Semaglutide is the active ingredient in two medicines you may have heard of: Ozempic and Wegovy. Since 2022, doctors have been able to prescribe it to help with weight management. When combined with healthier eating and more physical activity, it can help many people lose weight and keep it off.

How Semaglutide Works

Semaglutide works on a natural hormone receptor in the brain called GLP-1. This receptor plays a role in controlling appetite and how many calories you eat. By activating it, semaglutide helps you feel fuller sooner, reduces hunger, and lessens cravings for certain foods.

In one study by the medicine’s manufacturer (Novo Nordisk), people who took semaglutide for 4 months ate about 35% fewer calories at a buffet meal compared to people who didn’t take it. This was because they felt more satisfied, had fewer cravings (especially for savoury or dairy foods), and had less desire for sweet and fatty foods.

Weight Loss Results

On average, patients in studies lost 15% of their body weight. For example, someone starting at 105 kg (around 16.5 stone) might lose about 15–16 kg (over 2 stone).

• 2 out of 3 people lost more than 10% of their body weight.

• Semaglutide also reduced waist size, improved blood pressure, lowered cholesterol, and decreased inflammation in the body.

Benefits Beyond Weight Loss

Losing weight with semaglutide can bring a wide range of health improvements, including:

• Better mobility and less joint strain (for example, less knee pain from osteoarthritis).

• Improved blood sugar control, as semaglutide helps the body release insulin when blood sugar is high, while also reducing a hormone called glucagon (which normally raises blood sugar).

• Improvements in other conditions linked to weight, such as sleep apnoea, asthma, fatty liver disease (NAFLD), and polycystic ovary syndrome (PCOS).

• Better heart and circulation health: In July 2024, Wegovy was approved in the UK to lower the risk of heart attack and stroke in people living with obesity or excess weight (BMI 27 or above) who already have heart or circulation problems.

In a major study of over 17,000 people who had already experienced heart disease (like a heart attack or stroke), semaglutide reduced:

• Risk of death by 19%

• Risk of another heart attack by 28% within 4 years

Possible Side Effects

Like all medicines, semaglutide can cause side effects. Most are mild to moderate, and many improve with time. The most common include:

• Nausea, vomiting, diarrhoea, constipation, or stomach pain

• Headaches, dizziness, heartburn, or bloating

• Hair loss (less common)

About 1 in 8 people stopped taking semaglutide in studies because of side effects. Rare but more serious risks include gallstones and inflammation of the pancreas (pancreatitis).

Emerging Research

Scientists are discovering more about semaglutide beyond weight and blood sugar control:

• It may reduce inflammation, which is important because inflammation is linked to heart disease, kidney problems, and liver issues.

• Early studies suggest semaglutide may protect kidney function in people with diabetes.

• New research in the US has also found that GLP-1 medicines like semaglutide might lower the risk of obesity-related cancers. Patients on GLP-1 treatments had fewer cases of bowel cancers (16% fewer colon cancers and 28% fewer rectal cancers) compared to people on other diabetes medicines.

Key Takeaway

Semaglutide (Ozempic/Wegovy) is more than just a weight-loss medicine. It can improve overall health, reduce risks linked to obesity, and may even provide protection against serious diseases in the long term. However, it isn’t suitable for everyone and can cause side effects, so it should always be prescribed and monitored by a healthcare professional.