How does natural hair dyes work?

Permanent hair dyes or synthetic dyes, contain chemicals such as ammonia or its substitutes that enables the diffusion of the tint into the cortex of the hair fibre to break up the melanin (the natural dye molecule of the hair) and replaces it with a new colour. Bleaching and hair lightening works similarly to enable the diffusion of the melanin in the cortex.

Natural Ingredients, such as henna are tannins similar to black tea and are acidic in nature and stain naturally. Some tannin such as Henna seems to work better at retaining a colour on hair compared to other tannins such as tea. Henna contains a dye molecule called Lawsone which is orange/red in colour. When henna is coated on the hair, lawsone is absorbed into the outer layers of the hair (keratin) and creates a colour shade that is a mixture of the natural colour of the hair (melanin) and orange/red (from lawsone). Grey hair for example, has no melanin and will result in orange/red hair if dyed using henna.

The lawsone molecule with henna is more effectively extracted by soaking henna in a slightly acidic medium such as lemon juice/black tea over 4 - 6 hours, which helps to break down the chlorophyll in henna leaves. The orange/red colour of lawsone can be moderated/enhanced using apple cider, cinnamon, rosemary or amla powder although its final effect will depend on the natural colour of the hair.

Natural Indigo is different from henna in that it should not be kept on hair for more than 1.5 hours as it will tend to oxidise in air. The colour will darken in time as the indigo oxidises on exposure to air. It will result in blue/purple or green colour on grey hair if applied by itself. Colouring hair with a mixture of henna and indigo powders will tend to result in dark brown colour on grey hair. To get jet black hair, the best result is obtained if indigo is applied after hair is dyed using henna or by using a mixture of henna and indigo powder.

Hair can be shampooed or conditioned after an application of henna/indigo. There is no easy or natural way to remove the effect of lawsone or indigo once the colours have set. The colour will fade in around 4 - 6 weeks. Although the application of these ingredients does take time, the most important aspect in considering the use of these ingredients is that it will not damage hair.

What is Brown, Blonde, and all of those other colors of Henna?

Some Blonde, Brown, Auburn, Mahogany, and other “shades” of henna are mixes of amla, indigo, walnut, rhubarb, and henna. Many variations of Henna have synthetic dyes or metallic salts added. Many of these products have no henna whatsoever and are chemical dyes. Our recommendation is that users of henna, satisfy themselves by checking the ingredient list. Lawsonia inermis - is the only plant that is actually “real henna” and it is light to medium/dark green in colour. Certified organic ingredients cannot contain synthetic ingredients, hence certfied organic coloured henna should be reviewed with caution.

Is there a good site for information on Henna?

Please click on the following link: Henna for Hair