Stress Did Not Release Stored THC Into the Bloodstream of Regular Cannabis Users | Research

The takeaway

Despite causing measurable stress and mild fat breakdown, cold water immersion did not increase blood THC levels or produce intoxication in 15 regular cannabis users.

Cannabis users concerned about unexpected intoxication and researchers studying THC pharmacokinetics.

Zero increase in blood THC despite stress-induced fat breakdown

What the researchers found

Cold water immersion (10 minutes at 10 degrees C) produced a small but significant stress response (increased heart rate, blood pressure, decreased calmness) and increased plasma free fatty acids and glycerol. However, neither plasma THC nor its metabolite 11-COOH-THC increased, and no cognitive impairment or subjective intoxication was observed.

Why it matters

Animal studies suggested that stress-induced lipolysis could release fat-stored THC into circulation, potentially causing unexpected intoxication. This study found no evidence of this phenomenon in humans, which is reassuring for regular cannabis users in stressful situations.

The numbers in context

N = 15 (9 female). Cannabis use: 5.0 days/week. CWI: 10 min at ~10 degrees C. Significant increases in HR, systolic BP, FFA, and glycerol. No change in plasma THC, 11-COOH-THC, cognitive function, or subjective drug effects.

How the study worked

Single-arm trial with 15 regular cannabis users (5+ days/week, 9 female). Participants underwent cold water immersion as a stress intervention. Plasma cannabinoids, cognitive function, subjective drug effects, heart rate, blood pressure, and lipolysis markers were measured before, shortly after, and 2 hours after immersion.

What this study cannot tell us

Small sample (n=15). Only one type and duration of stress tested. The stress response and lipolysis were modest; more intense or prolonged stress might produce different results. Regular users only; results may not apply to occasional users with different fat storage patterns.

How to read the evidence

Small pilot study with controlled design. Provides initial human evidence but requires replication with different stress intensities and populations.

When this study was published

Published in 2025.

The bigger picture

The idea that stored THC could be spontaneously released during stress, exercise, or fasting has generated concern. This study provides the first controlled human evidence that brief acute stress does not release clinically meaningful amounts of stored THC.

Questions still open

Would more intense or prolonged stress produce THC release? Does exercise-induced lipolysis (which is more sustained) have different effects? Could this mechanism operate in individuals with higher body fat percentages?

Common questions

Can stress make you feel high from stored THC?

This study found no evidence of it. Despite causing measurable stress and fat breakdown, cold water immersion did not increase blood THC or produce any signs of intoxication in regular users.

Does this apply to drug testing?

The study measured plasma THC, not urine metabolites. While acute stress did not increase plasma THC, this does not address whether stress could affect urine drug test results, which measure different metabolites over longer windows.

Read the original research

Does acute stress induced via cold water immersion increase blood THC concentrations in regular cannabis users?

Psychopharmacology, 242(12), 2785-2799

View on PubMed ↗Publisher’s paper ↗

Citation

McCartney, Danielle; Levoux, Jordan; Gordon, Rebecca; Sharman, Laura; Walker, Katie; Arnold, Jonathon C; McGregor, Iain S. (2025). Does acute stress induced via cold water immersion increase blood THC concentrations in regular cannabis users?. Psychopharmacology, 242(12), 2785-2799. https://doi.org/10.1007/s00213-025-06833-8