THC and CBD Directly Interfere With Calcium Channels in Human Sperm, Potentially Affecting Fertility
THC and CBD directly affected CatSper calcium channels in human sperm — the same channels essential for sperm activation by progesterone — with THC also altering sperm function in lab tests, raising concerns about cannabis effects on male fertility.
Quick Facts
What This Study Found
THC and CBD affected the sperm-specific CatSper calcium channel, suppressing its activation by progesterone (P4) and prostaglandin E1 (PGE1). THC also altered human sperm function in vitro. These effects occurred through direct action on the ion channel rather than through cannabinoid receptors.
Key Numbers
THC and CBD both suppressed CatSper activation by progesterone (P4) and prostaglandin E1 (PGE1). THC altered sperm function in vitro. Effects occurred through direct ion channel action, not cannabinoid receptors.
How They Did This
In vitro study testing THC, CBD, and their major metabolites on calcium influx via CatSper channels in human spermatozoa. Calcium signaling measured in response to progesterone and prostaglandin stimulation with and without cannabinoid pre-treatment.
Why This Research Matters
CatSper is the primary calcium channel driving sperm toward the egg — it's essential for fertilization. If THC and CBD suppress this channel, cannabis use by men trying to conceive could directly impair their fertility at the cellular level.
The Bigger Picture
Previous studies have shown cannabis can affect semen parameters (count, motility), but the mechanism was unclear. This study identifies a specific molecular target — the CatSper channel — providing the first direct evidence of how phytocannabinoids may impair the fertilization process itself.
What This Study Doesn't Tell Us
In vitro study — lab conditions may not reflect concentrations in reproductive tract after cannabis use. Metabolite effects may differ from parent compounds in vivo. Only acute effects tested. Human studies on fertility outcomes needed.
Questions This Raises
- ?What concentration of THC/CBD reaches the reproductive tract after cannabis use?
- ?Is the CatSper suppression reversible with cannabis cessation?
- ?Could this mechanism explain some cases of unexplained male infertility in cannabis users?
Trust & Context
- Key Stat:
- Evidence Grade:
- In vitro mechanistic study providing molecular evidence, but concentrations and conditions may not reflect in vivo exposure during cannabis use.
- Study Age:
- Published 2025.
- Original Title:
- The major phytocannabinoids, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), affect the function of CatSper calcium channels in human sperm.
- Published In:
- Human reproduction (Oxford, England), 40(5), 796-807 (2025)
- Authors:
- Wehrli, Lydia, Altevogt, Hannah, Brenker, Christoph, Zufferey, Fanny, Rossier, Michel F, Strünker, Timo, Nef, Serge, Rahban, Rita
- Database ID:
- RTHC-07933
Evidence Hierarchy
Frequently Asked Questions
Can cannabis affect male fertility?
This study provides direct evidence that THC and CBD suppress the CatSper calcium channel that sperm need for fertilization. While this is lab-based evidence, men trying to conceive may want to discuss cannabis use with their fertility specialist.
Does CBD also affect sperm, not just THC?
Yes — both THC and CBD suppressed CatSper channel activation by progesterone. This means even non-intoxicating CBD products could potentially affect sperm function, though real-world concentrations reaching the reproductive tract are unknown.
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Cite This Study
https://rethinkthc.com/research/RTHC-07933APA
Wehrli, Lydia; Altevogt, Hannah; Brenker, Christoph; Zufferey, Fanny; Rossier, Michel F; Strünker, Timo; Nef, Serge; Rahban, Rita. (2025). The major phytocannabinoids, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), affect the function of CatSper calcium channels in human sperm.. Human reproduction (Oxford, England), 40(5), 796-807. https://doi.org/10.1093/humrep/deaf020
MLA
Wehrli, Lydia, et al. "The major phytocannabinoids, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), affect the function of CatSper calcium channels in human sperm.." Human reproduction (Oxford, 2025. https://doi.org/10.1093/humrep/deaf020
RethinkTHC
RethinkTHC Research Database. "The major phytocannabinoids, delta-9-tetrahydrocannabinol (T..." RTHC-07933. Retrieved from https://rethinkthc.com/research/wehrli-2025-the-major-phytocannabinoids-delta9tetrahydrocannabinol
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.