Human Hair (Single Strand)

A cylinder of dead keratin you obsess over daily/Medicine & Biology

A single strand of human hair is about 70 micrometers in diameter, which is roughly the width of the thinnest sewing needle. Hair grows at about 1.25 cm per month, or roughly 15 cm per year. A single strand can support about 100 grams of weight. Your head has about 100,000 hairs, giving your scalp a combined tensile strength capable of supporting two elephants.