DIMS Netherlands 2026: how to anonymously test drugs in the Dutch system

The Netherlands has something almost no other country offers: a nationally funded drug-checking system where you can get your sample analysed anonymously and for free. It is called DIMS — the Drugs Informatie en Monitoring Systeem — and it has been running since 1992. If you live in the Netherlands or pass through, this is the most reliable check you can get without ever giving your name. For international readers, it is also a useful model — and there is a postal alternative for non-residents at the bottom of this guide.

What DIMS is, in one paragraph

DIMS is a network of roughly 30 testing locations across the Netherlands, operated by addiction-care institutions (Jellinek, Brijder, Tactus, Novadic-Kentron, IrisZorg, Mondriaan, and others). You hand in a small sample, fill out a brief anonymous questionnaire, and receive the full laboratory analysis 1 to 2 weeks later. The lab is the Trimbos Institute in Utrecht, which analyses samples using gas chromatography / mass spectrometry (GC-MS) — the gold standard for substance identification and quantification.

DIMS accepts MDMA, cocaine, ketamine, 2C-B, LSD, amphetamine, GHB and research chemicals. Cannabis is not analysed by DIMS (other services exist for that).

What it costs

Nothing. Free for the user. It is funded by the Ministry of Public Health (VWS) via the Trimbos Institute. Some locations request a voluntary contribution of a few euros, but you are not required to pay. Compare that to international services like Energy Control (€50 per sample) and you understand why Dutch residents should use this.

Where to drop samples

The biggest, most reliable locations:

Jellinek Amsterdam — Hoogte Kadijk 64. Walk-in hours every Monday and Thursday evening.
Brijder Haarlem — Schoterweg 4. Brijder also runs satellite test points in The Hague, Leiden, Alkmaar, Hoorn and Zaandam.
Jellinek Utrecht — walk-in hours posted on Jellinek's website.
Tactus Enschede and Apeldoorn — covering the east.
Novadic-Kentron Eindhoven and 's-Hertogenbosch — covering Brabant.
VNN Groningen and Leeuwarden — covering the north.
IrisZorg Nijmegen and Arnhem — covering Gelderland.

Up-to-date locations and opening hours are on drugs-test.nl and the Jellinek website. Confirm before travelling — hours shift around holidays and summer.

How drop-off works

It is surprisingly low-friction:

Walk in. During open hours you simply enter. No ID, no name, no questions about who you are.
Hand over a small sample. For pills: usually a quarter pill, or the full pill if you have several. For powders: about 25–50 mg (the size of a pinhead). For blotters: one tab. For MDMA and cocaine powder you can hand over a little more so the lab can quantify.
Fill in the questionnaire. Fully anonymous. It asks what you thought it was, where you obtained it (shop / dealer / online / festival — no names), what you paid, and the colour / logo / shape for pills.
Take your test code. You receive a unique code which you later use to retrieve the result, typically by phone or via the website. No personal contact details are tied to it.
Wait 1–2 weeks. Some locations give a same-day reagent indication; the full GC-MS lab result takes 5 to 14 working days.

What gets measured

GC-MS analysis gives you two things no reagent test can:

Which active substances are present — not only whether it is MDMA, but whether PMMA, BMDB, methamphetamine, cathinones, 4-FA, 4-FMA or anything else has snuck in.
How much — the precise quantity of active substance in mg per pill or mg/g for powders. A 240 mg MDMA pill looks identical to an 80 mg one, but the difference between those two determines whether you peak gently or end up in the emergency department.

For MDMA pills you receive: active substance + dose + by-products. For cocaine: % cocaine + which adulterants + % of each (levamisole, phenacetin, lidocaine, caffeine, paracetamol — the usual Dutch suspects). For 2C-B, ketamine and research chemicals: identity + purity.

What DIMS does not do

Routine fentanyl screening. They can do it on request, but the Dutch market is largely fentanyl-free, so it is not the default panel. Ask explicitly if you are testing heroin or an unknown white powder.
Steroids, hormones, prescription pharma are outside DIMS scope.
Cannabis — not part of DIMS.
Counter-side reagent tests vary by location. The real analysis always comes from the lab.

How to read the result

You get a number, colour, and short description. Examples:

"MDMA, 187 mg per pill. No by-products detected." — What you want to see. High dose, so halve or quarter — 187 mg is strong for most people.
"MDMA 142 mg + caffeine 8 mg." — Caffeine as a by-product is common, not catastrophic, but explains why you race a bit harder than expected.
"MDMA 0 mg. Main constituent: cathinone (likely 3-MMC or similar)." — Not what you ordered. Do not take. Different drug, different risk profile.
"PMMA 95 mg + caffeine." — Immediate red flag. PMMA can be fatal at modest doses; treat as if it were on the Unity red list.

