The study found that men with infertility had higher levels of kisspeptin in their blood compared to fertile men, while kisspeptin levels in semen didn’t differ much. This suggests blood kisspeptin could be a useful marker for spotting male infertility, but it doesn’t tell us how to treat it yet.

This study aimed to identify kisspeptin as a new marker for infertility in men with abnormal semen parameters by comparing serum and seminal plasma kisspeptin levels between fertile men and infertile men with normal and abnormal semen parameters. Fertile men (group A), infertile men with normal semen parameters (group B), and infertile men with abnormal semen parameters (group C) were recruited. Fasting venous blood was tested for kisspeptin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, insulin-like growth factor 1 (IGF-1), insulin, and glucose. Semen was collected by self-masturbation, and semen analysis was performed, then was tested for kisspeptin and testosterone. Fifty-two men were included in the study (17 fertile men in group A, 18 infertile men in group B, and 17 infertile men in group C). Serum kisspeptin levels were significantly lower in fertile men (group A) as compared to infertile men (groups B and C) regardless to semen parameters (85.18 ± 20.47 ng/dL, 109.37 ± 28.64 ng/dL, and 108.70 ± 32.30 ng/dL respectively; p = 0.019). While seminal plasma kisspeptin levels were not significantly different (245.95 ± 67.12 ng/dL, 283.73 ± 119.82 ng/dL, and 312.99 ± 245.17 ng/dL, respectively; p = 0.48). There was no significant difference among groups for serum FSH, LH, testosterone, IGF-1, fasting insulin, fasting glucose, homeostasis model assessment of insulin resistance (HOMA-IR), and seminal plasma testosterone. Serum kisspeptin might be used as a more sensitive marker for male infertility rather than FSH and LH. However, the clinical application of kisspeptin in the treatment of male infertility requires further study.