Question:

What difference is there (if any) between sun block, sunscreen, and sun tan lotion? Does one block sun completely while another helps in tanning? How do lotion companies decide how to classify them?

Answer:

There are many types of “sun lotions” on the market today and your question highlights the variety. First, the term “sun tan lotion” can mean anything having to do with the sun. Generally, the term refers to a lotion used when going out in the sun. The lotions that help provide a tanned appearance without the sun are called self-tanning lotions. The term “sun block” refers to ingredients which actually prevent the ultraviolet rays from the sun from penetrating through the upper layers and damaging the cells below. The sun block scatters the rays and scatter them back, thus preventing penetration. Titanium dioxide is a sunblock typically used. The term “sunscreen” refers to ingredients which do not prevent penetration but which prevent the penetrated rays from damaging the living cells below the surface layers. The most effective materials are the sun blocks. Also remember that exposure to the sun causes damage to the skin. The “tan” is the skin`s response to the ultraviolet light in that the pigment cells transfer pigment to protect the living cells. However, damage still occurs.

For more information:

Go to the Skin Care and Diseases health topic.