Effects of Khat (Catha edulis) chewing on seminal fluid parameters: findings from a fertility clinic cohort and cessation trial.

Background: Khat (Catha edulis) chewing is a culturally ingrained practice in Yemen and has been associated with potential impairment of male reproductive function. However, rigorous quantitative assessments of its effects on seminal parameters are limited. This study investigates the relationship between khat consumption and semen characteristics and examines the reversibility of any adverse effects following cessation.  Methods: A prospective two-phase study was conducted at Dr. Najat Al-Malas IVF Center in Sana'a, Yemen (2019-2024). Phase 1 compared semen volume and related parameters across four age-, BMI-, education-, and socioeconomic-matched cohorts: infertile khat chewers (n=91), infertile non-chewers (n=60), fertile khat chewers (n=91), and fertile non-chewers (n=32). Phase 2 involved a three-month supervised khat cessation intervention among infertile chewers. Semen samples were obtained via standardized collection methods. Associations between khat use and seminal parameters were analyzed using univariate and multivariate regression models.  Results: Khat chewers demonstrated significantly reduced semen volumes compared to non-chewers in all comparisons. Infertile chewers had lower volumes (1.94±0.48 mL) than fertile chewers (2.36±0.52 mL; p<0.001, d=0.85) and infertile nonchewers (3.07±0.74 mL; p<0.001, d=1.72). Pooled analysis indicated that chewers (n=182) had 29.6% lower semen volumes than non-chewers (n=92) (2.15±0.89 mL vs. 3.04 ± 0.76 mL; p<0.001). Notably, cessation of khat chewing led to a 35% increase in volume among infertile chewers (from 1.94±0.48 mL to 2.62 ± 0.52 mL; p<0.001, d=1.21). Hormonal analysis (n=15) showed increased testosterone and decreased prolactin post-cessation (p<0.05).

Conclusions: Khat chewing is significantly associated with reduced semen volume and impaired seminal fluid parameters in men. Importantly, cessation of khat use leads to a marked improvement in semen volume and favorable hormonal changes, indicating partial reversibility of its adverse effects. These findings highlight khat's detrimental impact on male reproductive health and underscore the potential benefits of quitting khat for fertility restoration.