What is a MED?
Minimum Erythemal Dose (MED) is the amount of sunlight exposure necessary to induce a barely perceptible redness of the skin within 24 hours after sun exposure. In other words, exposure to 1 MED results in a reddening of the skin. You can determine the number of minutes of sun exposure it takes to burn by dividing 60 by the MEDs per hour. We use the term “skin factor” to describe how different skin types burn at different rates.
