Lawsone – Cosmetic Uses in Natural Hair Colouring and Skin Staining

What Is Lawsone?

Lawsone is the principal colouring molecule found in the leaves of Lawsonia inermis, commonly known as henna. Chemically, it is 2-hydroxy-1,4-naphthoquinone, a naturally occurring naphthoquinone responsible for henna's characteristic orange-red to reddish-brown colour.

Cosmetic Uses of Lawsone

Lawsone is primarily used as a natural colorant and hair-colouring agent. It has a strong affinity for keratin, allowing it to interact with keratin proteins and produce a durable colour on the hair.

Henna preparations can produce warm orange, copper, auburn or reddish-brown shades. The final colour depends on the natural hair colour, concentration and quality of lawsone, application conditions and the presence of other botanical colourants.

Lawsone is also responsible for the traditional use of henna in temporary decorative skin staining. The pigment interacts with keratin in the superficial layers of the skin, producing a stain that gradually fades as the outer skin cells are shed.

Formulation Considerations

Lawsone can be delivered through henna leaf preparations or suitable extracts. The concentration of available pigment, botanical source, harvesting, processing and storage conditions can all influence colouring performance.

pH and application conditions may also affect the release and interaction of lawsone with keratin. Finished products should undergo appropriate stability testing, particularly for changes in colour and colouring performance.

Safety Considerations

Pure, uncontaminated henna has traditionally been used for cosmetic colouring, but allergic contact dermatitis has been reported. Particular care should be taken with products marketed as “black henna,” which may contain para-phenylenediamine (PPD) or other added colourants that are not naturally present in pure henna.

Ingredient Information

INCI: Lawsonia Inermis Leaf Extract
Chemical Name: 2-Hydroxy-1,4-naphthoquinone
CAS: 83-72-7
Chemical Class: Naphthoquinone
Molecular Formula: C₁₀H₆O₃
Molecular Weight: 174.15 g/mol

The exact INCI designation should be confirmed against the raw material specification, particularly when using an isolated lawsone preparation rather than a whole henna leaf extract.

References

Dweck, Anthony. Handbook of Natural Ingredients. Dweck Books.

European Commission. CosIng – Cosmetic Ingredients Database.

National Center for Biotechnology Information. PubChem – Lawsone.

National Center for Biotechnology Information. PubMed – Lawsonia inermis and lawsone.

World Health Organization. WHO Monographs on Selected Medicinal Plants – Lawsonia inermis.

Semwal, R. B., Semwal, D. K., Combrinck, S., and Viljoen, A. M. “Lawsonia inermis L. (henna): Ethnobotanical, phytochemical and pharmacological aspects.” Journal of Ethnopharmacology.

Al-Snafi, A. E. “A review on Lawsonia inermis: A potential medicinal plant.” International Journal of Current Pharmaceutical Research.