Beyond Weight Loss: Biomarker Improvements from GLP-1 Medication
When Wegovy launched in the UK in September 2023, it marked a turning point in how we approach medicated weight loss. While primarily a blood testing company, Thriva saw an opportunity to provide meaningful health benefits to our customers. In December 2023, we launched our own Wegovy offering, including baseline and follow-up blood tests for those on the programme. This quickly evolved to include the newly developed Mounjaro in February 2024. A renewed focus on our core product meant closing the programme to any new applicants, at which point more than 250 customers had been approved for the medication.
Both Wegovy (semaglutide) and Mounjaro (tirzepatide) are known as GLP-1 agonists. These medications mimic the effects of naturally occurring hormones that control blood sugar and regulate appetite. Studies have shown that overweight or obese individuals taking GLP-1 agonists can see a steady and long term weight loss.
However, potentially of greater value to the customer is the health improvements that are happening internally. With regular blood testing of cholesterol, inflammation and diabetes markers, we were able to see how those on the weight loss programme were improving over time.
Here are the results seen by Thriva customers on our medicated weight loss programme.
Reduction in body weight
Customers enrolled in Thriva’s weight loss programme were asked to complete regular questionnaires, which included reporting their most recent weight. Below is a plot of each survey response, adjusted to show a percentage change in weight relative to their initial starting point.
As you can see, there are a wide range of responses, likely reflecting a combination of genetics and adherence to any changes to exercise or eating habits. On average, customers lost 7.0% of their weight in the first 13 weeks and 15.5% in the first year, similar to the values shown in the original research.
Improved heart health
If you are overweight or obese, you have an increased chance of having high levels of harmful cholesterol particles, elevating your risk of heart disease. One of the most common biomarkers to assess your risk is LDL cholesterol. Higher levels are associated with an increased risk of atherosclerosis, the main driver of heart disease or stroke. Having high triglycerides can also drive up your other markers.
There is an even stronger relationship between heart health and advanced markers known as apolipoproteins. Though LDL cholesterol and Apolipoprotein B are often correlated, the latter is a stronger predictor of cardiovascular risk.
Customers on the programme for at least three months were given a second blood test to monitor changes from baseline. Isolating the customers whose baseline results were classified as abnormal, this table illustrates the improvements seen across key biomarkers of cardiovascular health.
An important takeaway here is how, in many cases, Thriva customers were well on track to bring their results below the threshold for an abnormally high result. In fact, as of the second test, 28–44% of abnormal lipid biomarkers dropped to normal or optimal ranges.
Reduced inflammation
Body fat, particularly visceral fat, is a major driver of systemic inflammation in the body. Visceral fat is the deeper fat tissue that surrounds your organs, and it’s a major source of inflammation. CRP is a commonly measured marker of inflammation, and the liver releases more CRP in response to visceral fat. Hs-CRP is a more sensitive test that can detect lower levels of inflammation.
We are able to see the relationship between excess body fat, based on BMI, and hs-CRP levels across all of Thriva’s customer data. Average hs-CRP moves from an optimal range (< 1 mg/L) for those borderline overweight, up into the high range (> 3 mg/L) for Class II obesity and beyond.
Regular testing of hs-CRP allows us to see how GLP-1 medications can drive less-visible but clinically meaningful outcomes. Rather than relying solely on the median result, we analysed the data by separating customers based on their baseline levels. This allows us to track improvements based on each customer’s initial starting point.
We can see that the biggest reductions come from those with an initially high hs-CRP, lowering it by 30% in the first 3 months. The customers who tested again at six months saw average reductions of 38.7% among those in the normal range at baseline (2.19 to 1.34 mg/L), and 44.4% when starting with a high baseline level (5.44 to 3.03 mg/L). These outcomes closely mirror findings from clinical studies on hs-CRP reduction with GLP-1 medications.
Lower risk of diabetes
Over 3 million UK adults have Type 2 diabetes, and over 13 million are at increased risk of developing it, a state often referred to as "pre-diabetes" (non-diabetic hyperglycaemia). Excess body weight is a major risk factor for Type 2 diabetes due to its contribution to insulin resistance; indeed, over 90% of individuals with Type 2 diabetes are overweight or obese.
GLP-1 receptor agonists help reduce the risk of developing Type 2 diabetes in two ways: they promote weight loss and enhance insulin secretion, improving glycaemic control. This is also why they are used as a treatment option in those with established diabetes.
HbA1c is a key biomarker used in the diagnosis and monitoring of diabetes. It reflects average blood glucose levels over the preceding 2 to 3 months. An HbA1c of 48 mmol/mol or higher can be diagnostic of diabetes if persistently raised or associated with symptoms. Values between 42–47 mmol/mol are consistent with pre-diabetes, which carries an increased risk of progression to Type 2 diabetes.
The accompanying graph illustrates individual changes in HbA1c over a 3-month period among individuals who initially had elevated levels. Approximately 90% (49 of 56) showed a reduction in HbA1c, and over 60% achieved values within the recommended range for non-diabetic individuals.
Another biomarker that has been shown to indicate insulin resistance is Triglyceride to HDL ratio (TG/HDL ratio). Higher triglycerides are a risk factor for insulin resistance, while higher HDL is considered a protective factor. The ratio between the two was found to link more closely to insulin resistance than either on their own.
Customers with a high baseline (> 1.75) saw a 10.6% reduction after 3 months and a 36% reduction after 6 months on the medication, bringing their average TG/HDL ratio down from 2.90 to 1.86.
Conclusion
This demonstrates how regular blood testing allows customers to see the health improvements that come from GLP-1 medications beyond scale weight. While weight loss remains the main goal for many, improvements in these key biomarkers are just as important when it comes to long-term health.
Many of these changes are likely linked to the weight loss itself, particularly the reduction in harmful visceral fat, which plays a key role in driving inflammation and metabolic dysfunction. There may also be additional benefits that come from the changes customers have made to their total calorie intake and food selection.
For anyone losing weight, with or without the help of medication, tracking biomarkers over time can provide a more complete picture of progress to optimal health, highlighting improvements that include lower harmful cholesterol particles, reduced inflammation and improved blood sugar control.