Sunscreen ingredients and effectiveness vary widely. Most people don’t think about the sunscreen that they choose beyond the SPF on the bottle and maybe the price. Were you aware that the SPF has nothing to do with protection against skin cancer? There are a lot more factors to consider.
The two major categories of sunscreen on the market are chemical-based and mineral-based. Chemical-based sunscreens use chemicals which have ultra violet (UV) ray blocking ability. Chemical-based sunscreens make up the majority of sunscreens on the market (around 70%). Mineral-based sunscreens use minerals such as zinc oxide and titanium dioxide to block UV rays and are generally thought to be safer.
There are two main types of UV light that is transmitted through the atmosphere from the Sun, UVB and UVA. UVB is what SPF rating is based on. It is the part of UV light that causes sunburn. UVA light penetrates deeper into the skin and harder to block with sunscreen. It is the part of UV light that causes skin cancer. Most sunscreens will block a certain amount of both UVA and UVB light. Chemical-based sunscreen, especially those with high SPF, are less effective at blocking UVA light than mineral-based sunscreen. Many of the chemicals used, most notably oxybenzone, have been shown to have negative health effects, such as increasing cancer risk, hormone-disruption, skin irritation, and allergy. Zinc oxide is considered to be the best sunscreen because it blocks both UVB and UVA light effectively. Mineral-based sunscreen use has been on the rise because of the balance of UVB and UVA protection and general safety. The consumer advocacy group Environmental Working Group (EWG.org/sunscreen) rates sunscreens every year based upon their health hazards, protection, and stability.
Spray sunscreen, although popular, may not provide an even coating on the skin and has inhalation risks. The FDA is considering banning this type of sunscreen unless companies can provide more information about effectiveness and safety hazards.
Nanoparticles in sunscreen are either zinc oxide or titanium dioxide. Nano refers to the small size of the molecule. Nano particles may provide higher SPF, but less UVA blocking. The reason that these smaller molecules are used is that it makes the mineral sunscreen more transparent and less chalky. Many sunscreens tout their product as being “non-nano”, but this is misleading because most would qualify as a nanomaterial by European standards. The other concern about nanoparticles is about absorbability into the body. Studies have shown that nanoparticles in sunscreen do not penetrate the skin in any significant amount. However, they may cause damage if inhaled, so use of loose powder or spray sunscreens is not recommended. Overall the EWG considers Zinc Oxide to be the safest and most effective sunscreen available wqy90b1.
People are more likely to use high SPF products improperly, which may result in more exposure to ultraviolet radiation. For example, someone may rely on the high SPF to protect them longer in the sun and therefore not reapply as often. High SPF products may also mislead consumers because they don’t really provide a significant increase in sunburn protection over a lower SPF. For example, SPF 50, when properly applied blocks 98% of sunburn-causing rays, but SPF 100 only blocks 99%, which is a negligible increase. High SPF products may provide less protection from the more damaging UVA rays which penetrate deeper and are a cause of melanoma.
Don’t block out all of the rays in order to receive the benefit of vitamin D from the Sun. The body makes active vitamin D from UVB rays. It would generally take 15 minutes of full body exposure between 11 AM and 2 PM to get a full day’s worth of vitamin D. I usually recommend going out before 11 AM or after 2 PM without sunscreen (unless at the beach or a pool or if you burn easily). I also recommend protecting the delicate skin of the face at all times.
Dr. Stacey Munro is a Naturopathic physician who specializes in the treatment of chronic health conditions. Naturopathic medicine treatment supports the innate self-healing ability of the body, also known as the Vis Medicatrix Naturae or the Healing Power of Nature. Dr. Munro prescribes dietary and lifestyle changes, nutritional supplements, herbal medicine, and other therapies as prevention and treatment for disease. Following Naturopathic philosophy, she looks for the root cause, rather than just treating symptoms.