Hair alteration, such as the process achieved with a product like Ion 7NA, is fundamentally a chemical modification of the hair fiber’s internal composition and external surface. Achieving a new shade requires manipulating the structural proteins and natural pigments housed deep within the hair strand. Understanding this transformation requires focusing on the molecular changes that allow the color to be deposited and retained. This process temporarily shifts the chemical balance of the hair to achieve the desired cosmetic effect.
Hair Structure and Natural Pigment
The natural state of the hair fiber is defined by its three main layers and its inherent chemical composition. The outermost layer is the cuticle, which consists of transparent, overlapping keratin scales that lie flat, protecting the inner structure and providing smoothness. Beneath this protective shield lies the cortex, the core of the hair strand, which is composed of fibrous protein chains called keratin. These keratin proteins are rich in the sulfur-containing amino acid cysteine, which forms strong chemical cross-links known as disulfide bonds, giving hair its structural integrity and strength.
Natural color is determined by melanin pigments dispersed throughout the cortex. Two primary types exist: eumelanin, which is responsible for brown and black shades, and pheomelanin, which provides the warmer, lighter tones of red and yellow. The unique combination and concentration of these two pigments create an individual’s specific natural hair color. For a product like Ion 7NA to successfully deposit its medium ash blonde pigment, it must chemically bypass the cuticle and interact directly with the cortex where the natural melanin resides.
The Chemical Process of Color Alteration
The demi-permanent formulation of Ion 7NA initiates the alteration process using an alkaline agent, often ethanolamine, instead of ammonia. This alkaline component raises the hair’s natural acidic pH (approximately 4.5 to 5.5) up to an alkaline range, typically 8 to 10. The rise in alkalinity causes the outer cuticle scales to swell and lift slightly, creating microscopic pathways into the cortex. This allows the dye components to penetrate the hair shaft.
Once inside the cortex, the dye precursors (small, uncolored molecules) begin to react with a low-volume oxidizing agent, such as a 10-volume hydrogen peroxide developer. This oxidative reaction causes the precursor molecules to link together and polymerize, forming large, colored molecules. These newly formed molecules are too large to escape the hair structure, effectively trapping the new pigment inside the cortex. Since Ion 7NA is a deposit-only color, the process minimizes the oxidation and breakdown of natural melanin, ensuring the hair’s natural color is largely preserved underneath the new tone.
Post-Treatment Changes to Hair Integrity
The chemical process required for color deposition inevitably causes a temporary shift in the hair fiber’s physical and chemical integrity. The forced opening of the cuticle, necessary for the dye to enter, leaves the outer layer in a more raised and disordered state. This physical damage results in increased porosity, meaning the hair absorbs and loses moisture much more rapidly.
The prolonged exposure to the alkaline environment also disrupts the hair’s natural acid mantle. This pH shift from acidic to alkaline can compromise the structural proteins, leading to a reduction in tensile strength and elasticity.
The compromised cuticle layer is less effective at protecting the cortex, which allows for faster fading of the cosmetic color and makes the fiber more vulnerable to mechanical stress. This vulnerability manifests as increased friction, tangling, and a higher risk of breakage, especially when the hair is wet.
Maintaining Chemical Balance After Treatment
Restoring the hair’s chemical equilibrium is the primary focus of post-treatment care. The initial step is to re-acidify the hair fiber using specialized acidic shampoos or treatments. These products, formulated to have a pH between 3.5 and 4.5, help to contract and flatten the outer cuticle scales. Closing the cuticle is crucial for locking the polymerized dye molecules inside the cortex and minimizing color leaching.
After the cuticle is sealed, the focus shifts to repairing internal damage and replenishing lost material. Utilizing treatments rich in proteins or amino acids can temporarily patch structural weaknesses within the cortex. Lipid-rich conditioners and masks help restore the hydrophobic layer on the hair’s surface, improving shine and reducing moisture loss. By maintaining an acidic environment and supplying restorative components, the altered hair fiber can better resist environmental damage and retain the shade.