Derived from a biotechnological or synthetic process, the dihydroxyacetone (DHA) is a colouring agent found in certain hair care and self-tanning products. Let's focus on the use of this compound on hair.
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Dihydroxyacetone, an effective ingredient for hair?
Summary
- Dihydroxyacetone in a nutshell
- Dihydroxyacetone for hair: the active ingredient in natural dyes
- The precautions for using DHA-based tanning products
- Source
Published February 22, 2022,
updated on June 20, 2024,
by
Maylis, Chemical Engineer
—
4 min read
Dihydroxyacetone in a nutshell.
The dihydroxyacetone is a triose molecule, meaning it is a sugar composed of three carbon atoms. It is naturally found in plants such as chestnut bark. However, it can also be obtained through a biotechnological process. This involves a stage of microbial fermentation from glycerine extracted from certain plants like sugarcane, beetroot, corn, rapeseed, among others. The DHA thus obtained appears as a white crystalline powder soluble in water and ethanol but insoluble in oil.
DHA acts as a colouring agent ; it is primarily used as an active ingredient in self-tanning products and natural hair dyes. Upon contact with the amine functions carried by the amino acids present in the dead skin cells and/or hair fibres, DHA reacts according to the Maillard reaction to form heterogeneous polymers called melanoidins which are responsible for the brown colour.
Dihydroxyacetone for hair: the active ingredient in natural dyes.
Dihydroxyacetone (DHA) is a colouring agent that is typically used in the composition of natural dyes, also referred to as non-oxidising dyes. Among other things, it helps to conceal grey hair that may appear over time.
As a reminder, traditional hair dyes, known as oxidative, colour the hair by replacing its natural pigmentation. This type of dye acts on the hair's structure, as it penetrates the cuticles. This allows the hair's melanin to be replaced by the chosen colour. However, it should be noted that this type of dye can be harsh, hence the importance of using suitable care (moisturising and repairing) following its application.
Unlike traditional dyes, natural non-oxidising dyes rich in DHA colour hair without altering their structure. They act solely on the surface, in contact with the keratins present on the hair fibres. The use of this type of treatment allows the hair's shine to be preserved as the keratin remains intact. Let's remember that keratin is a natural protein that acts as a protective barrier for hair fibres by forming the hydrolipidic film.
It should be noted that, as they act on a superficial level, DHA-based colourings are, however, temporary. To maintain the colour, it is therefore necessary to space out shampoos and reapply the colour a few weeks later. Moreover, prior preparation can help prolong the colour. A scalp exfoliation is particularly necessary to remove dead cells and revitalise the hair. You can therefore use our scalp exfoliator PHA 5% + jojoba beads in advance. This pre-shampoo exfoliating gel gently removes dead cells for a healthy and balanced scalp.
The precautions for using DHA-based tanning products.
The use of DHA in hair dyes has recently been regulated. The maximum concentration of DHA allowed in hair care products is therefore 6.25%. Regardless, this active ingredient is not subject to any contraindications. It can be used without fear, knowing that it does not cause any adverse effects. However, as hair dyes can contain other ingredients, a patch test on the inside of the elbow with the product in question is still recommended to avoid allergic reactions. In case of redness or itching, the use of the product should be discontinued.
Source:
CIRIMINNA R. & al. Dihydroxyacetone: An updated insight into a significant bioproduct. ChemistryOpen (2018).
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