Skin laxity occurs as a result of lost skin elasticity. Your skin’s elasticity enables it to bounce back from stretching, hold a taut form to your body and resist the effects of gravity. Skin laxity varies from individual to individual with some naturally possessing more elastic skin than others.
Healthy, youthful, and vibrant skin is something we’re each born with naturally, but as time passes, a variety of factors degrade the quality of the skin. One of these issues is the loss of collagen and elastin in the skin, which leads to loss of skin elasticity.
Cited from the Mayo Clinic & the American Academy of Dermatology