Chinese scientists develop balm to boost sperm quality

Chinese scientists say they have developed a topical balm for the testes that could improve sperm activity and help address declining male fertility, a growing global health concern reports scmp.com.

Researchers from several institutions, including Fudan University’s Institute of Reproduction and Development and the Third Military Medical University in Chongqing, reported that the externally applied lotion significantly enhanced sperm quality in animal experiments and laboratory tests. The findings were published online on November 27 in the peer-reviewed journal The Innovation.

According to the research team, the treatment improved sperm motility regardless of the cause of decline, including exposure to heavy metals, plasticisers, heat stress, or natural ageing. Declining sperm quality — marked by low sperm count, abnormal shape and reduced movement — is a major contributor to male infertility, yet effective targeted treatments remain limited.

Globally, about one in six people of reproductive age experience infertility at some point in their lives, according to the World Health Organization. Male infertility is most often linked to low sperm count, poor sperm motility or problems with semen ejaculation.

China has seen similar trends. Data from a major sperm bank in Hunan province showed donor sperm pass rates dropped from nearly 46 per cent in 2006 to about 20 per cent in recent years, reflecting the national average. Researchers attribute the decline to factors such as environmental pollution, unhealthy lifestyles and work-related stress.

The new treatment uses extracellular vesicles derived from milk — nanoscale carriers that transport biological signals — loaded with a protein called SKAP2, which specifically binds to mature sperm cells. These vesicles are embedded in a hydrogel that can be applied directly to the scrotal skin.

After one month of topical application in mice, researchers observed significant improvements in sperm motility. In mice exposed to lead, forward sperm motility increased from 12.3 per cent to 23.3 per cent. The balm also reversed motility damage caused by heat exposure and plastic chemicals such as dibutyl phthalate (DBP), with some models showing more than a twofold increase in sperm vitality.

The team also conducted laboratory tests using semen samples from 16 men diagnosed with low sperm motility in three Chinese cities. When co-cultured with the hydrogel, the samples showed significantly improved forward movement and overall vitality compared with untreated controls.

The technology has been patented, and researchers say they are working to translate the findings into a commercial product. The authors described the balm as “the first targeted repair strategy” aimed at improving reduced sperm motility in clinical practice.

Medical experts have previously warned that declining sperm count and motility worldwide are linked to rising infertility rates. A national reproductive health survey in China found infertility increased from 12 per cent in 2007 to 18 per cent in 2020, meaning roughly one in every 5.6 couples of childbearing age now faces difficulty conceiving.

Researchers note that infertility is influenced by multiple factors, including ageing, environmental exposure, genetic abnormalities and lifestyle choices.