We're faced with an ever more dazzling array of sunscreens these days. So, on the off chance that the weather is sunny this weekend, here's how to choose the best sun protection for you, plus a few common sense precautions. Why bother?Your skin typeWhat's the difference between UVA, UVB and UVC?Choose the right SPF What's the difference between sunscreen and sunblock?Common sense precautions

Why bother?
It's a good question. Although sunscreens can be expensive, over-fragranced and greasy, and some people may think they're an unnecessary luxury, the case for sun protection is this simple:

• sun exposure causes skin cancer
• skin cancer is the commonest form of cancer in the United Kingdom. Recent estimates suggest that there are now around 4,000 new cases of malignant melanoma, the most dangerous form, each year.

Apart from perhaps staying indoors all day, nothing will completely protect you from skin cancer. However, using a sunscreen along with adopting a sensible attitude towards sunshine will help you to protect yourself against its harmful effects: sunburn, sunstroke and premature ageing, as well as skin cancer.

Your skin type
For all skin colours/types, the minimum SPF you should choose is 15. There are also special hypoallergenic types of sunscreen available for very sensitive skins.Fair, light and freckly skinned people who rarely tan and always burn should always use a high SPF of 20 to 30. Brown or olive skinned people are at a lower risk of sunburn over any given time period than light skinned people, but still need to take care especially under a midday or tropical sun.

Black skinned people who rarely burn still need to use some sunscreen, although the risk of both burning and getting skin cancer is low.

If you have a family history of skin cancer, you may be more at risk of skin cancer yourself. To minimise the risk of skin cancer, it would be best to avoid exposure to the sun at all times; however, most of us enjoy being in the sunshine, so the next best thing is to make sure you choose a high SPF and follow the common sense precautions. It would also be advisable to wear an SPF 15 all year round - men and women. It's also worth remembering that most sun damage occurs before the age of 15, so it's very important to protect children's skin from the earliest possible age. We recommend NeoStrata product line which combines moisturizing properties with High SPF protection. Some examples: Oil free lotion SPF 15 PHA 4 (8318), Daytime Protection Cream SPF15 PHA 10 (8414), Ultra Smoothing Cream SPF 15 AHA 10 (8006)

What's the difference between UVA, UVB and UVC?
UVA, UVB and UVC are all types of radiation that are given off by the sun. UVC is absorbed by the atmosphere and never reaches the earth's surface. UVB is partially absorbed by the earth's ozone layer and in the atmosphere, with the remainder reaching the earth's surface. Most UVA reaches the earth's surface.

UVB is commonly associated with sunburn, and together, UVB and sunburn are considered to be the main cause of basal and squamous cell carcinoma, as well as a significant cause of malignant melanoma. UVA, which penetrates deeply into the skin, is also thought to be a factor in premature ageing and skin cancers.

Unlike the SPF rating, there is no universal standard for rating the level of UV protection in a sunscreen. However, most sunscreens do now carry a star rating, choose one with more stars rather than less.

Choose the right SPF
SPF (Sun Protection Factor) is a common indicator of UVB absorption provided by manufacturers which you will find on the labels of these products. This rating goes from as low as 2, up to 30 and above. The minimum SPF you should choose, no matter what your skin colour/type, and no matter the time of year, is SPF15. Bear in mind that parts of the body that are especially sensitive eg lips or rarely exposed to sunlight eg backs may need a higher factor or a sunblock.

A higher SPF does not give you higher protection, it gives you longer protection from the effects of the sun. So, if your skin would redden after 30 minutes if you didn't use any sunscreen, an SPF 2 would allow you to stay in the sun for 60 minutes before you redden.

This is only true in theory however, as a sunscreen's effectiveness depends:

• on how thickly and frequently you apply it
• what activities you do. If you swim or sweat a lot, the sunscreen won't last as long.

Remember, your skin can still redden up to 24 hours after exposure to the sun, so burning may not be immediately obvious.

Skin type Reaction to sun

• Very fair /sensitive Always burns, rarely tans Fair/sensitive Burns easily, but will tan
• Fair Tans gradually, likely to burn first
• Medium Tans well, unlikely to burn first
• Dark Tans easily, rarely or never burns

Please note that the SPF given is just a guide. Always follow the manufacturer's instructions for each sunscreen and always practise safe sun!

What's the difference between sunscreen and sunblock?
Sunscreens absorb UV rays, while sunblocks deflect them. A sunblock, properly applied, prevents all UV from reaching the skin. Sunblocks used to be easily recognisable as the bright white stripes that skiers and lifeguards once wore; they are now much more cosmetically acceptable.Common sense precautions Dr Patel recommends the following:

• choose a sunscreen with a minimum of SPF15, higher if you're very fair skinned or have sensitive skin, have freckles or moles, or a history of skin cancer, or for use on children. Try a sunblock stick for lips cheeks and nose

• put your sunscreen on at least 20 minutes before you go out. Don't skimp on quantity and make sure you cover all exposed areas especially the back of your neck, and areas which don't see much daylight, such as your stomach and back

• re-apply the sunscreen frequently, especially after swimming or playing sport. A waterproof version may be best for you

• stay in the shade between 11am and 3pm, because the sun is at its strongest during this time

• don't be fooled by clouds, fabric umbrella shades or even clothes. You can burn through all these things. Many clothes do not block out UV rays, so even making your children wear T-shirts may not be enough. Watch out for special clothes that do provide UV protection

• take extra care in, on and around water, as water reflects the sun's rays, and will make you burn more easily

• wear a hat that covers your face and the back of your neck

• drink lots of water to help prevent dehydration

• if you do burn slightly, calamine lotion or yoghurt can help cool your skin, or take a cool bath or shower. If you have a more serious burn you should see your GP