Sniff test: can odors travel to the brain?

NCT ID NCT06370845

Knowledge-focused Sponsor: University Hospital, Basel, Switzerland Source: ClinicalTrials.gov ↗

First seen Jun 26, 2026 · Last updated Jun 27, 2026 · Updated 1 time

Summary

This early-phase study tests whether a natural odor, when inhaled, can be detected in the cerebrospinal fluid (the fluid around the brain and spine) within 30 minutes. 32 lean and obese adults who are already scheduled for a spinal tap will sniff either the odor or a placebo. The goal is simply to see if the odor molecules make it into the brain fluid, not to treat any condition.

What this could mean

Our plain-language read of the trial. This is informational only, not medical advice or a prediction.

Active substance: Natural odour (inhalation)
What this could lead to: If successful, this could show that odors inhaled through the nose can reach the brain fluid, opening new paths for delivering therapies to the brain.
What could go wrong: This is a very early, small study (32 people) that only checks if the odor appears in spinal fluid. It does not test any health benefit, and results may not apply to other odors or conditions.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Phase

Early phase 1

The earliest testing in people: a first look at safety, in a very small group.

Participants

About 32 people

The number the study aims to enrol. It can still change while the study runs.

Started

Apr 2026

Expected to finish

Oct 2027

An estimate. End dates often move.

Lead sponsor

Other sponsor

The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

18 to 60 years

Sex

Anyone

Healthy volunteers

Accepted

You do not need to have the condition being studied to take part.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria Obese Participants: * Age 18-60 years * Written informed consent * Scheduled for routine liquor puncture * BMI ≥ 30 kg/m2 * No proven diagnose of diabetes Inclusion Criteria Lean Participants: * Age 18-60 years * Written informed consent * Scheduled for routine liquor puncture * BMI 18-25 kg/m2 Exclusion Criteria: * Known allergy to the natural odour * Acute upper respiratory tract infection, acute or chronic sinusitis * Present or past surgical intervention of the nasal cavity, the paranasal sinus, the pituitary or the frontal brain * Pregnancy/lactation * Any kind of severe chronic disease (e.g. severe heart failure, active cancer disease, severe renal impairment with an estimated glomerular filtration rate \<30 ml/min/m2) * Inability to understand the study procedure and to sign the study consent

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Conditions

The condition(s) this trial relates to.

Obesity obesity disorder Overweight

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Overweight and obesity

How to take part

Only the study team decides who joins. These are the ways to reach them.

The places running it

2 sites. The list below names each one and where it is.
The official record

ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.

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A doctor treating you

A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.

Sniff test: can odors travel to the brain?

What the study statuses mean