How to Choose a Sunscreen in Your 40s and Beyond

If there is one skin care product that dermatologists agree on, it is sunscreen. UV light is the main cause of the wrinkles, spots and texture changes we associate with aging, as well as skin cancer. Mayo Clinic names sun exposure as a leading cause of wrinkles, and MedlinePlus describes how sun damage builds up over the years.

The good news: it is never too late to start. Protecting your skin now helps prevent further damage and lets other treatments, like retinoids, work better. This guide explains what to look for and how to use sunscreen properly.

The three things to look for

The American Academy of Dermatology (AAD) recommends a sunscreen that offers:

1. Broad-spectrum protection. This means it protects against both UVA rays, which contribute to aging and skin cancer, and UVB rays, which cause sunburn and skin cancer.
2. SPF 30 or higher. SPF 30 blocks about 97% of UVB rays. Higher SPFs block slightly more, but no sunscreen blocks 100%.
3. Water resistance. Water-resistant sunscreens stay effective for 40 or 80 minutes while swimming or sweating, as stated on the label.

Mineral or chemical?

Sunscreens use two main types of active ingredients.

The AAD notes that people with sensitive skin may do better with mineral sunscreens containing zinc oxide or titanium dioxide, which are less likely to irritate. Both types protect your skin when used correctly.

Picking a formula for mature skin

Midlife skin is often drier and more sensitive, so texture matters:

• Dry skin: cream or lotion formulas, often combined with moisturizing ingredients like ceramides or hyaluronic acid.
• Oily or acne-prone skin: lightweight gels or fluids labeled "non-comedogenic."
• Sensitive skin or rosacea: fragrance-free mineral formulas.
• Uneven tone or melasma: tinted mineral sunscreens containing iron oxides can help protect against visible light, which can worsen dark patches.
• Wearing makeup: a moisturizer or primer with SPF 30 works, as long as you apply enough. Powder or spray sunscreens can be handy for reapplying over makeup, but they are hard to apply in sufficient amounts on their own.

How much to use

Most people apply far less sunscreen than the amount used in testing, which means they get less protection than the SPF number suggests. The AAD says most adults need about one ounce, enough to fill a shot glass, to cover the exposed areas of the body.

For the face and neck, a common guide is about a nickel-sized amount for the face alone, or two finger-lengths of lotion for face and neck. Do not forget:

• Ears
• The back of the neck
• The tops of the feet
• The backs of the hands
• The scalp along your part (or wear a hat)
• Your lips, using a lip balm with SPF 30

When to apply and reapply

• Apply 15 minutes before going outside, so it has time to settle on the skin.
• Reapply about every two hours when outdoors, and right after swimming or sweating heavily, according to the AAD.
• Wear it daily, even on cloudy days. Up to 80% of UV rays can pass through clouds, and UVA rays pass through car and home windows.

Beyond sunscreen

Sunscreen is one part of sun protection. The AAD also recommends:

• Seeking shade, especially between 10 a.m. and 2 p.m., when UV rays are strongest.
• Wearing protective clothing, such as a wide-brimmed hat, UV-blocking sunglasses and long sleeves. Clothing labeled with an ultraviolet protection factor (UPF) offers reliable protection.
• Avoiding tanning beds, which increase skin cancer risk.
• Taking extra care near water, snow and sand, which reflect UV rays.

Sunscreen and vitamin D

A common worry is that sunscreen will cause vitamin D deficiency. In everyday life, most people do not apply sunscreen thickly or often enough to block all vitamin D production, and vitamin D is available from food and supplements. The NIH Office of Dietary Supplements notes that experts recommend protecting the skin from the sun to reduce skin cancer risk, and that people can get vitamin D from food and supplements. If you are concerned, ask your clinician about testing. Our guide to calcium and vitamin D after 40 covers the details.

Common sunscreen myths

• "My makeup has SPF, so I'm covered." Only if you apply a lot of it, which most people do not. Use a dedicated sunscreen underneath.
• "Darker skin doesn't need sunscreen." Everyone can get sun damage and skin cancer, and sunscreen helps prevent dark spots and melasma.
• "I'm indoors all day." UVA passes through windows. If you sit near a window or drive a lot, daily sunscreen still helps.
• "Higher SPF means I can stay out longer." No sunscreen gives all-day protection. Reapply and seek shade.

The bottom line

Choose a broad-spectrum, water-resistant sunscreen with SPF 30 or higher in a texture you enjoy. Apply enough, about a shot glass for the body and a generous amount for the face, reapply every two hours outdoors and wear it every day. Pair it with shade, hats and sunglasses. It is the single most effective step you can take to protect your skin in your 40s and beyond.

Frequently asked questions

Is SPF 50 much better than SPF 30?

SPF 30 blocks about 97% of UVB rays and SPF 50 blocks about 98%. The bigger difference usually comes from applying enough and reapplying.

Should I use mineral sunscreen if I have sensitive skin?

Many people with sensitive skin or rosacea find mineral sunscreens with zinc oxide or titanium dioxide less irritating, as the AAD notes. Fragrance-free formulas are also helpful.

Do I need sunscreen if I work indoors?

UVA rays can pass through windows, so if you sit near windows or drive often, daily sunscreen is still a good idea.

How long does sunscreen last in the bottle?

Sunscreens are required to remain at their original strength for at least three years. Check the expiration date and throw it out if it has changed in color or consistency.