How long after quitting weed does male fertility improve?

What does the evidence say about quitting weed before trying to conceive while trying to conceive?

1. Women who used cannabis around the time they were trying to conceive were about 40% less likely to get pregnant in a given monthly cycle than women who did not use it, in an NIH-funded study that followed more than 1,200 women trying to conceive. 1
2. Evidence on cannabis and male fertility is genuinely mixed: some studies tie chronic use to lower testosterone and luteinizing hormone along with weaker semen parameters, while others find no clear hormone effect, and cannabis use has also been linked to altered DNA methylation patterns in sperm. 2
3. In a direct comparison of 113 men, current cannabis smokers had significantly lower rates of normal sperm shape and far more immotile, DNA-damaged sperm than both tobacco smokers and non-smokers, though total sperm concentration did not differ significantly between the groups. 3
4. After 77 days of cannabis abstinence, about the length of one full sperm production cycle of roughly 74 days, researchers found that most of the sperm DNA changes linked to cannabis use were markedly reduced, though only partly, not completely, resolved. 4
5. In laboratory research, eggs exposed to THC at concentrations similar to recreational use reached the maturity needed for fertilization far less often than unexposed eggs, and the embryos that did form showed more cell death, pointing to a possible route by which cannabis could affect egg quality. 5

What to know about quitting weed before trying to conceive while trying to conceive

• If you or your partner currently use cannabis and pregnancy is somewhere on the horizon, this is the point to set a quit date rather than stopping the same week you start trying. Sperm being formed today will not be fully mature for roughly two and a half months, so quitting earlier gives more of that supply time to develop without cannabis exposure.
• The stretch after quitting and before actively trying is when sperm quality has the most room to improve, since one full sperm production cycle runs about 74 days. Research on men who stopped cannabis for 77 days found that most, though not all, cannabis-linked changes to sperm were no longer detectable by the end of that window.
• Once you are actively trying or have a positive test, quitting cannabis still matters for both partners: separate research found women who used cannabis around the time of conception were about 40% less likely to get pregnant in a given cycle than women who did not. If quitting did not happen earlier, stopping now is still worthwhile, even though sperm changes may take longer to fully resolve at that point.