In the control group, all patients will go a double-blind therapy of a three-months period of treatment with oral carnitine (2g daily). After this period, all patients will undergo conventional intacytoplasmic sperm injection (ICSI).

In the study group, all patients underwent a double-blind therapy of a six-month period of treatment with oral carnitine (2g daily) combined with modifiable lifestyle factors. Patients were requested to follow a healthy standard diet, avoid excessive heat exposure, avoid or minimize exposure to pollutants, and stop smoking, coffee, alcohol, and drugs uptake.After this period, all patients will undergo conventional ICSI.

All participants were subjected to the same three-month period treatment protocol, which included 1) antioxidant treatment with L-Carnitine (2g daily); 2) frequent ejaculation every 2 days; and 3) minimizing adverse lifestyle factors.