Source: Rucker et al., Journal of Psychopharmacology 2024 (doi:10.1177/02698811241246857)

Before any medicine is tested in patients, it's tested in healthy volunteers to learn how the body absorbs and clears it, how strong the effects are at different doses, and whether it's safe. This trial did that for BPL-003, Beckley Psytech's intranasal 5-MeO-DMT. Every later BPL-003 study in the Research series builds on it.

The study

Design: Phase 1, double-blind, randomized, placebo-controlled, single ascending dose trial (NCT05347849), run at Hammersmith Medicines Research in London.
Participants: 44 healthy adults aged 25-55, none of whom had used psychedelics before. 31 received BPL-003 and 13 received a placebo. Most were men (73%).
Screening: people with a personal or close family history of serious mental illness, past suicide attempts, seizures or substance problems, or anyone taking MAOIs, were excluded.
Doses: seven groups of up to seven people received 1, 2.5, 4, 6, 8, 10 or 12 mg, with a safety committee reviewing each dose level before moving to the next.
Support: two preparation visits with a trained psychedelic monitor, then dosing in a decorated room with relaxing music and guided breathing beforehand. A nurse and the monitor stayed present throughout, and an integration session followed two days later.

What it found

Timing in the body: the medicine was absorbed quickly, peaking in the blood about 4-15 minutes after dosing (typically around 8-10 minutes), and cleared fast, with a half-life of about 15-27 minutes. It was undetectable within 4 hours.
The experience: effects began within 2-10 minutes and generally faded completely within 45-90 minutes. How intense the experience felt closely tracked the level of medicine in the blood.
Depth: at 10 and 12 mg, 3 of 5 people in each group (60%) had a complete mystical experience, compared with at most 1 person in each lower-dose group. Ego dissolution also increased with dose.
Variation between people: some participants had intense experiences at 8 mg, while others didn't reach a full mystical experience at 12 mg.
What people described: a rapid onset, attention turning inward, an altered sense of time, intense emotion, and often some fear and a struggle to let go. Those who could relax into it often described floating in space, an ocean or a void, with peace, calm or bliss, and later recounted meaningful insights.
Willingness to repeat: 87% of those who received BPL-003 said they would accept the same or a higher dose again. The four who wouldn't described re-living painful memories, finding the experience unpleasant, or not finding it personally meaningful.

Safety

Overall: side effects occurred in 61% of people on BPL-003 versus 15% on placebo. Nearly 90% were mild and the rest moderate. There were no severe or serious events and no withdrawals.
Most common: nasal discomfort, nausea, vomiting and headache.
Heart and blood pressure: both rose briefly after dosing, with systolic blood pressure going above 160 in five people. All readings returned to normal within 90 minutes without treatment.
Psychological: no suicidal thoughts, and no signs of lasting visual disturbances or trauma symptoms at the one-week follow-up.
Challenging moments: fear and discomfort were most common in the first 10-15 minutes after dosing, and some participants had overwhelming emotional experiences.

Limitations

Only 4-5 people per dose level
Healthy volunteers in a hospital-like setting, so people with mental health conditions, or in other settings, may respond differently
With a medicine this strong, most participants likely knew whether they'd received it
Follow-up lasted only about a week
Funded by Beckley Psytech, with several authors employed by or consulting for the company

What this means, and doesn't

The trial established the basic profile that makes intranasal 5-MeO-DMT distinctive: a fast onset, a short and intense experience, and a body that clears it within hours. It also identified 8-12 mg as the range used in later patient trials.

Several findings echo careful ceremonial practice. People responded very differently to the same dose, which supports titrating to the individual rather than following a fixed protocol. The hardest moments clustered right at the beginning, which is why grounding, breathing and steady presence matter most then. And participants themselves highlighted how much preparation and trust in their monitors helped them feel safe.

This was a short, closely monitored study in carefully screened healthy people. It doesn't establish long-term safety, or safety for people with health conditions or on medications.

Research summaries are for education, not medical advice. Considering 5-MeO-DMT yourself?
Start with Safety & Screening.