To help you stay sun-safe, Oregon Medical Group Internal Medicine physician, Marisa Simon, MD, MPH, is sharing sunscreen tips based on guidance from the American Academy of Dermatology.
Why wear sunscreen?
Wearing sunscreen is one of the best ways to protect your skin. Studies show it can lower your risk of skin cancer and sun damage. For example, in places like Australia with very strong sun, people who used sunscreen every day over 10 years reduced the incidence of skin cancer by about 70% [2] than those who used it only sometimes. Skin cancer, especially melanoma, can be life threatening if it spreads, so protection really matters.
What dermatologists recommend for being out in the sun
- Use a broad spectrum SPF 30 or higher on all uncovered skin
- Reapply every 2 hours, or after swimming or sweating
- Use about 1 ounce (the amount of a shot glass) for your whole body
- Add extra protection with sun protective clothing, a wide brimmed hat, UV blocking sunglasses, and find shade during peak hours between 10 a.m. and 2 p.m.
Are all sunscreen ingredients safe?
Currently, research shows that mineral sunscreens with zinc oxide or titanium dioxide are the safest to use. They sit on top of the skin, are not absorbed into the bloodstream, and have not been linked to causing cancer or hormone problems.
Spray versions of mineral sunscreen are not recommended because breathing in the particles may cause lung irritation or damage.
Some chemical sunscreen ingredients don’t have enough safety data yet. They are still considered better than using no sunscreen at all, but mineral options are preferred when available. Chemicals that aren’t safe include PABA and trolamine salicylate, so check the label before you buy.
When does sunscreen expire?
Most sunscreen lasts up to 3 years if unopened. Once opened, it’s best to use it within 6–12 months.
Does sunscreen block vitamin D?
Yes. Sunscreen blocks UVB rays, which help your body produce vitamin D. Vitamin D is necessary for calcium regulation, bone and muscle health, and maybe even mood. It is important to take a daily vitamin D supplement if your provider has told you it is safe. This is especially important if you live in a northern state where the sun isn’t as strong, during winter, or if you have a darker skin tone which blocks UVB rays.
How to watch for skin cancer
Talk with your primary care doctor or dermatologist if you have higher risk factors like:
- Fair skin tone
- A history of blistering sunburns or tanning bed use
- Many moles or freckles of different shapes and sizes
- A personal or family history of melanoma
- A weakened immune system
For any new or changing spot, ask your doctor to take a look and use the ABCDE guide:
- Asymmetry: the spot isn’t even on both sides
- Border irregularity: edges aren’t smooth
- Color: more than one color in the same spot
- Diameter: larger than 6 mm (about the size of a pencil eraser)
- Evolving: changing quickly in size, or itching or bleeding
If you ever notice something concerning, reach out to your primary care provider or a dermatologist for guidance.
Staying sun safe is one of the easiest ways to protect your health, and your care team at Oregon Medical Group is here to help you keep your skin healthy and happy.
References
1. Position Statement: Broad-Spectrum Protection of Sunscreen Products. American Academy of Dermatology (2022).
2. Cutaneous Melanoma. Joshi UM, Kashani-Sabet M, Kirkwood JM. JAMA. 2025;334(23):2113-2125. doi:10.1001/jama.2025.13074.
3. Effect of Sunscreen Application Under Maximal Use Conditions on Plasma Concentration of Sunscreen Active Ingredients: A Randomized Clinical Trial. Matta MK, Zusterzeel R, Pilli NR, et al. JAMA. 2019;321(21):2082-2091. doi:10.1001/jama.2019.5586.
4. Sun Exposure in Travelers. David Fivenson and Scott A. Norton. CDC Yellow Book.
5. Mode of Action Approach Supports a Lack of Carcinogenic Potential of Six Organic UV Filters. Cohen SM, Boobis AR, Jacobson-Kram D, et al. Critical Reviews in Toxicology. 2025;55(2):248-284. doi:10.1080/10408444.2025.2462642.
6. Behavioral Counseling to Prevent Skin Cancer: US Preventive Services Task Force Recommendation Statement. US Preventive Services Task Force, Grossman DC, Curry SJ, et al. JAMA. 2018;319(11):1134-1142. doi:10.1001/jama.2018.1623.
7. 2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Arnett DK, Blumenthal RS, Albert MA, et al. Journal of the American College of Cardiology. 2019;74(10):e177-e232. doi:10.1016/j.jacc.2019.03.010.
8. Major Global Coronary Artery Calcium Guidelines. Golub IS, Termeie OG, Kristo S, et al. JACC. Cardiovascular Imaging. 2023;16(1):98-117. doi:10.1016/j.jcmg.2022.06.018.
9. Lipid Management for the Prevention of Atherosclerotic Cardiovascular Disease. Michos ED, McEvoy JW, Blumenthal RS. The New England Journal of Medicine. 2019;381(16):1557-1567. doi:10.1056/NEJMra1806939.
10. What Is a Cardiac CT Calcium Score?. Walter KL. JAMA. 2025;:2835289. doi:10.1001/jama.2025.7567.
11. Effect of Sunscreen Application on Plasma Concentration of Sunscreen Active Ingredients: A Randomized Clinical Trial. Matta MK, Florian J, Zusterzeel R, et al. JAMA. 2020;323(3):256-267. doi:10.1001/jama.2019.20747.