From promising postpartum depression treatments to groundbreaking neuroscience research, here’s what’s at stake — and why SSDP is pushing back.

SSDP has submitted a formal public comment urging the Drug Enforcement Administration (DEA) to withdraw its proposal to place five tryptamines into Schedule I of the Controlled Substances Act.

Tryptamines are a family of chemical compounds, some of which produce psychedelic effects by interacting with serotonin receptors in the brain. While these five substances share certain chemical characteristics, they have different effects, different research applications, and different levels of scientific evidence supporting their potential uses.

Some are already being investigated in human clinical trials. Others could help scientists better understand neurological conditions, psychiatric disorders, and the fundamental workings of the brain.

Our message to the DEA is simple: We need more research, not more restrictions.

What Are the Five Tryptamines, and Why Do They Matter?

The DEA’s proposal would affect five distinct compounds, each with its own scientific profile and potential applications.

1. 4-OH-DiPT: A Potential Breakthrough for Postpartum Depression

4-Hydroxy-N,N-Diisopropyltryptamine (4-OH-DiPT) is particularly important because of its connection to an investigational treatment for postpartum depression.

Reunion Neuroscience is developing luvesilocin (RE104), a shorter-acting prodrug of 4-OH-DiPT that has received FDA Breakthrough Therapy Designation for postpartum depression. That designation recognizes the potential for an investigational treatment to offer substantial improvement over existing options.

With the treatment advancing toward Phase 3 clinical trials, SSDP is concerned that the DEA’s proposed restrictions could introduce new regulatory barriers and uncertainty for researchers developing treatments for a serious condition.

2. 5-MeO-MiPT: Already Being Studied in Humans

5-Methoxy-N-Methyl-N-Isopropyltryptamine (5-MeO-MiPT) is another compound with active clinical research underway.

MindState Design Labs has studied its formulation, MSD-001, in a Phase 1 clinical trial involving 47 healthy participants. The study reported that the formulation was well tolerated across the tested dose ranges.

While this doesn’t establish that 5-MeO-MiPT is an effective treatment for any condition, it demonstrates that meaningful human research is already taking place. Additional studies could help researchers better understand its safety, pharmacology, and possible therapeutic applications.

3. DiPT: A Window Into How the Brain Hears

N,N-Diisopropyltryptamine (DiPT) stands out for a fascinating reason: unlike psychedelics more commonly associated with changes in visual perception, DiPT is known for its unusual effects on how people perceive sound.

That makes it potentially valuable for neuroscience research into auditory processing.

Scientists could use this compound to investigate how the brain interprets sound and potentially improve our understanding of conditions such as tinnitus (persistent ringing or other sounds in the ears) and diplacusis (hearing the same sound at different pitches).

These applications remain exploratory, but restricting access to DiPT could make answering these scientific questions more difficult.

4. 5-MeO-AMT: Understanding Serotonin and the Brain

5-Methoxy-alpha-Methyltryptamine (5-MeO-AMT) has a relatively long duration of action and distinctive psychedelic and stimulant-like effects.

Its unusual pharmacological characteristics make it potentially useful for studying serotonin signaling, which plays an important role in mood, sleep, appetite, and neurological functioning.

Preliminary animal research has also raised questions about its abuse potential that deserve further investigation. SSDP argues that those questions should be answered through compound-specific scientific evidence rather than assumptions based on chemical similarities to other drugs.

5. 5-MeO-DET: An Opportunity to Learn More

Of the five substances, 5-Methoxy-N,N-Diethyltryptamine (5-MeO-DET) remains one of the least understood.

Scientists have limited information about its effects in humans, safety profile, patterns of use, and possible research applications.

But that’s precisely why further investigation matters.

As SSDP argues in our public comment, a lack of evidence should not automatically justify imposing the most restrictive drug classification. Doing so could create a cycle in which research is restricted because evidence is limited, while those same restrictions make it harder to produce the missing evidence.

The Bigger Problem: When Drug Scheduling Gets in the Way of Science

Schedule I is the most restrictive classification under federal drug law. It applies to substances determined to have a high potential for abuse, no currently accepted medical use in treatment in the United States, and a lack of accepted safety for use under medical supervision.

For researchers, Schedule I restrictions can mean additional licensing requirements, regulatory delays, increased costs, and barriers to obtaining research materials. These obstacles can discourage scientific investigation and slow the development of potential treatments.

SSDP’s public comment emphasizes that the DEA must evaluate each substance individually, using evidence specific to its pharmacology, risks, and potential applications.

The proposal also raises questions about federal research priorities. Executive Order 14401 calls for accelerating research and appropriate patient access to investigational psychedelic treatments for serious mental health conditions. SSDP argues that introducing additional scheduling restrictions could undermine those objectives.

And the consequences extend beyond the laboratory. Prohibition can drive drug markets underground, where accurate labeling, quality controls, and reliable safety information are often missing.

That’s why SSDP is calling on the DEA to withdraw the proposed scheduling, reconsider its scientific analyses, consult with the FDA and other federal health experts, and explicitly account for the potential harms to scientific research before making any final decision.

Drug policy should protect public health, not prevent scientists from developing the knowledge needed to improve it.

Thank You for Making Your Voices Heard!

We also want to extend a huge thank-you to everyone who used SSDP’s public comment tool to submit their own comments to the DEA!

Public participation is an essential part of the federal rulemaking process. Every researcher, student, patient advocate, healthcare professional, and concerned community member who took the time to engage helped bring additional perspectives into a decision with potentially far-reaching consequences.

We’re especially grateful to the scientists and members of the SSDP Family who continue to make the case for evidence-based drug policy and the importance of protecting scientific freedom.

The public comment period may be over, but our work isn’t. SSDP will continue following this proposal, engaging with researchers and policymakers, and challenging drug scheduling decisions that create unnecessary barriers to science.

Help Us Keep Science Moving Forward

Challenging harmful drug scheduling decisions takes more than submitting a public comment.

It takes scientists willing to share their expertise, students and advocates willing to organize, and a grassroots network capable of bringing those voices into federal policy debates.

From challenging the scheduling of DOI and DOC to defending research access for these five tryptamines, SSDP is working to ensure that drug policy is shaped by science, compassion, and human rights — not fear or outdated assumptions.

Your donation helps make that work possible.

Support SSDP’s scientific advocacy, grassroots organizing, and efforts to protect the future of psychedelic research.

Donate to SSDP Because scientific progress shouldn’t be another casualty of the War on Drugs.

Read SSDP’s full public comment on the DEA’s proposed scheduling of five tryptamines: [Embed full public comment PDF here].