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Molecule guide

MDMA: what the research shows

Studied alongside therapy for PTSD, then turned down by the FDA in 2024. What the trials found, what regulators questioned, and how strong the evidence is.

ReviewedLast updated September 25, 2026

Also known as Midomafetamine, 3,4-methylenedioxymethamphetamine

At a glance

Type
Entactogen (sometimes called an empathogen). Chemically related to amphetamines. Not a classic psychedelic.
How it acts
Causes brain cells to release serotonin, noradrenaline and dopamine.
Approved uses
None in Canada or the US. Australia allows authorised psychiatrists to prescribe it for PTSD (since 2023).
Legal status
Controlled substance in Canada, with limited access through the Special Access Program. Schedule I in the US.
How it's given in research
Two or three supervised oral doses, each inside a long therapy session, alongside preparation and integration therapy.
Strongest evidence
PTSD, from two phase 3 randomised trials.
Biggest open question
Whether the trial results hold up to the concerns regulators raised about blinding, safety data and trial conduct.

Evidence by condition

How strong the research is for each use, on our four-level evidence scale.

PTSD Moderate

Two phase 3 randomised trials (90 and 104 people) found larger symptom reductions with MDMA plus therapy than with placebo plus the same therapy. In 2024, the FDA declined to approve it and asked for another phase 3 trial.

What it is

MDMA was first made in 1912 by the German company Merck. It wasn’t a medicine in its own right, just a minor step in making other compounds, and it wasn’t tested as a drug at the time.3 In the 1970s and early 1980s, some therapists used it to help clients open up. It then became widely used recreationally as “ecstasy” or “molly”, and the US banned it in 1985.6

In research today, MDMA is not given on its own. It’s used as a companion to psychotherapy, a combination called MDMA-assisted therapy.

How it works in the brain

MDMA causes brain cells to release serotonin, noradrenaline and dopamine, raising their levels in the brain.6 People commonly report feeling closer to others, less fearful and more able to talk about painful memories. The theory behind the PTSD trials is that this makes it easier to revisit trauma in therapy without being overwhelmed.

Key studies

Severe PTSD, 2021. In a phase 3 trial, 90 people with severe PTSD were randomised to MDMA or placebo. Both groups received the same therapy: three preparation sessions, three drug sessions and nine integration sessions. Two months later, PTSD scores had dropped by 24.4 points on average with MDMA, compared with 13.9 with placebo.1

Moderate to severe PTSD, 2023. A second phase 3 trial with 104 participants, a more diverse group, found similar results. Symptoms were measured by independent assessors who didn’t know which treatment people had received.2

The FDA decision, 2024. In August 2024, the FDA declined to approve MDMA-assisted therapy and asked for another phase 3 trial. Its advisory committee had raised concerns about functional unblinding, cardiovascular risks and how safety data were collected. The FDA also suggested an independent audit of the study records.4 The same month, a journal retracted three papers based on the earlier phase 2 trials, citing protocol violations at one Canadian trial site.5

Safety and risks reported in research

In the trials, common short-term effects included muscle tightness, nausea, reduced appetite and sweating. There were also temporary increases in blood pressure and heart rate. The 2021 trial reported no increase in abuse potential, suicidality or QT prolongation (a heart-rhythm change).1

  • Canada: A controlled substance under the Controlled Drugs and Substances Act.9 Since January 2022, physicians can request MDMA for individual patients with serious conditions through Health Canada’s Special Access Program, case by case.8
  • United States: Schedule I since 1985.6 The FDA declined approval in August 2024.4
  • Australia: Since July 2023, authorised psychiatrists can prescribe MDMA for PTSD.7

History in brief

  • 1912: First made at Merck, as an unimportant step in a chemical process.3
  • 1970s–early 1980s: Used by some therapists. Recreational use spreads.6
  • 1985: US places MDMA in Schedule I.6
  • 2021 and 2023: Two phase 3 PTSD trials published.12
  • 2022: Canada reopens Special Access Program requests.8
  • 2023: Australia allows authorised psychiatrists to prescribe it.7
  • 2024: FDA declines approval. Three phase 2 papers are retracted.45

Myths vs evidence

The claim“MDMA therapy was approved for PTSD in the US.”

