Now the question arises how often you must shampoo. Women are advised to shampoo once every 8 to 10 days for normal hair, once every fortnight for dry hair and once every 5 to 8 days for oily hair. I would like to mention that too frequent washing of hair, however good the quality of the shampoo used, can in the long run cause damage to the hair. There is at present available, a wide range of products for washing hair (from ordinary soaps to medicated shampoos!) Buy these products preferably from a chemist shop or a reputed general store.
There is a large variety of liquid shampoos presently available in the market. These synthetic detergents were developed during 1939–40. These soapless shampoos, whether used in hard water or soft water, leave no white deposit on the hair when dry. They also clean the hair more thoroughly due to their greater lathering and emulsifying power. Do not use ordinary household detergents to wash the hair. These are crude, very alkaline and can act as an irritant. Manufactures usually add to the refined detergents– soapless shampoo, perfume and other products such as lanolin and lecithin to render the hair supple and glossy after washing.
These shampoos are used to correct any disorder of secretion in the scalp. If you have dry hair, choose a shampoo based on cod oil, tar or lecithin. If you have oily hair, a shampoo containing sulfur or essence of cedar is best. There are dry and coloring shampoos which come in an extremely fine powder which is sprinkled over the hair and then removed by very thorough brushing. Their main advantage is that no wetting of the hair is required. They consist of a mixture of synthetic detergent in powder form and mineral salts. Mostly sodium salts are used which absorb fatty matter. Thus the hair can be cleaned without too frequent washing, and because of this they are particularly recommended for oily hair.
Coloring shampoos have become very popular in recent years for brightening the color of the hair. They are in fact good shampoos with a detergent base to which has been added either a bleach or a dye which is much less harmful than the real dyes because it does not penetrate the hair but only covers it with a thin coloring film. Coloring shampoos are generally harmless, but they can affect those who are susceptible to allergies, by causing an eczema on these severe allergies, do not use coloring shampoos during periods, pregnancy, menopause, ovarian upsets, and skin troubles.
To carry out a shampoo properly, begin by soaking your hair in hot (not too hot) water. Too hot water is not good for the hair or the scalp. Pour on to the hair a small quantity of shampoo and rub the scalp with the tips of your fingers vigorously. If your hair is long or very thick, slip your fingers right through the hair to the scalp itself, and rub it vigorously but not roughly. Next rinse completely with hot water, and again apply a lot of shampoo. Rub in, but this time more with the hands flat. Do not penetrate through to the scalp, but gently rub the hair. The shampoo should foam cleanly. If not, apply more shampoo for the third time. The rinsing which follows must be very thorough. Rinsing should not stop until the water from this fast rinse is completely clear. At the slightest trace of soap or foam, at the slightest tingling from the scalp, do not hesitate to carry out an extra rinse. Next you should wring the hair, but never twist it, in a thick towel. Wrap the dry towel like a turban around your hair. A hair dryer can also be used for this purpose, but avoid too hot air.