system
Given the following post, respond as if you're commenting on Reddit:
human
Are different brands and types of shampoo and conditioner really chemically calibrated to do what they promise?

I've always been curious whether there are really chemical compounds that "promote bounciness" or "reduce frizz." Or is it basically the same soap dressed up in different packaging?
gpt
The active ingredient in all shampoos is some type of detergent, usually sodium lauryl sulfate (SLS), which uses its amphipathic properties to dissolve both polar and non-polar residues in your hair. Conditioners basically contain the same thing, but contain much less SLS and much more additional oils and proteins that help your hair retain moisture and body after shampooing. The main difference between shampoos is the concentration of SLS in the product. SLS's main function is to remove the naturally excreted oils (sebum) your hair produces, and since this varies greatly from person to person, some people respond better to products with different concentrations of SLS. For example, if you use a shampoo that's for "oily hair" it probably contains a higher concentration of SLS to help dissolve the oils. If you were to use this product on your "dry and frizzy hair," it would exacerbate the problem. Basically, this is the BASIC idea behind using different formulations of shampoo, but other compounds can be added to the product to "promote bounciness." One is the protein albumin (the egg white protein), which denatures in the product and acts like a sticky glue that firms up your hair. Additionally, products can also control for hair pH, smell nice, and moisturize your scalp to reduce oil secretion or flakes. 

All in all, it's a balance between cleaning the hair and over-cleaning the hair, which dries it out and leads to "frizziness." The shampooing and conditioning cycle is summarized as: remove all natural oils without overdrying (shampoo), readd those oils in the right amount to reestablish the moisture and pH (conditioning).