Mayonnaise is good for the overall condition of hair. Mayonnaise is made with oil, which makes hair soft and shiny, and serves as a conditioning treatment prior to shampooing.
To condition your hair before shampooing, apply mayonnaise to dry hair and cover with a warm towel for 20 minutes. Massage shampoo liberally through hair before showering to break down excess oil.
The smell and texture of mayonnaise can be off-putting. Mixing in a teaspoon of vanilla extract helps cut the mayonnaise scent. Hot oil treatments, sold by most hair care companies, are a convenient alternative. The oils in these treatments provide hair with the same benefits as mayonnaise.