Hydrolyzed Keratin and Macadamia Oil: Molecular Complementarity on the Hair Fiber

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Keratin and macadamia oil are two of the most thoroughly researched and valued ingredients in professional hair cosmetics. Understanding their chemistry, mechanisms of action and practical applications is fundamental for any hair professional. Hairswiss analyses both in depth.

What Is Keratin and How Is It Structured

Keratin is a fibrous structural protein that makes up approximately 85–95% of the hair’s composition. It belongs to the family of α-helix proteins: its polypeptide chains coil around each other to form an extremely resilient triple helix, rich in cystine — an amino acid that forms disulphide bridges (S–S bonds) giving hair its mechanical strength and elasticity.

In cosmetic products, two main forms are used:

  • Hydrolysed keratin: low molecular weight peptide fragments (<1,000 Da) capable of penetrating the hair cortex.
  • Native keratin: higher molecular weight, acts mainly on the surface forming a protective film over the cuticle.

How Keratin Acts on the Hair

Damaged hair progressively loses its protein content. Hydrolysed keratin intervenes by: reconstructing the protein matrix through bonding to damaged zones; reducing porosity by sealing micro-cracks in the cuticle; and reducing frizz thanks to its antistatic action.

Keratin Safety: The Formaldehyde Question

First-generation keratin smoothing treatments used formaldehyde as a fixing agent. Formaldehyde is classified by the IARC in Group 1 — definite human carcinogen, with real risks through inhalation during high-temperature application. Modern professional formulations have progressively eliminated formaldehyde in favour of alternative systems (glycolic acid, cysteine, glyoxylate, nanoplasty technologies). Professionals must always check the product data sheet and work in adequately ventilated environments.

What Is Macadamia Oil and Why Is It Exceptional

Macadamia oil is extracted by cold pressing from the seeds of Macadamia integrifolia. It is one of the plant oils whose lipid composition most closely resembles human sebum. Its chemical composition is dominated by:

  • Palmitoleic acid (C16:1): 17–22%, a unique value in the plant world. It is the same fatty acid produced by human sebum, which decreases naturally with age.
  • Oleic acid (C18:1): approximately 55–65%, responsible for moisturising properties and the ability to penetrate the hair fibre.
  • Vitamin E (tocopherols): natural antioxidant action protecting the oil from rancidity and the hair from free radicals.

Synergy of Keratin + Macadamia in Professional Formulations

The combination of hydrolysed keratin + macadamia oil is today considered a standard in high-end reconstructive formulations. Keratin acts from within by rebuilding the protein matrix, while macadamia oil acts from outside by sealing the cuticle and delivering immediate shine and softness.

Among the professional products that integrate both ingredients optimally, the Reconstructive line from cliCHair is particularly valued by Swiss professionals. The Reconstructive Shampoo and Reconstructive Mask combine hydrolysed keratin and macadamia oil in a reconstructive protocol designed for chemically treated hair. The Intensive Remedy Shampoo also incorporates keratin in its repairing formulation.