Sun lotion vs sunscreen: what's the difference?

Compare the protection, not the name

Sunscreen describes a product's protective function; lotion describes one of its forms. Compare the SPF and broad spectrum label rather than the product name, which is doing considerably less work.34

What should the label say?

Choose broad spectrum protection, SPF 30 or higher, and water resistance. Broad spectrum covers UVA and UVB, the harmful ultraviolet rays from the sun. SPF mainly describes protection against UVB, which causes sunburn; the SPF number alone does not tell you the UVA protection. A higher SPF is not permission to stay outside longer without reapplying.245

For swimming or sweating, check the water resistance duration. US labels specify 40 or 80 minutes. No sunscreen is waterproof, and water resistance does not remove the need to reapply.4

Which should you choose?

Choose a lotion if that is the format you prefer to use regularly; sunscreen has several formats, not a dress code. Creams suit dry skin and facial application, while gels suit oily complexions and hairy areas. Sticks are useful around the eyes. A sunscreen lotion does not need replacing simply because another bottle says sunscreen more prominently.25

For sensitive skin, mineral sunscreens containing zinc oxide or titanium dioxide are an option. Some products combine mineral and chemical filters. Try a small amount on your arm and check for a reaction for up to 48 hours. Fragrances and preservatives can also cause reactions, so changing filter types alone does not address every sensitivity.126

How to apply either one

1. 1Read the label, then apply generously and evenly to dry skin 15 minutes before going outdoors.
2. 2Cover all exposed skin. Most adults need about one ounce for exposed body skin; body size and coverage affect how much you need.
3. 3Include your ears, neck, hands, tops of feet, hairline and exposed scalp. Protect lips with an SPF 30 lip balm.
4. 4Reapply at least every two hours outdoors, and after swimming, sweating or towelling off. Follow the bottle's water resistance directions.

Use sunscreen on uncovered skin when going outside, including cloudy days. Pair it with shade, protective clothing, a hat and sunglasses: sunscreen alone cannot fully protect you. Ask a doctor before applying sunscreen to a baby younger than six months; shade and protective clothing are the first choice.245

Does last summer's bottle still count?

Discard sunscreen past its expiry date. For a bottle without an expiry date, discard it three years after purchase, or if you do not know its age. Keep the container out of direct sun and excessive heat. Storage matters whether the front says sun lotion or sunscreen.4