DHT production is increased. Another result of smoking is a rise in dihydrotestosterone (DHT), a kind of hormone3 that gives males their masculine characteristics, among other things. DHT is also thought to have a significant role in male and female hair loss by influencing the hair development cycle. Smoking has been shown to increase the rate of hair loss in men and women, probably due to higher levels of DHT. Smoking also appears to play a role in acne formation. Studies show that smokers have more severe cases of acne than non-smokers. It has been suggested that nicotine may be responsible for causing inflammation of the sebaceous glands, which produce oil that keeps your skin clean and moisturized. As an added side effect, smoking may cause hyperpigmentation and scarring. Darker skin colors are prone to absorbing more of the UV radiation from sunlight than lighter skins do, so they are at greater risk for developing skin cancers. Smoking can also lead to thicker skin, which may explain why so many heavy metal musicians have extremely flaky skin. Thicker skin is also useful for people who work with tools or chemicals because it allows them to keep going without getting too many injuries. Finally, there is some evidence that smoking may cause alopecia areata, which is a condition where the body's own immune system destroys hair follicles without warning or reason.