I was re-reading a book which I bought earlier and found another piece of article which might be of your interest:
“Q: All-in-one shampoo-conditioners are easier to use and more economical, but are they as good?
A: I don’t recommend shampoo-conditioners for the simple reason that they build up quickly and they weigh down the hair. Plus, they should never be used on oily hair. One notable exception is Finesse.
Q: Why shampoo twice?
A: Some experts claim that the first rinse removes dirt, oil, and product buildup and the second adds volume. But it’s really not necessary to lather twice if you do it well.
Q: Are special shampoos for colored, permed, or processed hair really necessary?
A. Yes, they are. Chemically processed hair has special needs. Shampoos for color-treated hair won’t strip the color out the way many other shampoos will, and they contain ingredients that are gentle and moisturizing.
Q: What is clarifying shampoo, and what does it clarify?
A: Clarifying shampoos contain an acidic ingredients, like apple cider vinegar, to cut through built-up residures left by styling products and shampoos. If one is used before you color, perm, or relax your hair, the treatment will absorb better nad go on more evenly. However, they’re too drying to use every day.
Q: What is volumizing or body-building shampoo?
A: These contain proteins that bond to the hair and literally add volume, strand by strand. But if used too often, they can build up a residue that weighs down the hair. If your hair is flat or fine, these work well to create volume, but be sure to alternate them with a regular shampoo.
Q: What does a highlighting or color-enhancing shampoo do?
A: These shampoos are designed to keep your color from fading and add tone to the hair. They can work beautifully to extend the life of your color. They will also add shine to gray hair and help reduce the yellow; and they are good to use after a perm because the peroxide in the neutralizers can lighten the color of your hair.
Q: Do I need sun protection for my hair?
A: Even though studies conducted by Rene Furterer, a French haircare company, show that after three days of unprotected UV exposure, the scales pull away from the hair shaft and make the hair brittle, styling aids and your regular conditioner will coat your hair and give it sufficient protection without additional SPF products. If you spend a lot of time in the sun, do wear a hat to protect your scalp - you should wear one anyway, especially if you color your hair, because the sun will oxidize it and your color will fade.”
(sources: extracted from Beauty The New Basic by Rona Berg.)














