Quitting Cannabis Reverses DNA Changes in Sperm

Cannabis-associated changes in sperm DNA methylation, particularly at genes involved in heart and brain development, were significantly diminished after 77 days of abstinence.

Schrott, Rose et al.·Environmental epigenetics·2021·Preliminary EvidenceProspective Cohort
RTHC-03503Prospective CohortPreliminary Evidence2021RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Prospective Cohort
Evidence
Preliminary Evidence
Sample
Not reported

What This Study Found

Whole-genome bisulfite sequencing identified 163 CpG sites with significantly altered DNA methylation in cannabis users' sperm, concentrated at genes involved in cardiogenesis and neurodevelopment, and many of these changes were reversed after one spermatogenic cycle (77 days) of abstinence.

Key Numbers

163 CpG sites with significantly different methylation (p<10^-9); affected genes enriched for development, cardiogenesis, and neurodevelopment pathways; 77-day abstinence period (one spermatogenic cycle); significant reduction in methylation differences after abstinence.

How They Did This

Prospective cohort comparing sperm DNA methylation between cannabis users and non-user controls at baseline and after a 77-day abstinence period, using whole-genome bisulfite sequencing.

Why This Research Matters

This is the first evidence that cannabis-related epigenetic changes in sperm are reversible, suggesting that men planning to conceive could potentially reduce risks by abstaining for at least one full sperm development cycle.

The Bigger Picture

As epigenetic inheritance through sperm becomes better understood, the finding that cannabis effects are reversible provides a practical timeline for men who want to minimize potential reproductive risks.

What This Study Doesn't Tell Us

Small sample size; controlled abstinence period may not reflect real-world behavior; long-term offspring health effects of these epigenetic changes remain unknown; functional significance of methylation changes not established.

Questions This Raises

  • ?Do these reversed epigenetic changes translate to measurable differences in offspring health outcomes?
  • ?Is 77 days sufficient for complete reversal, or do some changes persist longer?

Trust & Context

Key Stat:
77 days of cannabis abstinence significantly reduced sperm DNA methylation changes at developmental genes
Evidence Grade:
Small prospective study using advanced genomic methods provides preliminary evidence for reversibility of epigenetic changes.
Study Age:
Published in 2021.
Original Title:
Refraining from use diminishes cannabis-associated epigenetic changes in human sperm.
Published In:
Environmental epigenetics, 7(1), dvab009 (2021)
Database ID:
RTHC-03503

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-ControlFollows or compares groups over time
This study
Cross-Sectional / Observational
Case Report / Animal Study

Enrolls participants and follows them forward in time.

What do these levels mean? →

Frequently Asked Questions

Does cannabis permanently change sperm DNA?

This study suggests not. After 77 days of abstinence (one full sperm development cycle), many of the cannabis-associated DNA methylation changes were significantly reduced.

Which genes were affected by cannabis use?

The 163 altered sites were concentrated at genes involved in early development, particularly heart formation and brain development, raising questions about potential effects on offspring.

Read More on RethinkTHC

Cite This Study

RTHC-03503·https://rethinkthc.com/research/RTHC-03503

APA

Schrott, Rose; Murphy, Susan K; Modliszewski, Jennifer L; King, Dillon E; Hill, Bendu; Itchon-Ramos, Nilda; Raburn, Douglas; Price, Thomas; Levin, Edward D; Vandrey, Ryan; Corcoran, David L; Kollins, Scott H; Mitchell, John T. (2021). Refraining from use diminishes cannabis-associated epigenetic changes in human sperm.. Environmental epigenetics, 7(1), dvab009. https://doi.org/10.1093/eep/dvab009

MLA

Schrott, Rose, et al. "Refraining from use diminishes cannabis-associated epigenetic changes in human sperm.." Environmental epigenetics, 2021. https://doi.org/10.1093/eep/dvab009

RethinkTHC

RethinkTHC Research Database. "Refraining from use diminishes cannabis-associated epigeneti..." RTHC-03503. Retrieved from https://rethinkthc.com/research/schrott-2021-refraining-from-use-diminishes

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.