What the evidence says False

In August 2024, the FDA declined to approve MDMA-assisted therapy for PTSD and recommended an additional phase 3 trial.4 It is not approved in Canada either. Australia is the main exception, where authorised psychiatrists can prescribe it.7

The claim“MDMA therapy is just taking ecstasy with a therapist.”

What the evidence says Misleading

In the phase 3 trials, participants received a measured dose of pure MDMA in a supervised session. This sat inside a structured program of three preparation sessions and nine integration sessions.1 Street ecstasy often contains other substances, and unsupervised use carries different risks.

The claim“The MDMA trials were flawless. The FDA just didn't like psychedelics.”

What the evidence says Misleading

Regulators raised specific concerns: participants could often tell whether they got MDMA (functional unblinding), questions about how safety data were collected, and cardiovascular risks.4 Separately, three papers based on the earlier phase 2 trials were retracted in 2024 over protocol violations at one site.5

See all myths vs evidence →

Frequently asked questions

Why is MDMA not called a classic psychedelic?

Classic psychedelics like psilocybin and LSD act mainly on serotonin 2A receptors and strongly change perception. MDMA works differently. It releases serotonin and other brain chemicals, and tends to increase feelings of closeness and emotional openness, with milder perceptual changes.

Why did the FDA turn down MDMA therapy?

The FDA said the data submitted weren't enough to approve it and asked for another phase 3 study. Its advisory committee had raised concerns about functional unblinding, cardiovascular risks and how safety information was collected. The FDA also suggested an independent audit of the study records.

Can you get MDMA therapy legally in Canada?

Only in limited ways. Since 2022, a physician can apply to Health Canada's Special Access Program for an individual patient with a serious condition, and clinical trials are running. Talk to a qualified health professional about your own situation.

Who was excluded from the MDMA trials?

The phase 3 trials required participants to stop psychiatric medications first, and excluded people with certain heart conditions, psychotic disorders and some other conditions. That means results may not apply to everyone with PTSD.

Clinical trials

Showing 8 of 33 active trials in our tracker.

See all trials in the tracker →

References

  1. Mitchell JM, et al. MDMA-assisted therapy for severe PTSD: a randomized, double-blind, placebo-controlled phase 3 study. Nature Medicine. 2021;27(6):1025–1033. Source
  2. Mitchell JM, et al. MDMA-assisted therapy for moderate to severe PTSD: a randomized, placebo-controlled phase 3 trial. Nature Medicine. 2023;29(10):2473–2480. Source
  3. Freudenmann RW, Öxler F, Bernschneider-Reif S. The origin of MDMA (ecstasy) revisited: the true story reconstructed from the original documents. Addiction. 2006;101(9):1241–1245. Source
  4. Psychiatric Times. FDA releases Complete Response Letter on declining MDMA-assisted therapy for PTSD. 2025. Source
  5. STAT News. Three MDMA therapy papers retracted over ethics violations. August 11, 2024. Source
  6. Farrar AM, et al. Ecstasy, molly, MDMA: what health practitioners need to know about this common recreational drug. Disease-a-Month. 2025;71(3):101851. Source
  7. Therapeutic Goods Administration (Australia). Change to classification of psilocybin and MDMA to enable prescribing by authorised psychiatrists. 2023. Source
  8. Canada Gazette, Part II. Regulations Amending Certain Regulations Relating to Restricted Drugs (Special Access Program), SOR/2021-271. January 5, 2022. Source
  9. Government of Canada. Controlled Drugs and Substances Act (S.C. 1996, c. 19). Source