Most sun exposure occurs before the age of 18. During that time, much of the damage has already been done and is hiding in the deep levels of the skin. As adults, most people continue to over expose their skin to the damaging rays of the sun, furthering the damage.
No matter the level of photoaging (aging of the skin due to sun exposure) your skin has, it is never too late to start protecting against further damage.
Make sure you are using a sunscreen with an SPF of at least 15 everyday. Sunscreen should be applied 15 minutes before going in the sun. And, if you are swimming or exercising, make sure to apply sunscreen more often.
Recent studies have shown that people over fifty years of age, can reduce the number of precancerous lesions they have simply by applying sunscreen each day.
In some cases, a Dermatologist can also prescribe 5-fluorouracil treatments which are effective in reducing precancerous changes in skin cells. An added benefit to this treatment is that it rejuvenates skin making it appear smoother and younger.
The most common treatment for reversing sun damage is to use a vitamin A acid derivative, like retinoic acid or adapalene. These are available in prescribed creams and gels such as Retin-A, Renova, Tazorac, and Differin. There are also some over-the-counter treatments that contain retinol. Treatment can diminish damage such as fine lines and changes to the pigment (sun spots). Glycolic acid is another chemical product that has shown promising results in reversing sun damage.
Today, there are also many vitamins and herbs that are marketed to people who are looking to reverse sun damage. Antioxidants like vitamin C, berry extracts, green tea, coenzyme Q, growth factors, and peptides have all been shown to help reverse skin damage and rejuvenate the skin. Commercial products are somewhat effective but you will need to see a dermatologist to get prescription for a higher concentration.