Retin-A is one of the brand names of tretinoin, a type of retinoid only available by prescription, as opposed to the similar but gentler, over-the-counter retinols. Retin-A and other retinoids are backed by 25 years of research and proven to improve skin issues, including acne and problems associated with aging and sun damage, such as wrinkling and discoloration. Since Retin-A is working to undo damage caused by the sun, it makes sense that dermatologists recommend protecting skin treated with retinoids from the sun to help maintain results, as well as preventing undesirable effects.
Retinoids, as well as retinols, are photo-inactivated, meaning exposure to direct sunlight makes them less effective. For this reason, they are normally prescribed to be used at night, right before going to bed. UVA, or long-wave rays found in the sun and the primary ray used in tanning booths, break down this active ingredient the most and are able to penetrate glass. The sun's UVB shortwaves also degrades tretinoin, as does as any visible light. If your Retin-A is less effective, you won't get the full benefits of this highly effective treatment and may be prone to stop using it. Since retinoids work best over a long period of time, you should wear sunscreen and look forward to better skin.
Because Retin-A helps replace older skin with fresh, new cells, skin treated with this cream is more prone to sunburn, especially in the first several weeks of use. Retin-A should not be applied to skin that is sunburned or windburned, so you'll lose valuable treatment time, waiting until your skin is healthy enough to restart your skincare regimen if you experience a burn. Some animal studies have shown that tretinoin caused skin tumors to develop faster when the treated area was exposed to UV light from the sun or sunlamps.
Exposing unprotected skin to excessive UV radiation not only gives you sunburn, but can cause changes in skin cells that lead to skin cancer. Sunburns may also increase your chances of developing melanoma, the most serious form of skin cancer, later in life. Because using Retin-A puts you at a higher risk for sunburn, you also run the risk of developing non-melanoma skin cancers, such as basal cell carcinoma and squamous cell carcinoma tumors, which develop most commonly in sun-exposed areas, such as the face and ears.
To stay safe and get the best results from Retin-A, wear sunscreen daily with an SPF of 15 or higher that protects you from both UVA and UVB rays with labels using phrasing like broad-spectrum, multi-spectrum, zinc oxide and UVA/UVB protection. If you're planning a day outdoors, use a water-resistant, broad-spectrum sunscreen with an SPF of 30 or higher. Apply a generous amount of sunscreen 30 minutes before going out and reapply every two hours and excessive sweating or swimming. See your doctor every year for a professional skin exam.