THC metabolite 11-OH-THC was up to 31 times more potent than THC in mice, with sex differences in rats
The primary psychoactive metabolite of THC (11-OH-THC) was 7 to 31 times more potent than THC across multiple measures in mice, and THC was significantly more potent in female rats than males.
Quick Facts
What This Study Found
11-OH-THC showed 7- to 31-fold greater potency than THC for catalepsy and hypothermia in mice and 7- to 9-fold greater potency in drug discrimination. Female rats were significantly more sensitive to THC than males. THC discriminative stimulus effects were stable across 17 months of aging in mice.
Key Numbers
11-OH-THC potency vs. THC: 7-15x for catalepsy, 7-31x for hypothermia, 7-9x in drug discrimination. 11-OH-THC affinity: ~1.5x higher than THC. Aging period: 17 months with stable THC discrimination.
How They Did This
Compared THC and 11-OH-THC using CB1 receptor binding assays, GTPgS functional assays, and in vivo behavioral tests (catalepsy, hypothermia, drug discrimination) across ICR mice, C57Bl/6J mice, and Sprague-Dawley rats of both sexes.
Why This Research Matters
When cannabis is eaten rather than smoked, more THC is converted to 11-OH-THC through first-pass liver metabolism. Understanding this metabolite's greater potency helps explain why edibles can produce stronger effects.
The Bigger Picture
These findings have direct implications for cannabis edible dosing and may help explain why women often report stronger effects from cannabis than men.
What This Study Doesn't Tell Us
Animal study using intraperitoneal injection, not oral consumption. Cross-species differences complicate human extrapolation. Limited behavioral measures.
Questions This Raises
- ?Do sex differences in THC metabolism explain why women report stronger cannabis effects?
- ?Should edible cannabis dosing guidelines account for the potency of 11-OH-THC?
Trust & Context
- Key Stat:
- 11-OH-THC was up to 31x more potent than THC in hypothermia measures
- Evidence Grade:
- Rigorous pharmacological study across multiple species and assays, but animal models have limited direct human applicability.
- Study Age:
- Published in 2021.
- Original Title:
- Sex, species and age: Effects of rodent demographics on the pharmacology of ∆9-tetrahydrocanabinol.
- Published In:
- Progress in neuro-psychopharmacology & biological psychiatry, 106, 110064 (2021)
- Authors:
- Wiley, Jenny L(13), Barrus, Daniel G(2), Farquhar, Charlotte E(2), Lefever, Timothy W, Gamage, Thomas F
- Database ID:
- RTHC-03613
Evidence Hierarchy
Tests effects in animals (usually mice or rats), not humans.
What do these levels mean? →Frequently Asked Questions
Why are cannabis edibles often stronger than smoking?
When THC is eaten, the liver converts more of it into 11-OH-THC, which this study found is 7-31 times more potent than THC itself in animal models.
Are there sex differences in THC sensitivity?
In rats, female animals were significantly more sensitive to THC than males, though this sex difference was not seen in mice, suggesting species-specific effects.
Read More on RethinkTHC
- THC-amygdala-anxiety-brain
- anandamide-weed-withdrawal
- cannabinoid-receptors-recovery-time
- cannabis-developing-brain-teenagers
- cant-enjoy-anything-without-weed
- dopamine-recovery-after-quitting-weed
- endocannabinoid-system-explained-simply
- endocannabinoid-system-withdrawal
- nervous-system-weed-withdrawal-fight-flight
- teen-weed-use-under-18-effects-brain
- thc-brain-withdrawal
- thc-prefrontal-cortex-brain-effects
- weed-cortisol-stress-hormones
- weed-memory-loss-recovery
- weed-motivation-amotivational-syndrome
- weed-nervous-system-effects
- weed-reward-system-brain
Cite This Study
https://rethinkthc.com/research/RTHC-03613APA
Wiley, Jenny L; Barrus, Daniel G; Farquhar, Charlotte E; Lefever, Timothy W; Gamage, Thomas F. (2021). Sex, species and age: Effects of rodent demographics on the pharmacology of ∆9-tetrahydrocanabinol.. Progress in neuro-psychopharmacology & biological psychiatry, 106, 110064. https://doi.org/10.1016/j.pnpbp.2020.110064
MLA
Wiley, Jenny L, et al. "Sex, species and age: Effects of rodent demographics on the pharmacology of ∆9-tetrahydrocanabinol.." Progress in neuro-psychopharmacology & biological psychiatry, 2021. https://doi.org/10.1016/j.pnpbp.2020.110064
RethinkTHC
RethinkTHC Research Database. "Sex, species and age: Effects of rodent demographics on the ..." RTHC-03613. Retrieved from https://rethinkthc.com/research/wiley-2021-sex-species-and-age
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.