I am quite confused when it comes to choosing a suitable shampoo/conditioner. Is there a guide to picking the right ones?

You have raised a question of extreme practical importance.

First, a bit about shampoos. Shampoos are specialised cleansers designed to beautify hair and in some cases treat or prevent certain scalp diseases.

They are intended to remove sebum, sweat components, dead skin cells, styling products and environmental dirt from hair. Shampoos are a complex formulation containing detergents, foaming agents, conditioners, thickeners, opacifiers, keratolytic agents, softeners, fragrances, preservatives and many other additives.

Detergents are the primary sebum and dirt removal components but their excess can leave the hair dull, susceptible to ‘static electricity’ making it difficult to comb. Shampoos claiming high cleansing, antibacterial or antifungal properties have increased detergent concentration.

Then there’s the issue related to the pH value of the shampoo. Anionic detergents make high pH-value shampoos and claim deeper cleansing, but usually leave the hair harsh and dry. Cationic chemical characteristics make shampoos with lower pH values. These shampoos have relatively poor detergent effect and do not lather well. Cationic detergent shampoos are excellent at imparting softness and manageability of hair. The third group of shampoos is formulated with nonionic detergents are considered to be mildest and are most popular. Most people believe that shampoos generating maximum foam are better cleansers than poorly foaming shampoos; this is not true.

Use of conditioners is also a popular consumer choice. They impart manageability, gloss and anti-static properties to hair. Many of the 2-in-1 shampoos for dry, damaged or treated hair already contain these conditioners. Therefore there isn’t any need to use a separate conditioner. Conditioners made with hydrolysed animal protein are probably the best for extremely dry hair and for those complaining of split ends.

The effect and feel of a shampoo and conditioner are influenced by a few factors including type of water. Using extremely hard water, may leave a residual film of detergents which may contribute to an itchy scalp. Some marketed shampoos are alkaline with high pH value. This can swell the hair shaft making it more susceptible to get easily damaged. A few manufacturers use extra additive ingredients to alter the pH value so that they can be marketed as ‘pH-balanced shampoos’.

Incidentally, chemically there are no differences between shampoos and conditioners for men and women.