MDMA

MDMA (also known as ecstasy or molly) is a synthetic psychoactive drug known for producing feelings of euphoria, emotional closeness, and heightened sensory experiences. While it's often perceived as a "safer" party drug, MDMA carries real risks—and those risks vary dramatically based on how you use it, where you use it, and what precautions you take.

This page is an interactive tool to help you understand the evidence-based risks of MDMA use. Your choices below will adjust the risk estimates to reflect your situation.

Your Choices

What is your biological sex?

What environment will you be in?

What level of dosage are you taking?

Are you combining MDMA with other substances?

What harm reduction practices will you follow?

Your Estimated Risks

Select risk factors above...

Data, Models and References

Baseline Factors

Biological Sex

MDMA:SexFactor
Sex_Description	Sex_Hyponatremia_Multiplier
Female	8.9
Male	1

Women are significantly more susceptible to MDMA-induced hyponatremia (low sodium from water intoxication). In one study, 26.7% of women using ecstasy at a rave developed hyponatremia compared to 3% of men. This is thought to be due to hormonal differences affecting brain cell volume regulation and the effects of antidiuretic hormone.

As such, the 8.9 multiplier comes from the relative risk ratio of 26.7/3.

Environment

MDMA:EnvironmentFactor
Environment_Description	Environment_Multiplier	Environment_Hyperthermia_Risk
Controlled setting (cool, calm, seated)	1	Low
Social gathering (moderate activity, climate-controlled)	1.5	Low
Club/concert (dancing, crowded, air-conditioned)	2.5	Moderate
Rave/festival (intense dancing, hot, crowded, poor ventilation)	5	High

Hot, crowded environments with physical exertion dramatically increase the risk of hyperthermia. MDMA raises core body temperature by 0.2-0.8°C in controlled settings, but in rave conditions with dancing, temperatures can rise by 1.8°C or more. Temperatures above 40°C can be fatal.

Dose

MDMA:DoseFactor
Dose_Description	Dose_Multiplier	Dose_mg
Microdose	0.5	< 1.0 mg/kg
Low Dose	0.7	1.0 - 1.3 mg/kg
Medium	1.0	1.3 - 1.5 mg/kg
High	1.5	1.6 - 2.0 mg/kg
Very High	2.0	> 2.0 mg/kg

The recommended harm-reduction dose is approximately 1-1.5 mg per kg body weight, with a maximum of 120 mg. Higher doses significantly increase risk of adverse effects. Modern ecstasy pills often contain 150-200 mg of MDMA, well above safe thresholds.

Polydrug Use

MDMA:PolydrugFactor
Polydrug_Description	Polydrug_Multiplier
MDMA only (tested)	1
MDMA only (untested)	1.5
MDMA with alcohol	2.5
MDMA with other stimulants	3
MDMA with multiple substances	5

The majority (75-87%) of MDMA-related deaths involve other substances. Alcohol increases risk of both hyperthermia and hyponatremia. Untested substances may contain dangerous adulterants like PMA/PMMA. In Australia, only 14% of MDMA-related deaths involved MDMA toxicity alone.

Harm Reduction Practices

MDMA:HarmReductionFactor
HarmReduction_Description	HarmReduction_Multiplier
Full protocol (tested, breaks, proper hydration, buddy system)	0.5
Partial (some precautions taken)	0.75
Minimal (few or no precautions)	1
None (reckless use)	1.5

Following harm reduction practices significantly reduces risk: test the substance, take regular cooling breaks (every 30-60 minutes), drink about 500ml water per hour (not more), avoid redosing, and use with trusted friends who can monitor you.

Risk Models

RiskModel: MDMA:AcuteIncidentRisk
Content: 
===Acute Health Incident Risk (per session)===
Based on your selections, your estimated risk of a '''moderate to severe acute health incident''' requiring medical attention is approximately '''{{One_In_X|{{#expr: (1/900) * {Environment_Multiplier} * {Dose_Multiplier} * {Polydrug_Multiplier} * {HarmReduction_Multiplier} }} }}''' per session.

