Estradiol levels change significantly with age, particularly in women. During the reproductive years, estradiol levels fluctuate throughout the menstrual cycle, with higher levels during the follicular phase (before ovulation) and lower levels during the luteal phase (after ovulation). As women approach perimenopause and menopause, estradiol levels decline, leading to the cessation of menstruation and various menopausal symptoms. In men, estradiol levels tend to remain relatively stable throughout adulthood, with a gradual decline in later years. These age-related changes in estradiol levels can impact reproductive health, bone health, and overall well-being, highlighting the importance of monitoring and managing hormone levels as people age.