Related Experiment Video
Updated: May 21, 2026

Minimal Erythema Dose (MED) Testing
Published on: May 28, 2013
UV protection and sunscreens: what to tell patients
Paul C Jou1, Ron J Feldman, Kenneth J Tomecki
1School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
Abstract:
Ultraviolet (UV) radiation is the major environmental risk factor for nonmelanoma skin cancer and is a suspected risk factor for melanoma. Avoiding overexposure to direct sunlight during the peak daylight hours, wearing protective clothing, and applying sunscreen are ways to protect the skin. To provide clinicians with the tools to advise patients and to answer their inquiries, including which sunscreen to use, we review UV radiation's effect on the skin, how sunscreens block UV light, current recommendations on sunscreen use, and new sunscreen labeling requirements.
Related Concept Videos
Mutations
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
Personal Protective Equipment
Acne Infection
Transmission-based Precautions II: Airborne and Protective Environment
Airborne precautions:
Use airborne precautions when treating patients known or suspected to have diseases that spread through the air—for example, tuberculosis or measles. These organisms are present in smaller droplets expelled by an infected person and...
Pigmentation
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...
Role of Skin in Vitamin D Synthesis
The solar UV B rays (290-315 nm) are absorbed by the skin, and 7-dehydrocholesterol (provitamin D3) photolyzes it to previtamin D3, which undergoes a rapid transformation to vitamin D3(cholecalciferol).

