Heres the deal: All wrinkles form from a mix of the same factors. Neck wrinkles are caused by the same things that cause other wrinkles: a combination of aging of the skinbreakdown of collagen and elastic tissueand movement, says board-certified dermatologist Jeremy Fenton, M.D., of Schweiger Dermatology Group in NYC and Long Beach, NY. This is also especially true of the neck, as the skin here does tend to be thinner, and thinner skin is often impacted by aging faster (the same reason your eyes may show fine lines before any other part of your face.)

First up, collagen and elastin breakdown. As we age, our skin becomes less resilient with less of the collagen and elastic tissue to allow it to rebound to its original shape, he says. Besides this being a natural part of aging, it can happen faster with more exposure to sunlight (UV light). The neck can capture a lot of sun damage, particularly on the sides and lower portion.

Now combine aging skin with daily movements, and things start to settle in. The second main cause is the movement of the neck, says Fenton. We get horizontal lines in the neck due to the bending of the neck to look down. You can also get some of the more fine lines or wrinkles, particularly along the sides of the neck, from turning side-to-side and from sleeping on your side, but these dont tend to be the deep wrinkles.

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Here Is Everything You Need To Know About Tech Neck & Neck Wrinkles - mindbodygreen.com