[in-di-GOF-er-a tin-TOR-ee-a]
| Botanical Name | Indigofera tinctoria |
| INCI Name | Indigofera Tinctoria Leaf Powder |
| Common Names | True Indigo, Neeli, Neelini, Black Henna (Misnomer) |
| Part Used | Dried Leaves (Fermented and Oxidized) |
| Key Actives | Indican, Indigotin (Blue Dye), Indirubin |
| Ayurvedic Potency | Bitter (Tikta) | Balances Kapha & Vata |
What is Indigo Powder?
Indigo Powder is a natural, plant-based dye derived from the crushed leaves of the Indigofera tinctoria shrub. Historically referred to as "Blue Gold," this ancient botanical has been used for millennia to dye textiles and hair a rich, deep blue. Unlike synthetic dyes that strip the hair shaft, Indigo Powder functions as a deposit-only colorant. In the context of natural hair care, it is rarely used alone; it is famously paired with Henna to create a spectrum of browns and blacks. While the fresh leaves are green, the powder releases a deep blue pigment upon activation with water and exposure to oxygen.
The Science: How it Works
The coloring power of Indigo lies in its unique chemical transformation. The leaves contain a colorless glycoside precursor called Indican. When the leaves are soaked in water, an enzymatic hydrolysis occurs, releasing Indoxyl. As this paste is applied to the hair and exposed to air, the Indoxyl undergoes oxidation to form Indigotin, the insoluble blue dye molecule.
This molecule binds to the keratin in the hair cuticle through mechanical adsorption. Because Indigotin is a blue-violet molecule, it interacts with the orange-red lawsone molecule (from Henna) to neutralize warmth. The ratio of these two plants determines the final shade: high Henna yields auburns, while high Indigo yields dark browns and jet blacks.
Key Benefits for Hair
- Safe, Permanent Coloring: Unlike synthetic dyes containing PPD or Ammonia which penetrate and damage the cortex, Indigo coats the hair shaft, providing permanent color without compromising structural integrity.
- High-Gloss Shine: The coating action of the Indigotin molecule smooths the hair cuticle, reflecting light and creating a "mirror-like" shine often missing from chemically treated hair.
- Scalp Health & Dandruff Control: In Ayurveda, the plant is known as Neelini and is valued for its antibacterial and antifungal properties, making it effective for soothing scalp irritation and reducing dandruff.
- Hair Texture & Volume: Regular use of Indigo Leaf Powder can make fine hair feel thicker and more voluminous, as the dye particles build a protective layer around each strand.
Natural Indigo vs Synthetic
It is crucial to distinguish between Natural Indigo (plant-derived) and "Black Henna" or synthetic indigo dyes. Synthetic variants are often coal-tar derivatives or contain Para-phenylenediamine (PPD) to accelerate the dyeing process. These synthetics can cause severe allergic reactions and chemical burns. Spierb’s Indigo is 100% pure Indigofera tinctoria leaf powder, ensuring the dye released is the natural Indigotin molecule, free from metallic salts and adulterants.
Safety & Contraindications
Indigo Powder is generally considered safe for external use on hair and scalp. However, it is a fine dust that can irritate the respiratory tract; always wear a mask when mixing the dry powder. While rare, sensitization can occur. A patch test is mandatory 24 hours before full application.
Note: Indigo should strictly be used on hair. It is not recommended for body art (tattoos) unless specifically formulated, as pure Indigo paste has a "sandy" texture compared to Henna. Avoid using on hair that has been recently chemically bleached without a strand test, as the interaction may result in unwanted green hues.
