Sperm Quality Declines With Storage Time, New Analysis Reveals
A comprehensive analysis of existing research, spanning from insects to mammals, including humans, has revealed that sperm quality declines the longer it is stored in the body. The study, published in the journal Proceedings of the Royal Society B, suggests that frequent ejaculation—through sexual intercourse or masturbation—may lead to the production of higher-quality sperm with less DNA damage. doi.org/10.1098/rspb.2025.3181
Meta-Analysis Reveals Key Findings
Researchers at Oxford University utilized meta-analysis, a statistical technique that combines the results of multiple studies, to draw conclusions based on a larger dataset than any single study could provide. The analysis included 115 human studies involving 54,889 men and 56 studies involving 30 animal species. Researchers analyzed variables including storage period, differences between male and female sperm storage, and study design.
Sperm Senescence: A Natural Decline
The quality of stored sperm decreases over time, regardless of a man’s age, a phenomenon known as ‘post-meiotic sperm senescence.’ In humans, longer periods of abstinence are associated with increased DNA damage to sperm, reduced motility, and lower survival rates.
“Because sperm are small and constantly moving, they quickly utilize up their stored energy,” explained Dr. Rebecca Dean. “They lack the ability to repair damage on their own, so the longer they are stored, the faster their condition deteriorates than other cells.”
Female Sperm Storage More Efficient
The study also found that females are able to maintain sperm quality for a longer period than males. This is attributed to the evolution of a specialized storage organ that secretes antioxidant substances.
“Females are able to keep sperm healthy longer thanks to the evolution of a special storage organ that secretes antioxidant substances. If we imitate the principles of this organ, we can use it to improve artificial sperm storage technology,” said Dr. Irem Sepil.
Dr. Krishi Sanghvi explained, “Ejaculate is a group of sperm in which sperm are born, grow old, and die. Since the speed of this process is different in males and females, the sperm storage effect also varies depending on gender.”
Implications for Fertility Treatment and Conservation
Current World Health Organization (WHO) guidelines recommend abstinence for 2 to 7 days before semen collection or assisted reproductive procedures. Though, the findings of this analysis suggest that longer abstinence periods may be detrimental to sperm quality, prompting a need to re-evaluate these recommendations. Recent research indicates that in vitro fertilization (IVF) success rates are significantly higher when ejaculation occurs within 48 hours of collection.
The research team believes their findings could improve guidelines for infertility clinics and endangered species breeding programs, as well as enhance our understanding of the evolutionary mechanisms that minimize sperm damage.