DIMS data is also published as trend analysis — anonymised and aggregated — and forms the basis of the Unity red list (see our Dutch pill warnings guide).

How often you can test

No limit. You can drop a fresh sample every week if you want. Most people only test new batches — the sensible default. If your supplier has come back clean five times in a row, you do not need to test every time, but MDMA pill batches can vary even from the same source.

What anonymity actually means

DIMS does not share personal data with police or the public prosecutor. Your name is recorded nowhere. The questionnaire is fully anonymised. The test code is your only link to the result — do not lose it.

Legally: DIMS operates under the Medical Treatment Agreement Act (WGBO) and the public-health framework, not under criminal procedure. This was explicitly negotiated between VWS and the Public Prosecutor decades ago to keep the threshold low. The sample itself is destroyed after analysis. Aggregated results are kept anonymously for the Unity trend monitor.

What to do with the result

Substance matches expectation, dose moderate (80–130 mg MDMA, <15% cocaine). See our first-time MDMA guide or safer cocaine guide for dose advice.
Substance matches, dose extreme (>180 mg MDMA per pill). Halve or quarter. Three or four spread across the night is safer than one whole pill at once.
Different substance than expected. Do not take. Give it away, dispose of it, or test the next batch.
Unknown substance or research chemical. Do not take until you know what it is and how it doses. DIMS can usually identify the compound; from there look up dosing on PsychonautWiki or with Unity.

If you cannot reach a Dutch test point

Some Brijder and Tactus sites accept samples via trusted intermediaries, but that is not the official channel. The official route is always in-person drop-off. International alternative: Energy Control in Spain accepts postal samples from across Europe, costs ~€50, and uses the same GC-MS analysis.

On-site testing at festivals

At major Dutch events (Mysteryland, Awakenings, Welcome to the Future) Unity — the prevention arm of Jellinek — runs sample tents. You do not get GC-MS on the spot, but you do get reagent testing plus a database-informed read of your pill colour/logo. It is not a replacement for lab analysis but a useful extra check.

Why DIMS matters internationally

In most countries you cannot legally hand drugs to a health worker for testing without exposing yourself to prosecution. The Netherlands crossed that bridge in the 1990s on a simple premise: people are going to use anyway, so let us at least make sure they know what they are using. Three decades of DIMS data have helped the country flag PMMA deaths, 4-MTA outbreaks and Superman pill batches faster than nearly any other European market. It is one of the cleanest evidence-based public-health programmes in the world.

If you are in the Netherlands and you use, you should be using DIMS.

FAQ

Is DIMS testing actually anonymous?

Yes. No ID, no name, no contact info. You receive a test code only you know. DIMS does not share data with police or prosecutors — this is fixed in law through the WGBO and a formal agreement between VWS and the Public Prosecutor.

How much does DIMS cost?

Nothing for the user. The system is funded by the Dutch Ministry of Public Health. Some locations accept voluntary donations of a few euros toward upkeep, but it is optional.

How long do DIMS results take?

Usually 5 to 14 working days. Some locations give a quick reagent indication at drop-off, but the full GC-MS analysis from the Trimbos lab takes 1 to 2 weeks.

Which drugs can be tested at DIMS?

MDMA, cocaine, amphetamine, ketamine, 2C-B, LSD, GHB, and most research chemicals. Cannabis is excluded. For heroin or unknown opioids you can request explicit fentanyl screening.

How much sample do I need to bring?

For pills: at least a quarter, ideally a whole pill if you have several. For powders: 25–50 mg, roughly a pinhead. For blotters: one tab.

Where are the DIMS locations?

About 30 across the Netherlands. The biggest sit at Jellinek (Amsterdam, Utrecht), Brijder (Haarlem, The Hague, Leiden, Alkmaar, Hoorn, Zaandam), Tactus (Enschede, Apeldoorn), Novadic-Kentron (Eindhoven, 's-Hertogenbosch), VNN (Groningen, Leeuwarden) and IrisZorg (Nijmegen, Arnhem). Live list on drugs-test.nl.

Can I mail a sample to DIMS from abroad?

Not officially — DIMS works through in-person drop-off at Dutch test points. If you cannot travel to the Netherlands, Energy Control in Spain accepts postal samples from across Europe and uses comparable lab methods.

Does DIMS test for fentanyl?

On request, yes. The Dutch market is largely fentanyl-free so it is not a default screening, but for suspicious white powders or heroin you can explicitly ask for fentanyl analysis.

What is the Unity red list?

A live warning list compiled from DIMS results. Pills or powders containing extreme doses or dangerous by-products like PMMA land on it. The list is published by Unity (Jellinek) — see our current Dutch pill warnings guide.