There are two basic bases for homemade shampoos: baking soda and Castile soap mixed with coconut milk. Baking soda tends to work better for normal to oily hair while Castile soap works well with dry hair.
Baking soda is an excellent ingredient for homemade cosmetics. It is a key part of many dry and liquid shampoo recipes. For a dry shampoo, mix one part baking soda with one part cornstarch. This absorbs oil, dirt and smells. To make liquid shampoo, mix one part baking soda with one part water in a squeeze bottle.
Although baking soda is a much gentler alternative to most commercial shampoos, it can be hard on dry or fine hair. It may also irritate sensitive skin. Castile soap makes a great alternative. Liquid or melted Castile soap mixed with an equal part coconut milk makes a fantastic homemade shampoo base for dry or fine hair.
Essential oils can give homemade shampoos a boost. First, they smell wonderful and provide an element of luxury to homemade cosmetics. Second, they can improve the effects of the shampoo. Tea tree oil helps reduce oil and kills germs and fungus. This helps fix dandruff and similar hair problems. Lavender and rose oils help nourish the scalp and hair without causing additional oil buildup. Mint essential oil has a refreshing property and can sooth an irritated scalp.
Vitamin E oil, almond oil and olive oil can help nourish dry, brittle hair. However, they are not appropriate for oily hair. In addition, olive oil and almond oil may weigh down fine hair types.