Losing weight the smart way starts with a blood test
Blood testing for people losing weight with medication — or about to start. Assessed by a registered physician. At 700+ sample locations across the Netherlands, no referral needed.
Measure along with your journey
A baseline test before you start, a follow-up at 3 months, and a comprehensive blood test at 6 months. So you know you're losing weight safely — and that it's working.
Build your own test
Choose from 103 biomarkers and only pay for what you want tested. No unnecessary markers, clear results.
From order to report in 4 steps
No waiting, no referral. Just order and go.
Choose your test
Choose your baseline test or follow-up, or build a custom test.
Receive your lab referral
You'll receive an email from ZorgDomein with a barcode within 1 business day. Orders placed outside office hours are processed from the next business day.
Get tested at a lab near you
Show the barcode on your phone and bring a valid ID. Done in under 15 minutes.
Receive your report from the doctor
A BIG-registered physician reviews your results and writes a personal report. On your dashboard within a few business days.
Close to home, carefully selected
700+ carefully selected locations across the Netherlands. Always near you.
Why SlimmerLab
Five things you get with every test
Losing weight on medication changes more than your weight. This is what we track alongside it — and what that rests on.
Every value explained, with its range beside it
Each result shows the measured number, its unit and the reference range that belongs with it — plus what the value means. That matters most when you are eating less, because some values drop before you notice anything.
Three values that drop first
These are the ranges as they appear in your report — next to each of your own results, so you can see whether you are still inside them.
Your pancreas, liver and kidneys, too
Weight-loss medication calls for more than a scale. Our tests include amylase and lipase (pancreas), liver values and kidney function — values most standard panels skip.
These sit inside the Safe Weight Loss panel, not as a separate add-on.
No referral needed, no waiting list
You order your test yourself. No trip to the GP first, no waiting list, and no conversation beforehand about why you want this checked alongside your medication.
Order today and get your blood drawn whenever it suits you.
Get tested near you
You choose where to have your blood drawn. Every collection point is on the map with its opening hours — useful when you come back every three months for a follow-up.
700+ collection points across the Netherlands.
Reviewed by a BIG-registered physician
Your results are reviewed by a physician registered in the Dutch BIG register. That applies to your baseline and to every follow-up after it.
The BIG register is public. You can check whether a physician is in it yourself.
See what is actually changing in your blood
The scale moves slowly. Your blood values show sooner whether you are on the right track, with a doctor explaining every measurement.
Understand Your Health Markers
Dive deep into what each biomarker measures, why it matters for your health, and what your results mean.
What does Insulin mean?
This test measures baseline insulin levels in a fasting state.
Unit pmol/L Read about Insulin MetabolicWhat does Glucose mean?
This test measures blood glucose after fasting for at least 8 hours.
Normal value 3,5 – 5,5 mmol/l Read about Glucose VitaminsWhat does Folate mean?
This test measures the level of folate (vitamin B9) in your blood.
Normal value 10 – 42 nmol/l Read about Folate LiverWhat does Lipase mean?
Lipase is an enzyme produced primarily by the pancreas that plays an essential role in fat digestion.
Unit u/l Read about LipaseThe reading table
Calm, reliable articles about losing weight, your metabolism, and your blood values. Written to be clear, not alarming.
Elevated liver values: what can the causes be?
What elevated liver values can mean, which causes are common after 60 and when to contact your GP.
Read moreStart your journey with confidence
Order your baseline test and get tested this week at a location near you. Personal report from a doctor, within a few business days.
Order your test
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700+ sample locations across the Netherlands
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Personal report from a doctor
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Report within a few business days
Frequently Asked Questions
About testing during your weight-loss journey, your results, and the process.