1,25-dihydroxyvitamin D (calcitriol)
This test measures 1,25-dihydroxyvitamin D, the biologically active form of vitamin D. It is used to investigate calcium imbalance, kidney disease and...
A practical monitoring blood test bundle for people using (or considering) Mounjaro, Ozempic, or Wegovy. It checks key health areas that can be affected during weight loss and GLP-1 treatment.
Turnaround time
2-3 days
Professional phlebotomist comes to you
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SelectedThis is a blood test profile built to support safer use of GLP-1/GIP weight loss and diabetes injections such as Mounjaro (tirzepatide) and Ozempic/Wegovy (semaglutide). It focuses on the health systems most relevant when appetite drops, weight changes quickly, and side effects like nausea or dehydration occur.
The profile gives a structured snapshot of:
Blood sugar control
Kidney health and hydration balance
Liver health
Pancreatic health
Thyroid health
Inflammation
Key vitamins linked to energy and wellbeing
General blood health
These medications can be highly effective, but they change how your body processes food and how much you eat. That means your internal “baseline” can shift quickly, especially during early dose changes or rapid weight loss. A monitoring profile helps you spot problems early and avoid pushing through symptoms that should be checked.
Nausea, vomiting, diarrhoea, or low fluid intake can lead to dehydration, which may temporarily reduce kidney function. Even if you feel “fine,” blood markers can show whether your body is under strain.
This matters more if you:
Struggle to keep fluids down
Are prone to low blood pressure or dizziness
Use diuretics, NSAIDs, or other meds that can affect kidneys
Have pre-existing kidney concerns
Weight loss can improve fatty liver over time, but liver markers can also rise for unrelated reasons. A liver screen provides reassurance and flags patterns that need follow-up (especially if you have right-sided abdominal discomfort, itching, or jaundice-type symptoms).
GLP-1 medications carry warnings around pancreatitis. Most people will never experience this, but if you develop certain symptoms, checking pancreatic markers supports safer decision-making and helps clinicians assess urgency.
If you’re using these medications for weight loss, it’s still useful to understand insulin resistance trends. If you’re diabetic or pre-diabetic, it’s even more important, especially if other medicines are involved.
When food volume reduces, it’s easy to drift into low vitamin levels, especially if you’re skipping meals or struggling with protein intake. Deficiencies can affect:
Energy and fatigue
Mood and concentration
Hair quality and skin health
Recovery from training
General wellbeing
Fatigue, constipation, hair changes, low mood, and weight shifts aren’t always medication-related. Thyroid imbalance can overlap with the same symptoms, so testing helps separate “expected” from “needs attention.”
Common symptoms / reasons to test may include:
Persistent nausea, vomiting, or diarrhoea
Signs of dehydration (dry mouth, dizziness, dark urine, headaches)
Unusual tiredness, weakness, or “wired but exhausted” feeling
Constipation that doesn’t settle
New or worsening reflux/indigestion
Abdominal pain, especially severe or persistent
Pain that spreads to the back, or vomiting with strong abdominal pain
Yellowing of skin/eyes, dark urine, pale stools
Shakiness, sweating, or lightheadedness (possible low blood sugar, especially with diabetes meds)
Hair shedding or feeling “run down” during rapid weight loss
If you have severe abdominal pain, persistent vomiting, fainting, or jaundice symptoms, you should seek urgent medical care rather than relying on a routine blood test.
Safety-focused monitoring
Checks the main body systems clinicians consider when GLP-1 side effects appear.
Early warning signals
Flags patterns before they become bigger issues (for example, dehydration strain or emerging deficiency trends).
Supports smarter dose decisions
If results show stress patterns, you can pause and reassess instead of “pushing through.”
Better fatigue troubleshooting
Helps separate medication effects from low vitamins, thyroid imbalance, or general blood health issues.
Reassurance when you feel fine
Many people want objective confirmation that internal markers are stable while weight changes.
Clear baseline for progress tracking
You can compare future results to see what improved with weight loss and what needs support.
More targeted supplementation
Reduces guesswork and helps avoid unnecessary supplements that don’t match your needs.
Improves conversations with clinicians
A structured profile makes GP or prescriber discussions more specific and evidence-led.
Choose your nearest UK clinic
Attend in clinic and a clinician draws your blood sample
Receive your results once ready
Or, if you prefer convenience:
Pay £60 extra and a mobile phlebotomist can come to your home or hotel to take the sample
Both options are UK-wide
Your report is best understood in three simple outcome types: low, balanced, or elevated (based on UK laboratory reference ranges and clinical decision limits where relevant). Each area of the profile is interpreted in context, meaning “elevated” in one area might matter a lot, while in another it may be mild or temporary.
A “low” result usually means something is below the expected range or trending lower than ideal. In this profile, low results often relate to:
Reduced nutrient status (which can contribute to fatigue, low mood, hair shedding, or poor recovery)
Signs your body’s reserves may be dropping during reduced intake
Less commonly, low levels can reflect dilution from hydration changes or other physiological shifts
What this can mean for you:
You may benefit from adjusting nutrition (especially protein intake and micronutrients)
Your clinician may recommend targeted supplementation and a follow-up plan
If symptoms match the findings, addressing “low” markers can noticeably improve how you feel
“Balanced” means results sit within expected ranges and don’t show obvious red flags in the areas tested. This is reassuring, especially if you’re experiencing mild, expected side effects.
What this can mean for you:
Your body is coping well with appetite and weight changes
You can focus on consistency: hydration, protein, fibre, and steady habits
If symptoms continue despite balanced results, it may point to medication tolerance, dose strategy, or lifestyle factors rather than a measurable deficiency
An “elevated” result means something is above the expected range or suggests strain. In this profile, elevations may relate to:
Dehydration or reduced fluid intake affecting kidney markers
Liver stress patterns that need follow-up
Pancreatic marker elevations that should be taken seriously, especially if symptoms are present
Inflammation signals that may reflect infection, stress, or another inflammatory driver
What this can mean for you:
If you have concerning symptoms alongside elevated markers, medical review is important
Some elevations are temporary and settle with hydration and stabilising intake
Your clinician may advise repeat testing or additional investigations to confirm the cause
Simple steps to get your results
Choose your test online and book in seconds. Select your preferred clinic location or home visit option.
Attend one of our UK or London clinics, arrange a home nurse visit, or use a finger-prick kit where available.
Your sample is analysed by accredited UK laboratories, with secure results delivered directly to you.
Take control of your health with London Blood Tests
WhatsApp UsFollow these guidelines for accurate results
Where possible, attend your blood test between 7am and 12pm. Please wait until any short-term illness or infection has fully resolved before testing. Avoid intense exercise for 24–48 hours beforehand, as this can affect certain markers.
Fasting is not always required, but some tests may recommend it. If fasting is advised, avoid food for 8–12 hours before your appointment and drink water only. Stay well hydrated, as this helps with sample collection and accuracy.
Continue prescribed medications unless advised otherwise by your clinician. Avoid vitamin, mineral, or biotin supplements for at least 24–48 hours before your test, as these can interfere with results. If you are unsure about any medication or supplement, please let us know before your appointment.
For hormone-related tests, timing within your menstrual cycle may be important. If relevant, follow any specific guidance provided on your test page.
If you have any questions or special circumstances, our team is happy to advise before your appointment.
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