Quitting Cannabis Reverses DNA Changes in Sperm | Research

The takeaway

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

Reproductive health researchers, men planning to conceive, epigeneticists

77 days of cannabis abstinence significantly reduced sperm DNA methylation changes at developmental genes

What the researchers 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.

Why it 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 numbers in context

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 the study worked

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.

What this study cannot 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.

How to read the evidence

Small prospective study using advanced genomic methods provides preliminary evidence for reversibility of epigenetic changes.

When this study was published

Published in 2021.

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.

Questions still open

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?

Common 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 the original research

Refraining from use diminishes cannabis-associated epigenetic changes in human sperm.

Environmental epigenetics, 7(1), dvab009

View on PubMed ↗Publisher’s paper ↗

Citation

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