L – arginine là ti?n ch?t c?a oxit nitric, m?t ch?t làm giãn m?ch máu. Vi?c t?ng c??ng s?n xu?t oxit nitric giúp c?i thi?n l?u thông máu ??n c? quan sinh d?c, t? ?ó c?i thi?n kh? n?ng c??ng d??ng ? nam gi?i.The flagellar system, having said that, seems to become a lot more complicated than the muscle program, mainly because it does not �