — far too short to be a medicine.

Novo Nordisk's scientists took the 30-amino-acid structure of human GLP-1 and made two targeted modifications. First, they swapped one amino acid (at position 34, arginine replaces lysine) to prevent a particular enzyme from degrading the molecule quickly. Second, they attached a long fatty-acid chain via a linker molecule. That chain lets semaglutide bind loosely to albumin, the most abundant protein in your blood, which effectively shields it from breakdown and keeps it circulating for days rather than seconds. The result is a molecule that acts like GLP-1 but stays active for a full week. You can read more about the wider semaglutide molecule on our semaglutide overview page.

If you are curious about what semaglutide is made from, it shares roughly 94% of its amino-acid sequence with human GLP-1 and is sometimes described as a GLP-1 receptor agonist because it activates the same receptor that the natural hormone does, just for much longer. The NHS medicines page for semaglutide gives a plain-English overview of how it works and what to expect.

Step 2: formulating it into a medicine people can actually use

Synthesising the semaglutide molecule is only part of the process. Turning it into a usable medicine requires a formulation that protects the active ingredient and delivers it reliably to the body.

For the Wegovy injection, semaglutide is dissolved in a clear aqueous solution alongside a buffer to keep the pH stable, a preservative, and a small amount of a tonicity agent. That solution is loaded into Novo Nordisk's pre-filled pen device, which keeps the liquid refrigerated until you use it. The pen itself is not just packaging; it meters the dose precisely so the right amount is delivered each time. Each pen contains four weekly doses at the same strength, with no measurement required from the patient.

The Wegovy tablet, approved by the MHRA on 11 June 2026 as the first oral GLP-1 medicine licensed in the UK for weight management, takes a different approach. Semaglutide on its own is a large peptide molecule that the stomach would digest before it could be absorbed. To get around this, the tablet co-formulates semaglutide with an absorption enhancer called SNAC (sodium N-[8-(2-hydroxybenzoyl) aminocaprylate]). SNAC temporarily changes the local environment in the stomach, allowing the semaglutide to cross the stomach lining and enter the bloodstream. This is why the tablet must be taken first thing in the morning with only a small amount of plain water, at least 30 minutes before food, drink or other medicines — to give that chemistry the best possible conditions. No refrigeration is needed, which makes it considerably more travel-friendly. Our Wegovy treatment page covers both pen and tablet formats in more detail.

Step 3: how the finished medicine acts once it is in your body

Once semaglutide is circulating, it binds to GLP-1 receptors in several places at once. In the hypothalamus, the part of the brain that regulates appetite, it reduces hunger signals. In the stomach it slows the rate at which food moves into the small intestine, so you feel full for longer after eating. In the pancreas it supports insulin release in proportion to blood glucose, which is why it does not cause the kind of low blood sugar associated with some older diabetes medicines when used in people without type 2 diabetes.

The licensed maintenance doses for Wegovy injection progress from 0.25mg up to 2.4mg weekly, with the higher 7.2mg dose approved by the MHRA in 2026 for eligible adults with obesity. The tablet follows a separate schedule from 1.5mg up to a 25mg maintenance dose. In the STEP 1 trial, adults using the 2.4mg injection lost an average of around 15% of their body weight over 68 weeks alongside lifestyle changes, as published in the New England Journal of Medicine. These are clinical trial averages, individual results depend on a range of factors a prescriber will discuss with you.

It is worth knowing that Ozempic also contains semaglutide but is licensed for type 2 diabetes rather than weight management, and Rybelsus is the oral semaglutide tablet licensed for diabetes. Neither is interchangeable with Wegovy for weight loss purposes. Our page on how Wegovy is manufactured goes further into the production process if you want the detail behind the formulation steps described here. For those curious about the broader chemistry behind the active ingredient, the page on what semaglutide is made out of covers the molecular structure in more depth.

What this means for you if you are considering treatment

Understanding what Wegovy is made from is genuinely useful, not just scientific trivia. Knowing that semaglutide mimics a hormone your body already produces helps explain both the mechanism and the most common side effects, nausea, changes in appetite, and occasional digestive disruption are largely the extended version of what natural GLP-1 does in larger amounts. Those effects are typically most noticeable in the first days after a dose increase and tend to settle as the body adjusts.

It also explains why the tablet must be taken with such a specific routine. That 30-minute window before your first coffee of the morning is not arbitrary; it is the chemistry of SNAC doing its job without interference. A question our prescribers hear regularly is whether the pen or tablet is the better option, and understanding who makes Wegovy and how that manufacturer shapes the product can help put that choice in context, though the honest answer remains that it depends on individual lifestyle, tolerance and clinical history, which is exactly the kind of thing a consultation is for.

If you are looking at the cost of private treatment, our weight-loss treatment overview sets out what is included in a private prescription service like ours. Wegovy is a prescription-only medicine, and suitability is assessed individually. If you would like to find out whether it could be appropriate for you, speak to our prescribers through a free consultation, reviewed the same day by a GPhC-registered Independent Prescriber, never automated software.