Sperm quality deteriorates rapidly during storage-even in healthy men-according to a University of Oxford study. Researchers analyzed 115 human studies involving nearly 55,000 men and found that prolonged sexual abstinence increases DNA damage, oxidative stress, and reduces motility.
"Because sperm are highly mobile and have minimal cytoplasm, they quickly exhaust energy reserves and can’t repair themselves," said Dr. Rebecca Dean, co-lead author from Oxford’s Department of Biology.
The team also compared sperm storage across 30 non-human species and discovered females generally preserve sperm better than males, likely due to specialized reproductive organs that secrete antioxidants and nourishing fluids.
Current World Health Organization guidelines allow up to seven days of abstinence before semen analysis-but the new data suggest samples provided after just 48 hours may yield significantly better results for IVF success.
"Ejaculates should be viewed as populations of individual sperm undergoing birth, death, and ageing," explained lead author Dr. Krish Sanghvi. "Regular ejaculation flushes out older, damaged sperm."
The findings could reshape clinical fertility protocols and inform conservation breeding programs.