When skin is exposed to the harsh sun or a source of heat, it can cause burns, result in darkening and ageing. There is added risk of getting skin cancer. The UV or ultra-violet rays of the sun affect the skin. There are two categories of UV rays — UVA rays are more harmful as they cause long term damaging effects on the skin and UVB rays which are less harmful as they cause sun burns and photo ageing. Sun Protection Factor ( SPF ) is the criterion of the rating of sun protection offered by a product. These products are of two kinds — sunscreens which allow a little filtering of UVB rays in the skin,and sunblocks ( which contain zinc oxide ) that deflect UV rays from the skin altogether. SPF is calculated by the amount of time needed to cause a sunburn on protected skin to the amount of the needed to cause a sunburn on unprotected skin. Sun protection production have an SPF ranging from 2 to 90. Physical sunscreen have an SPF of 20 and very less chemicals. Sunscreen with chemical’s have SPF exceeding 20, and as the amount of chemical increases, the SPF increases. In indoor conditions, say in a kitchen, one can use a product with SPF exceeding 20, and as the amount of chemical increases, the SPF increases. In indoor conditions, say in a kitchen, one can use a product with SPF 15. As water washes away the product, one can used waterproof sunscreens while swimming. As chlorine in water makes the skin dry, one become susceptible to tanning. One has to use sunscreens with SPF more than 30 because lesser than 30 offer only partial protection. These preparations offer protection for 3-4 hours against UVB rays but not much against UVA rays. Therefore, one has to use these products every 2-3 hours, especially when outdoors. These products can be mixed with moisturizers. To avoid stickiness, calamine lotion can also be mixed.

Sunscreens do not affect the absorption of vitamin D from sunlight. Oily skin can cause and worsen existing acne. Oily sunscreens therefore are avoided. One should use gel or lotion-based sunscreen. Also sunscreen with matte effect should be used.