What does dimethicone do in sunscreen lotion?

What does dimethicone do?

Dimethicone forms a thin, nongreasy layer on the skin. It acts as an emollient, meaning it softens and smooths the outer skin layer, and as a barrier ingredient. That makes it useful in a lotion intended to moisturize as well as protect from the sun. Dimethicone is insoluble in water, but its film allows water vapor through. A silicone layer does not prevent skin breathability.13

Does dimethicone increase SPF?

A sunscreen's active ingredients protect against ultraviolet radiation, or UV. Other ingredients help make the finished formula. Film forming ingredients can influence how evenly UV filters are distributed and how well that distribution survives friction or perspiration. Specific combinations of silicone polymers and a powder called vinyl dimethicone/methicone silsesquioxane crosspolymer have improved protection in experimental sunscreen formulas. That compound is different from plain dimethicone, so seeing dimethicone on a bottle does not tell you its SPF or water resistance. Use the protection ratings on the finished product.24

Is it suitable for oily or sensitive skin?

Dimethicone is considered noncomedogenic, meaning it does not tend to clog pores, and has a low potential to cause allergy. Its nongreasy feel makes it useful in moisturizers for oily skin. Those ingredient properties do not make every sunscreen containing it suitable for acne prone or sensitive skin: some occlusive formulas can aggravate acne, and fragrances, preservatives or other components can cause contact allergy. The full formula matters more than one familiar name, even when the rest of the ingredient list reads like an equipment inventory.15

What should you look for on the bottle?

Choose SPF 30 or higher, broad spectrum protection against both UVA and UVB, and water resistance. A smooth finish is a texture benefit, not an extra protection rating, however persuasive the glide feels. For sensitive skin, dermatologists recommend mineral sunscreens with zinc oxide, titanium dioxide or both as active ingredients. Dimethicone does not determine whether a sunscreen is mineral, chemical or hybrid; the UV filters do. Water resistance must be tested, and no sunscreen is waterproof.26

How do you apply sunscreen lotion with dimethicone?

1. 1Read the lotion's directions, then apply sunscreen 15 minutes before sun exposure.
2. 2Cover all skin not covered by clothing evenly, avoiding the eyes and mouth. An average sized adult or child needs at least one ounce for coverage from head to toe.
3. 3Include easily missed areas such as the ears, back of the neck, hands, tops of the feet and hairline.
4. 4Reapply at least every two hours outdoors and after toweling off. During swimming or sweating, follow the label's water resistance interval of 40 or 80 minutes.

When should you stop using the lotion?

Stop using the lotion if contact dermatitis develops, meaning an inflamed skin reaction to something touching the skin. For a suspected allergy, a clinician can investigate ingredients such as fragrances or preservatives with patch testing. Do not assume dimethicone caused the reaction simply because it is on the label.3