How Does Our Skin Protect Us?

Sunlight is such a double-edged sword, isn’t it? Our skin works remarkably hard to protect and defend against harmful UV rays, but the bad news is our skin’s defenses alone are not enough.

Emilia Javorsky
Jan 18, 2018 · 4 min read

What Happens When Our Skin Is Exposed To UV Radiation?

Our skin defenses respond to UV light in two main ways: first, building up its shield so less damaging light gets into the skin and second, mobilizing a first-aid system to repair UV-damage from light rays that get past the shield.

Our First Response: Melanin

Cue the first line of defense. The objective — block harmful light from penetrating the skin. Skin produces a pigment, called melanin, to absorb UV energy and divert it away from healthy cells. Skin cells first deploy melanin they have on hand and then go into melanin production to get more pigment to the skin.

Our Second Response: Thickening

The second way our skin builds up its shield in response to sun is increasing thickness of the outermost layer of skin (called the stratum corneum), composed mainly of dead skin cells.

Our Third Responses: DNA Repair

But alas, some UV light gets through despite our melanin production and thicker outer skin layer protection. UVB light causes direct damage to skin DNA, and UVA light generates “free radicals”, largely from oxygen, that damage DNA and proteins. It’s time to call in skin’s third and fourth responses — chemical repair teams to deal with the damage.

Our Fourth Responses: Antioxidants

While cells are attempting to repair DNA, they also release another repair team — the antioxidants. You’ve probably heard of antioxidants related to colorful foods like pomegranate and green tea. There are many types of antioxidants in our skin, all combating “oxidative” damage by free radicals.

What If That’s Not Enough?

If sun exposure is too high or protection too weak, despite our skin’s best efforts, sometimes damage is irreversible. If a cell is very badly damaged, the cell activates a program called apoptosis, or programmed cell death.

An Incredible System, But It Still Needs Help

In summary, millions of years of biological trial and error have given us a remarkable system in our skin that fights sun damage in multiple ways. But that system far from 100% effective.

  1. Pisoschi AM, Pop A. The role of antioxidants in the chemistry of oxidative stress: A review. Eur J Med Chem. 2015;(97) 55–74
  2. Rinnerthaler M, et al. Oxidative stress in aging human skin. Biomolecules. 2015; 5(2)545–89

Sundots: Living In The Sun

Sundots provide sun protection in a daily gummy.

Emilia Javorsky

Written by

Physician-Scientist, Cofounder&CSO Sundots, AI&Health@ The Future Society, Forbes 30 Under 30- Healthcare, former MGH/HMS researcher

Sundots: Living In The Sun

Sundots provide sun protection in a daily gummy.