Differences in male and female pattern hair loss based on androgens, estrogen, iron, vitamin D, lipid metabolism, and genetic regulation

Male hair loss has all the signs of androgenic effects and miniaturization. Female hair loss has thinning, shedding, and slow growth but rarely progresses to complete baldness unless associated with inflammation or scarring alopecia’s, which may be explained by the influence of female hormones and unique attributes of female metabolism. The hairline is preserved in females due to the enzyme aromatase which converts testosterone to estradiol. Females are prone to autoimmune disorders, chronic pain, anxiety, and depression whereas males are prone to infectious diseases, aggressive behavior, hypertension, cardiovascular disorders, and drug abuse. Estradiol and prolactin affect hair growth. Estradiol attenuates cortisol altering the physiological response to stress. Estradiol is proinflammatory. There are significant differences in steroid biosynthesis, estrogen, and arachidonic acid pathways in females. Female hormone cycles mask the androgenic effects and prevent the development of characteristic clinical signs of androgenetic alopecia. Metabolism of Vitamin D, iron, lipids, glucose, and fatty acids differs in females. Genome-wide association study has identified unique genetic loci that influence hair loss in females. Female pattern hair loss can develop in the absence of androgens. Male and female hair loss patterns have subtle variations and may appear across gender barriers. Understanding the differences between male and female pattern hair loss would be a pragmatic aid in clinical management.