“About 20% of the MDMA wasn’t what people thought it was, but actually this potency issue is more common, particularly in the pill form of MDMA.”

Know Your Stuff first published a warning about the high-dose pills in 2018. General manager Casey Spearin told the Herald the harm-reduction agency has been detecting high-dose MDMA pills for nearly as long as they have been running their free and confidential drug checking services.

“In our 2024-25 testing season, we found 101 pressed pills that we estimated to contain two or more doses of MDMA (at least 150mg). These pills made up 4.2% of the total MDMA that we found.

“High-dose pressed pills will often have two or three standard doses of MDMA in them – though some have been detected with seven or more doses.”

The illicit classification of the narcotic market means substances can be unknowingly mixed with dangerous contaminants.

Spearin said “some substances which are a common substitute or additive to MDMA such as cathinones are active in much smaller quantities (about one-half to one-third that of MDMA) – so if someone unknowingly consumes these thinking they are MDMA they could be taking four or more doses”.

Determining the exact amount of MDMA in a pill isn’t possible with Know Your Stuff’s in-field technology, but the agency regularly updates its Pill Library with photographs and information on pills they have identified that were obtained as a trusted substance but were not what people thought.

Its standard harm reduction information for any pressed pill is to “start with a quarter to a half and wait at least an hour and a half before taking any more”.

Additionally, Helm warned that even within one pill, the potency can vary wildly. “We call this a chocolate chip cookie effect, where it might be inconsistent within the pill itself.”

For this reason, Helm said it was important to know the warning signs of any substances a user planned to consume, to help determine when they may need to seek medical help.

MDMA in particular carries a risk of overamping, which is a type of stimulant overdose.

“Imagine if you took one of these pills and also had some coffee or an energy drink or a different stimulant … that can result in things like a racing heart, agitation, paranoia, chest pain, those kinds of problems,” Helm said.

“At that point, you want to be considering calling for help.”

Spearin said the rapidly changing nature of New Zealand’s drug supply means “it only takes one dealer to turn up at a festival and start deceptively, or unknowingly, selling people ‘MDMA’ which actually contains something more harmful”.

“A lot of the drug harm this summer will come from high-risk drug practices, such as mixing drugs or taking very high doses. When we talk about ‘mixing drugs’, it’s worth remembering that alcohol and caffeine are also drugs.”