PEOPLE are getting less than half the sun protection they expect from sunblock, according to research.

But the problem isn’t the lotion; it’s our slapdash application of it, King’s College London scientists say.

In theory, using sun protection factor (SPF) 15 sunscreen should be enough to stop sun damage.

But in reality, people need SPF 30 or 50 to be safe, say the study authors, who carried out experiments with volunteers in their lab.

Factor 50 lotion applied in the typical way would, at best, provide 40 percent of the expected protection, said Anthony Young, whose team measured how much protection people got from wearing different amounts of sunblock lotions with varying SPF strengths.

Sunscreen needs to be applied thickly enough, which many of us fail to do. SPF ratings are based on the assumption that a 2-milligram blob will cover 1 sq cm of skin.

That means you should apply at least six full teaspoons (36 grams) to cover the body of an average adult.

Areas such as the sides of the neck, temples and ears are commonly missed, so take extra care and apply liberally. It is also easy to forget to reapply sunscreen as often as necessary. People should put it on 15 to 30 minutes before going out in the sun, to allow it to dry. Reapply at least every two hours and immediately after swimming or if it has rubbed off.

Some lotions say they are water resistant, meaning they retain some sun protection properties after immersion. However, up to 85 percent of a product can be removed by towel drying, so you should reapply after swimming, sweating, or any other vigorous or abrasive activity.

And remember: Sunscreens should not be used to stay outside longer or just to avoid more reliable protective measures such as clothing and shade.

(SD-Agencies)

How to apply sunblock

More than half a teaspoon to:

●each arm

●the face, neck and ears

More than one teaspoon to:

●each leg

●chest and abdomen

●back