High-dose oral CBD raised anandamide levels 1.6-fold, and adding THC boosted the effect to 2.1-fold | Research

The takeaway

A single 800 mg oral CBD dose increased serum anandamide 1.6-fold in healthy volunteers, while combining CBD with THC produced a 2.1-fold increase, suggesting the two cannabinoids have synergistic effects on endocannabinoid signaling.

People interested in how CBD and THC affect the endocannabinoid system and implications for mental health treatment.

2.1-fold anandamide increase with CBD + THC combination

What the researchers found

CBD at 800 mg (but not 600 mg) significantly increased serum anandamide (1.6-fold), OEA and PEA (1.4-fold). THC at 10 and 20 mg initially decreased anandamide but levels returned to baseline by 160 minutes. Combining CBD 800 mg + THC 20 mg produced the highest increases: anandamide 2.1-fold, OEA 1.9-fold, PEA 1.8-fold, without reaching a plateau.

Why it matters

In schizophrenia trials, CBD doses of 800 mg+ showed clinical benefit, and anandamide elevation has been linked to improvement. This study confirms the dose threshold for anandamide elevation and reveals that THC combination enhances the effect, providing a pharmacological rationale for specific dosing.

The numbers in context

75 healthy volunteers. CBD 800 mg: anandamide +1.6-fold, OEA/PEA +1.4-fold. CBD 600 mg: no significant effect. THC 10 mg: anandamide -1.3-fold initially. CBD 800 + THC 20: anandamide +2.1-fold, OEA +1.9-fold, PEA +1.8-fold.

How the study worked

Two independent parallel-designed clinical trials with 75 healthy volunteers. Single oral doses of CBD (600 or 800 mg), THC (10 or 20 mg), or CBD+THC combination. Serum endocannabinoid levels measured by LC-MS/MS at baseline, 65, and 160 minutes post-administration.

What this study cannot tell us

Single-dose study in healthy volunteers; chronic dosing may differ. Only two CBD doses tested (600 vs. 800 mg). Serum levels may not reflect brain endocannabinoid changes. Short measurement window (160 minutes).

How to read the evidence

Two parallel-designed clinical trials with objective biomarker outcomes. Limited by single-dose design and healthy volunteer population.

When this study was published

Published in 2024 in BMJ Mental Health.

The bigger picture

These findings provide a biological readout for CBD dosing in psychiatric treatment. The dose-dependent effect and the synergy with THC could help clinicians calibrate cannabinoid prescriptions for conditions where endocannabinoid signaling is relevant.

Questions still open

Would even higher CBD doses produce greater anandamide increases? Does the CBD-THC synergy on anandamide translate to enhanced clinical outcomes? Is the 2.1-fold anandamide increase clinically meaningful for psychiatric conditions?

Common questions

Does CBD raise endocannabinoid levels?

Yes, but only at higher doses. In this study, 800 mg CBD increased anandamide 1.6-fold while 600 mg had no significant effect, suggesting a dose threshold for this effect.

Does combining CBD and THC enhance the effect?

Yes. Combining 800 mg CBD with 20 mg THC produced the largest anandamide increase (2.1-fold), greater than either compound alone, suggesting synergistic effects on endocannabinoid signaling.

Read the original research

Dose-dependent effects of oral cannabidiol and delta-9-tetrahydrocannabinol on serum anandamide and related N-acylethanolamines in healthy volunteers.

BMJ mental health, 27(1)

View on PubMed ↗Publisher’s paper ↗

Citation

Couttas, Timothy A; Boost, Carola; Pahlisch, Franziska; Sykorova, Eliska B; Mueller, Juliane K; Jieu, Beverly; Leweke, Judith E; Dammann, Inga; Hoffmann, Anna E; Loeffler, Martin; Grimm, Oliver; Enning, Frank; Flor, Herta; Meyer-Lindenberg, Andreas; Koethe, Dagmar; Rohleder, Cathrin; Leweke, F Markus. (2024). Dose-dependent effects of oral cannabidiol and delta-9-tetrahydrocannabinol on serum anandamide and related N-acylethanolamines in healthy volunteers.. BMJ mental health, 27(1). https://doi.org/10.1136/bmjment-2024-301027