Henna is a natural hair dye made from Lawsonia inermis (aka henna plant). When applied to your tresses, henna can make your hair look darker, shinier, and thicker.

When applied to the hair, it forms a coating around the hair shaft and binds to the protein in the hair, creating a semipermanent stain. This can result in a longer-lasting color compared to some chemical hair dyes. Henna can indeed extend the longevity of hair color, as it binds to the hair's keratin and creates a more lasting effect. This depends on the condition of your hair and how often you wash it, but henna usually stays vibrant for around 2 months before gradually fading. However, the effectiveness may vary depending on factors like the initial hair color, henna quality, and how well it's applied. Keep in mind that henna tends to impart a reddish hue, so if you're looking for other colors, results might not be as expected.

Lastly, everyone's hair is unique, so individual results may vary. If you're uncertain about using henna, consider doing a strand test before applying it to your entire head to gauge the color and its longevity on your specific hair type.