Cannabis smoking impaired sperm quality and DNA integrity more than tobacco smoking | Research

The takeaway

Among 113 men, cannabis smokers had significantly more immotile sperm and greater DNA damage than both tobacco smokers and non-smokers, though mitochondrial gene variants did not differ between groups.

Reproductive medicine specialists, fertility counselors, men considering cannabis use

Cannabis smokers had significantly worse sperm DNA integrity than tobacco smokers

What the researchers found

Comparing 37 non-smokers, 39 tobacco smokers, and 37 cannabis smokers, both tobacco and cannabis groups showed reduced normal sperm morphology and non-progressive motility. However, cannabis smokers had significantly higher rates of immotile sperm, positive acridine orange staining (indicating DNA denaturation), and positive CMA3 scores (indicating chromatin immaturity) compared to both tobacco smokers and non-smokers (P<0.001). No differences in mitochondrial cytochrome C oxidase gene variants were found between groups.

Why it matters

As cannabis use increases among men of reproductive age while tobacco use declines, understanding the comparative reproductive risks matters. This study found cannabis smoking produced worse sperm DNA damage than tobacco, suggesting a distinct mechanism of reproductive harm.

The numbers in context

n=113 (37 NS, 39 TS, 37 CS); cannabis smokers had higher immotile sperm, AO+, and CMA3+ scores (all P<0.001 vs NS and TS); 23 SNPs in MT-CO1, 15 in MT-CO2, 30 in MT-CO3, none different between groups

How the study worked

Semen samples from 113 men divided into non-smokers (n=37), tobacco smokers (n=39), and cannabis smokers (n=37). Sperm quality assessed by standard parameters. DNA integrity tested by Chromomycin A3 and acridine orange staining. Mitochondrial MT-CO1, MT-CO2, and MT-CO3 genes amplified and sequenced.

What this study cannot tell us

Small sample sizes per group (37-39). Cross-sectional design cannot establish causation. Did not control for frequency or duration of smoking. Co-use of cannabis and tobacco was not addressed. Genetic analysis was limited to mitochondrial genes.

How to read the evidence

Small cross-sectional study with three comparison groups provides preliminary evidence, but limited sample sizes and inability to control for co-use patterns reduce confidence.

When this study was published

2025 publication

The bigger picture

Male fertility has been declining globally, and understanding modifiable risk factors is critical. This study adds cannabis smoking to the list of reproductive hazards and suggests it may be more damaging to sperm DNA than tobacco, a finding relevant to fertility counseling.

Questions still open

Does cannabis-related sperm damage reverse with cessation? Is the damage driven by THC, combustion products, or both?

Common questions

Is cannabis worse for sperm than tobacco?

In this study, cannabis smokers had significantly more immotile sperm and greater DNA damage than tobacco smokers. Both groups had worse outcomes than non-smokers, but cannabis showed a larger effect on DNA integrity markers.

Did the study find genetic changes from cannabis use?

No. While the study sequenced mitochondrial genes involved in sperm energy production, no genetic variants differed between cannabis smokers, tobacco smokers, and non-smokers, suggesting the sperm damage occurs through other mechanisms.

Read the original research

Effects of marijuana and tobacco on male fertility and their relationship to genetic variation of mitochondrial cytochrome C oxidase genes.

Scientific reports, 15(1), 7547

View on PubMed ↗Publisher’s paper ↗

Citation

Amor, Houda; Ismaeil, Ayham; Jankowski, Peter Michael; Smadi, Mohammad A Al; Zoubi, Mazhar S Al; Juhasz-Böss, Ingolf; Hammadeh, Mohamad Eid. (2025). Effects of marijuana and tobacco on male fertility and their relationship to genetic variation of mitochondrial cytochrome C oxidase genes.. Scientific reports, 15(1), 7547. https://doi.org/10.1038/s41598-025-91894-0