Essential Blood Tests Before & During Medical Weight Loss
Weight loss medications are not vitamins.
They change how your body functions.
At Marylebone Diagnostic Centre, we see many patients start weight loss journeys with no baseline testing.
That is a risk.
This guide explains how to do weight loss safely, not blindly.
Why Weight Loss Should Always Start With Blood Tests
Modern weight loss treatments affect:
- Appetite signalling
- Blood sugar regulation
- Liver metabolism
- Kidney filtration
- Electrolyte balance
- Muscle mass
You may feel fine while internal stress is building.
Blood tests reveal what symptoms cannot.
Who Is This Safety Panel For?
This panel is designed for:
- People considering GLP-1 medications
- People already using weight loss injections
- Rapid weight loss programmes
- Repeated dieting cycles
- Unexplained side effects during weight loss
It is equally relevant for men and women.
The Hidden Risks of Weight Loss Medications
Weight loss drugs can:
- Mask muscle loss
- Alter kidney function
- Stress the liver
- Disrupt electrolytes
- Worsen vitamin deficiencies
Many side effects start biochemically, not symptomatically.
Testing early prevents escalation.
What Is the Weight Loss Safety Panel?
This is a comprehensive monitoring blood panel designed to protect health while losing weight.
It answers three key questions:
- Is your body safe to start?
- Is your body tolerating treatment?
- Are there early warning signs?
What We Test in the Weight Loss Safety Panel
Core Safety Blood Markers
| Test | Why It Matters |
|---|---|
| Full Blood Count (FBC) | Anaemia, infection patterns |
| Liver Function Tests | Drug metabolism |
| Kidney Function (Urea, Creatinine, eGFR) | Filtration and hydration |
| Electrolytes (Na, K) | Fluid balance |
| HbA1c | Blood sugar regulation |
| Fasting Glucose | Hypoglycaemia risk |
| Lipid Profile | Cardiometabolic risk |
| CRP | Inflammatory stress |
| Vitamin B12 | Neurological safety |
| Vitamin D | Muscle and immune support |
This panel provides a system-wide safety snapshot.
Why Liver Monitoring Matters During Weight Loss
The liver processes:
- Medications
- Fat breakdown products
- Hormones
Rapid weight loss increases liver workload.
Early changes in:
- ALT
- AST
- ALP
Often appear before symptoms.
Monitoring protects long-term metabolic health.
Kidney Function & Dehydration Risk
Weight loss treatments can reduce thirst signals.
This increases risk of:
- Dehydration
- Electrolyte imbalance
- Kidney stress
Monitoring eGFR and creatinine ensures:
- Safe dosing
- Adequate hydration
- Early intervention if needed
Blood Sugar Stability & GLP-1 Use
GLP-1 therapies affect insulin signalling.
Blood tests assess:
- Hypoglycaemia risk
- Insulin sensitivity improvement
- Long-term metabolic benefit
HbA1c shows trends.
Glucose shows current stability.
Both matter.
Muscle Loss – The Silent Weight Loss Risk
Weight loss is not always fat loss.
Without monitoring:
- Muscle mass may decline
- Metabolism may slow
- Long-term regain risk increases
Blood tests help identify:
- Nutritional deficiency
- Protein metabolism stress
- Inflammatory catabolism
Safe weight loss protects lean mass, not just the scale.
Vitamin & Nutrient Depletion
Reduced appetite can reduce nutrient intake.
Common deficiencies include:
- Vitamin B12
- Vitamin D
- Iron
Deficiencies worsen:
- Fatigue
- Hair loss
- Brain fog
- Exercise tolerance
Monitoring prevents avoidable setbacks.
Monitoring Frequency – What’s Sensible?
Recommended Schedule
| Stage | Testing Frequency |
|---|---|
| Before starting | Baseline panel |
| First 3 months | Monthly |
| Ongoing | Every 3–6 months |
Monitoring is protective, not excessive.
What This Panel Can and Cannot Do
This panel CAN:
- Detect early organ stress
- Guide safe continuation
- Prevent long-term complications
- Support sustainable weight loss
This panel CANNOT:
- Replace clinical supervision
- Guarantee side-effect-free treatment
- Diagnose eating disorders
Blood tests inform safer decisions.
Why Choose Marylebone Diagnostic Centre?
- Results within 24–42 hours
- On-site consultant review
- Private suites
- Discreet and confidential care
- CQC-accredited and aligned with Marylebone High Standard
- Optional teleconsultations for results
📍 73 Baker Street, London W1U 6RD
🚇 5-minute walk from Baker Street tube
🕗 Monday–Saturday, 8:00–16:00
📞 +44 7495 970109
Frequently Asked Questions
Yes. Many issues are silent initially.
Absolutely. Rapid lifestyle weight loss also stresses systems.
Most results return within 24–42 hours.
Yes. That is the purpose of monitoring.
Book Your Weight Loss Safety Panel Today
Weight loss should improve health.
Not compromise it.
Proper monitoring ensures:
- Safety
- Sustainability
- Long-term success










