Lather, Rinse and Repeat
Most of us just follow directions without giving it much thought – Lather, Rinse and Repeat. We wet our hair, apply enough shampoo to produce a lather, rinse, and then lather again. Although that’s what we’ve always done, all hair isn’t the same and the same procedure will not produce the best results on different types of hair.
Fragile, dry hair, that was just shampooed the day before, is still relatively clean and should be treated differently than resistant, oily hair that hasn’t been shampooed in a few days or longer. The shampoo procedure should vary depending on the type and condition of the hair and how often it’s shampooed.
A good shampoo usually starts by wetting the hair with water and even plain water damages your hair. Water breaks hydrogen bonds and swells the hair about 18%. Hot water swells the hair more than warm water. So always use warm or cool water, rather than hot. Although there is no reason to be uncomfortable, if you are willing to try a final rinse with cold water, your hair will tangle less and have more shine.
The surfactants in shampoo clean our hair in exactly the same way they clean our dishes and our clothing. Surfactants surround and enclose a drop of oil or speck of dirt to form a sphere called a micelle. The micelles attach to the water to form an emulsion and the emulsified oil and dirt is carried away with the final rinse.
Lather forms when surfactants form micelles around air instead of oil or dirt. It’s important to note that lather will not form until all the dirt or oil has been emulsified. At that point, any excess surfactant will produce lather. So, once you’ve applied enough shampoo to produce lather, you know that all of the oil and dirt is emulsified and your hair is ready to rinse.
Although everyone loves a rich, thick, creamy lather, it isn’t really necessary. A modest, uniform later indicates your hair is ready to rinse. Once you have obtained lather, there is no point in adding more shampoo. A thick, robust lather means you used more shampoo than needed and caused unnecessary damage to your hair. Excess surfactant may strip and damage hair. If you have fragile, dry hair and shampoo daily, a single lather may be enough. A second lather does nothing more than insure your hair is clean.
Oily hair should be treated differently. Oils, such as sebum, are insoluble in water. Sebum combines with dead skin cells and other dirt to form an oily coating on the hair and scalp that is difficult to remove. Wetting oily hair with water first, will make the oil more difficult to remove. Oily hair should not be wet with water before shampooing. Apply shampoo directly on the oily areas while the hair is still dry. Then add just enough warm water to massage the shampoo into the hair. Rinse thoroughly and apply enough shampoo to get a second lather. You’ll use less shampoo and get better results.
The same is true for removing peanut butter or any other oily substance from the hair. Always apply shampoo directly to the oily area on dry hair. Then add water and shampoo.
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