Calculation: The baseline risk in the Netherlands is estimated at 1 in 900 pills for a moderate-to-severe acute health incident. This is adjusted by multipliers for environment, dose, polydrug use, and harm reduction practices.

Fatal and non-fatal health incidents related to recreational ecstasy use | PMC (van Amsterdam et al., 2020)

RiskModel: MDMA:HyperthermiaNarrative
Content: 
===Hyperthermia (Overheating) Risk===
{{#switch: {Environment_Hyperthermia_Risk}
|Low=Your hyperthermia risk is '''low''' in a controlled environment. MDMA typically raises body temperature by 0.2-0.8°C, which is manageable if you stay cool and hydrated.
|Moderate=Your hyperthermia risk is '''moderate'''. Dancing in a club environment can raise body temperature significantly. Take regular breaks to cool down.
|High=Your hyperthermia risk is '''elevated'''. Intense dancing in hot, crowded environments is the primary cause of MDMA-related deaths. Take breaks every 20-30 minutes, find cool areas, and monitor for warning signs (confusion, not sweating despite heat, rapid heartbeat).
|'''Unknown''' - please select an environment above.
}}

Hyperthermia is the leading cause of MDMA-related fatalities. In fatal cases, body temperatures of 40-42°C have been recorded. The risk increases dramatically with physical activity in hot environments.

Effects of MDMA on body temperature in humans | PMC

RiskModel: MDMA:HyponatremiaNarrative
Content: 
===Hyponatremia (Water Intoxication) Risk===
{{#ifexpr: {Sex_Hyponatremia_Multiplier} > 1
|As a '''woman''', you are at significantly elevated risk for hyponatremia. In one study, 26.7% of women using MDMA at a rave developed low sodium levels, compared to 3% of men. '''Do not drink more than 500ml of water per hour.''' If you're not sweating heavily, drink less. Warning signs include headache, nausea, confusion, and swelling.
|As a '''man''', your hyponatremia risk is lower but not zero. Stick to approximately 500ml of water per hour. Warning signs include headache, nausea, and confusion.
}}

Hyponatremia occurs when excessive water intake dilutes blood sodium levels. MDMA impairs the body's ability to regulate water balance. The condition can cause brain swelling, seizures, coma, and death. Most cases involve women under 30.

RiskModel: MDMA:MortalityRisk
Content: 
===Mortality Risk===
Based on your selections, your estimated mortality risk is approximately '''{{One_In_X|{{#expr: (2/100000) * {Environment_Multiplier} * {Dose_Multiplier} * {Polydrug_Multiplier} * {HarmReduction_Multiplier} }} }}''' per session.

For context, this compares to baseline estimates of:
* '''MDMA alone''': ~2 per 100,000 users annually
* '''Alcohol''': ~50 per 100,000 users annually
* '''Tobacco''': ~400 per 100,000 users annually

Calculation: Baseline mortality is estimated at approximately 2 deaths per 100,000 MDMA users per year when MDMA is the only substance used. This is adjusted by risk factor multipliers. Note that the vast majority (75-87%) of MDMA-related deaths involve polydrug use.

Long-Term Considerations

Unlike the acute risks above, long-term effects of MDMA are harder to quantify but should be considered:

Serotonin System Effects: Research suggests MDMA can cause lasting changes to the serotonin system, particularly with heavy or frequent use. Some studies show reduced serotonin transporter binding that may persist for years after stopping use.

Cognitive Effects: Some studies report memory and attention deficits in heavy MDMA users, though it's difficult to separate MDMA effects from polydrug use and pre-existing differences.

The "Comedown": Many recreational users report low mood, irritability, and fatigue 2-5 days after use (sometimes called "Suicide Tuesday"). However, clinical studies administering MDMA in controlled settings show no such effect. The "midweek blues" observed in recreational users may be largely explained by confounding factors—sleep deprivation, polydrug use, physical exhaustion, and dehydration—rather than MDMA's pharmacology alone.

Frequency Recommendation: Harm reduction experts recommend waiting at least 1-3 months between uses to allow the serotonin system to recover.

Initially created by Claude.