At what age does perimenopause usually begin?

Most women enter perimenopause in their mid to late 40s. As the average age of natural menopause is around 51, the transition usually begins around the mid-40s and lasts between two and ten years. Differences from woman to woman are large. It is important to know that hormonal changes can be under way long before your cycle becomes irregular or stops. That is why you should take symptoms seriously even in your late 30s or early 40s.