The short answer: if you want a low-cost safety check, Medichecks' GLP-1 Monitoring test (£99 plus draw) covers kidney, liver, blood count, lipids, HbA1c, ferritin, folate and lipase. If you want a full baseline that also covers thyroid, B12, ApoB, vitamin D and hormones, Lola Health's Peak Insights 70 or TrueVitals' Ultimate (the only one here with fasting insulin and cystatin C) cover more. Whichever you choose, it adds to your prescriber's monitoring; it doesn't replace it.
A UCL study published in BMC Medicine estimated that 2.9% of adults in England, Wales and Scotland, about 1.6 million people, used drugs such as Wegovy and Mounjaro for weight loss between early 2024 and early 2025. Women used them at about twice the rate of men (4% vs 1.7%), and a further 6.5% of non-users, about 3.3 million people, said they were interested in using them in the next year. The estimates come from a representative survey of 5,260 adults (Jackson et al., BMC Medicine, 2026; UCL news).
UCL's summary of the study notes that many people are getting these medicines outside the NHS. That is where a private blood test can help: a baseline before you start, and a check once the dose and your diet have settled.
These are the markers worth having at baseline and on repeat. They describe your health while on treatment; they are not a test of whether the medicine is "working", and none of them diagnoses a side effect on its own.
| Marker | Why it matters on Mounjaro or Wegovy |
|---|---|
| HbA1c | Your average blood sugar over the last two to three months (Diabetes UK). The clearest single number for metabolic change. HbA1c test |
| Fasting insulin | Shows how hard your body is working to keep glucose normal. Needs a fasted sample. |
| Lipids and ApoB | Cholesterol and triglycerides usually change with weight loss. ApoB counts the particles that carry cholesterol into artery walls. ApoB test |
| Liver function (ALT, GGT) | Fatty liver is common with excess weight; liver enzymes give a baseline to compare against. Liver test |
| Kidney function: creatinine, eGFR, cystatin C | Both product leaflets warn that nausea, vomiting and diarrhoea can cause dehydration, and the Mounjaro leaflet says this may lead to a decrease in kidney function (Mounjaro PIL; Wegovy PIL). Cystatin C is less affected by muscle mass, which changes as you lose weight. Kidney test |
| Ferritin, B12, folate | Eating much less can mean less iron, B12 and folate. Worth knowing if you feel unusually tired. Tired on Mounjaro? |
| Thyroid (TSH, free T4) | The NHS lists tiredness and weight gain among the symptoms of an underactive thyroid (NHS). Worth ruling out at baseline. |
| Full blood count | Anaemia and other blood count changes; a standard part of any baseline. |
| Lipase or amylase | The Mounjaro leaflet lists raised pancreatic enzymes as a common finding. A blood test does not rule pancreatitis in or out: severe, persistent stomach pain needs urgent medical help, not a test kit. |
From each provider's own product page on 15 October 2026. All use a venous sample.
| Panel | Price | HbA1c | Fasting insulin | Lipids | ApoB | Liver | Kidney (eGFR) | Cystatin C | B12 | Ferritin | Folate | Thyroid | FBC |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Medichecks GLP-1 Monitoring (34) | £99 + draw | Yes | No | Yes | No | Yes | Yes | No | No | Yes | Yes | No | Yes |
| Lola Health Core Health 45 | £125, +£35 draw | Yes | No | Yes | No | Yes | Yes | No | Active | Yes | No | No | Yes |
| Lola Health Peak Insights 70 | £200, £235 with draw | Yes | No | Yes | Yes | Yes | Yes | No | Active | Yes | Yes | Yes | Yes |
| Medichecks Ultimate Performance (56) | £199 + draw | Yes | No | Yes | No | Yes | Yes | No | Active | Yes | Yes | Yes | Yes |
| Forth Ultimate Health Check (52 listed) | £399 + draw | Yes | No | Yes | No | Yes | Yes | No | Active | Yes | Yes | Yes | Yes |
| TrueVitals Ultimate (140) | £349 + £19 / £39 draw | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Total | Yes | Yes | Yes | Yes |
Prices checked October 2026: Medichecks GLP-1 Monitoring (also includes lipase; venous at a partner clinic or by home nurse +£59; doctor review included; results in about 5 working days), Lola Core Health 45, Lola Peak Insights 70 (results reviewed by a GMC-registered doctor), Medichecks Ultimate Performance (offer price), Forth Ultimate. Thriva's GLP-1 page says its medicated weight loss programme, which included blood tests, has closed to new applicants. Check the provider before you buy.
TrueVitals facts: Ultimate: 140 biomarkers (139 for women), £349 + £19 clinic draw or £39 home visit, venous sample, Nationwide Pathology (UKAS-accredited), clinician-reviewed report within 4 working days, 103 partner clinics.
Where TrueVitals fits: if you want one baseline that covers everything in the table, including fasting insulin and cystatin C, which none of the other panels list, and a written report that reads the results together, so a repeat test three months later shows what changed. Weaknesses: it costs more than the focused tests, booking is by phone after payment, the Ultimate measures total rather than active B12, and it is a newer brand.
It can't tell you whether the dose is right, diagnose pancreatitis or gallstones, or replace your prescriber's checks. The Wegovy leaflet describes acute pancreatitis as "a serious, potentially life-threatening condition" and advises stopping the medicine and getting urgent help for severe, persistent pain in the stomach area (Wegovy PIL).
It depends on what you want. For a low-cost safety check of kidney, liver, blood count, lipids, HbA1c, ferritin, folate and lipase, Medichecks' Weight Loss Injection (GLP-1) Monitoring test is £99 plus the draw. For a broader baseline that adds thyroid, B12, ApoB, vitamin D and hormones, Lola Health's Peak Insights 70 (£200 to £235) or TrueVitals' Ultimate (£349 plus draw, 140 biomarkers, including fasting insulin and cystatin C) cover more. None replaces the monitoring your prescriber asks for.
A sensible baseline covers HbA1c, kidney function, liver function, a lipid profile, a full blood count, thyroid function, and iron, B12 and folate. It shows where you started, so later changes can be read against it. Your prescriber decides what is clinically required; tell them about any existing conditions and medicines.
Both product leaflets warn that nausea, vomiting and diarrhoea can cause dehydration, and the Mounjaro leaflet says this may lead to a decrease in kidney function. Creatinine and eGFR show kidney function; cystatin C is less affected by muscle mass, which can help when weight and muscle are changing.
Eating much less can lower intake of nutrients such as iron, B12 and folate, so they are worth checking at baseline and if you feel unusually tired. A low result is a reason to speak to your prescriber or GP, not to start high-dose supplements on your own.
A UCL study published in BMC Medicine in January 2026 estimated that about 1.6 million adults in England, Wales and Scotland (2.9%) used drugs such as Wegovy and Mounjaro for weight loss between early 2024 and early 2025, based on a survey of 5,260 adults. Women used them at about twice the rate of men.
Follow your prescriber's plan first. Many people test once before starting and again after about three months, when HbA1c reflects the new average (HbA1c reflects the last two to three months, Diabetes UK), then at longer intervals once stable. Test sooner if you feel unwell, and get urgent help for severe, persistent stomach pain.
Ultimate: 140 biomarkers including HbA1c, fasting insulin, ApoB, liver, kidney with cystatin C, iron, B12, folate and thyroid. £349 plus your draw. Clinician-reviewed report within 4 working days. Klarna and Clearpay at checkout.
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