Which sunscreen, if any, should I use?

Improved knowledge related to the sun and technology advances have made sunscreen issues more complex. Which sunscreen would be best for you, depends on many factors such as how sensitive your skin is to burning and to cosmetics, how dry or oily your skin is, previous sun and skin cancer history and your medical history

Sunlight generates warmth (infra-red) that we can feel, visible light (that our eyes can see in daylight) and ultraviolet light (UVL) which we cannot see or feel but which can penetrate our skin. The UVL that reaches the earth is grouped into shorter UVB and longer UVA wavelengths. Our skin makes Vitamin D from small amounts of UVB but larger amounts may cause burning and contribute to skin cancers. UVA penetrates deeper. Large or prolonged exposure may also cause burning, premature skin ageing and skin cancers. Both UVA and UVB suppress skin immune function. Heat and wind can exaggerate the damaging effects of ultraviolet light. New Zealand’s UVL is stronger from September to April so the daylight saving months are a good guide to when sunscreens may be needed regularly.

SPF stands for sun protection factor. This tells us how much longer we could expect to be exposed to UVB before burning compared to no sunscreen. The higher the number, the better is the expected protection. It is still being resolved internationally how to best rate UVA protection. Meanwhile choose a sunscreen that offers broad spectrum cover. In the future sunscreens may also include immune protection factors.

Sensitive skin

If you have fair skin that burns easily you should choose a broad spectrum sunscreen with a high SPF e.g. 30+ If you have skin that tans readily you could choose a broad spectrum sunscreen with intermediate SPF e.g. 8-15+ If you have darkly pigmented skin and do not suffer from a sun / photosensitivity problem, you do not need sunscreen.

If you have sensitive skin that has trouble tolerating sunscreens or cosmetics, look for hypoallergenic / low irritant sunscreens. You may like to try a variety of sunscreen samples before deciding what you will use regularly. If you are still having rashes you might need to undergo allergy patch testing to identify a particular ingredient in sunscreens that is causing the problem. Talk with your dermatologist about this if necessary.

Dry / Oily skin

If your skin is dry you would benefit from a sunscreen with a moisturising base e.g. sunscreen creams or ointments. If you have oily skin or readily develop acne, choose a sunscreen in a lighter base, e.g. lotion or gel. Lighter sunscreens are also better in hairy skin areas.

Activity

If you plan to be active outdoors and may get wet or sweaty, choose a sunscreen that is water resistant and likely to be longer lasting or rub resistant.

What about Vitamin D?

If you have fair skin you may need only 5 minutes of midday summer sun activity in shorts and t-shirt without sunscreen to make enough. You will need longer or greater skin exposure if your skin is darker. Being physically active outdoors helps you make more Vitamin D than resting in the sun. If you are over 50 years old (ageing skin is not as good at making Vitamin D), immunosuppressed or have had previous skin cancers, you are better to apply sunscreen and talk to your doctor about Vitamin D supplements.