You’re heading out for a nice day by the water and, as an afterthought, realize you might need some sunscreen. (That tube you have from years past is definitely expired!) So, you stop by the store and grab whichever sunscreen is on display or on sale. But what should you be looking for on those labels, marketing tactics aside?
Ultraviolet (UV) radiation is made up of three wavelengths – UVA, UVB and UVC – and is the main cause of skin cancers, including basal cell carcinoma and squamous cell carcinoma. UVC isn’t a concern for skin cancer, but UVA and UVB both play a role in its development.
UVA, while not as intense as UVB, penetrates the skin deeper and is thought to be a major contributor to skin aging and wrinkling. UVA can also penetrate glass and clouds and is present during all daylight hours. New research suggests that UVA may be as damaging to the skin as UVB.
UVB causes more superficial damage to the outer layers of the dermis but is still thought to play a major role in the development of skin cancer. UVB intensity varies by season, location and time of day, with the most dangerous exposure between April and October, from 10 a.m. to 2 p.m.
Fortunately, you can shield your skin from UV radiation with the right ingredients. Next time you walk down the sunscreen aisle, know what to look for on those labels to avoid long- and short-term skin damage.
FDA-approved active ingredients
Effective UVA/UVB coverage requires an SPF of 30 or higher and some combination of UVA/UVB absorbers/blockers.
[checklist]- UVB absorbers/blockers: Padimate O (Octyl dimethyl PABA), Homosalate, Octisalate (Octyl salicylate), Octinoxate (Octyl methoxycinnamate or OCM)
- UVA absorbers/blockers: Avobenzone (Parsol 1789), Ecamsule (Mexoryl) and Zinc Oxide
- UVA and UVB absorbers/blockers: Octocrylene, Titanium Dioxide, Zinc Oxide
Multi spectrum, broad spectrum or UVA/UVB protection
These labels indicate that some UVA protection is provided, however, there is no general consensus on how much protection is actually being delivered. Make sure you check the sunscreen’s ingredient list against the UVA/UVB absorbers and blockers above as these labels may be misleading.
Water resistance
The FDA ensures that any product labeled “water resistant” provides at least 40 minutes of swimming or sweating protection. However, experts claim that no sunscreen is 100 percent waterproof, so make sure you’re reapplying every 30 minutes to be safe.
Sun Protection Factor (SPF)
The SPF indicates your relative protection from erythema, or redness of the skin, caused by UVB. It does not, however, indicate the level of protection from UVA. To get adequate protection from both, buy a sunscreen with an SPF of at least 30 that contains UVA blockers such as Avobenzone, Ecamsule and Zinc Oxide.
If you’re using sunscreen on a regular basis, it should never go bad. Each application should be about 1 ounce – the amount in a shot glass – to protect all exposed parts of the body. (If you have a four-ounce bottle, that’s only four uses!) As a rule, throw out sunscreen that is more three years old, is past its expiration date or that has been exposed to high temperatures.
Sources
http://www.skincancer.org/prevention/uva-and-uvb/shining-light-on-ultraviolet-radiation
http://www.geteyesmart.org/eyesmart/living/sun.cfm
http://www.mayoclinic.com/health/sunscreen-expire/AN01968
This material is provided for informational use only and should not be construed as medical advice or used in place of consulting a licensed medical professional. You should consult with your doctor.