KnowHOW team explains: Not all naturally bald heads are shiny, and not all shiny heads are naturally bald, but all shiny heads have something in common: active sebaceous glands, little collections of cells emptying into hair follicles that produce a waxy or oily substance called sebum.

Other oil-producing skin cells may add to the shine. Sebum, the same substance that builds up to clog pores in teenage acne, may still ooze out of hair follicles that are no longer producing hair shafts.

Men, who suffer disproportionately from hair loss, may also produce more sebum than women with hair loss do, because the production is under the influence of male sex hormones, especially testosterone.

Age and sex hormones also influence the proportions of the waxy or oily substances that make up sebum, including glycerides, fatty acids, wax esters and cholesterol.

Other normally hairless areas of the body, like the palms of the hands and the soles of the feet, do not grow shiny, because they lack sebaceous glands.

To reduce the shine, some men swear by aloe vera, moist towelettes or talcum powder.

The question was sent by Anuradha Srivastava from Jamshedpur