The Reality of High-Concentration PPT and Formulation Design in Amprem, I-ne's New Hair Care Line

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Looking at the ingredient lists for Amprem's shampoo and treatment, the ingredient listed immediately after water is "hydrolyzed keratin water (wool)" in Keratin Shot and "silk water" in Silk Shot. In typical shampoos, water is usually followed by surfactants or humectants (such as glycerin), so a formulation in which an ingredient whose name falls under hair-repair ingredients sits in second place is unusual.

However, the "hydrolyzed keratin water" and "silk water" used here are not the same as the powdered hydrolyzed keratin or hydrolyzed silk that have been widely used as repair ingredients in conventional hair care products. These are ingredients obtained by steam-distilling hydrolyzed keratin or silk. They are made by a process similar to that of aromatic distillates used in cosmetics, such as damask rose flower water, and the vast majority of their actual composition (an estimated 99% or more) is thought to be water.

For this reason, it would not be accurate to regard this ingredient on its own as meaning that "the repair ingredient itself is formulated at an ultra-high concentration." On the other hand, there is a strong possibility that the distillate contains amino acids and other substances into which the raw material has been further broken down during steam distillation, so compared with plain purified water, it can be expected to play a supporting role in hair repair. Replacing part of the main ingredient, water, with this kind of PPT distillate appears to be intended to create a moisturizing and repairing environment at the base level.

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The feature highlighted as Amprem's biggest selling point is its formulation ratio of "over 6,800 times the keratin" and "over 6,900 times the silk" compared with I-ne's previous products. It is easy to suspect that the distillates mentioned above, such as "hydrolyzed keratin water," are being counted to inflate the multiplier, but according to the note on the back of the product and confirmation with the manufacturer, these figures are comparisons of the pure hair-repair ingredients "hydrolyzed keratin (wool)" and "hydrolyzed silk" alone, excluding the distillates.

Furthermore, the hydrolyzed keratin (wool) and hydrolyzed silk used are both standardized as medium-molecular-weight PPT with a molecular weight of approximately 1,000.

• Hydrolyzed keratin (wool): A wool-derived protein with an amino acid composition similar to that of human hair, well suited to repairing accumulated damage and adding body and firmness.
• Hydrolyzed silk: Rich in fibroin, the main component of silk thread, it adsorbs onto the hair surface to impart smoothness and shine.

PPT ingredients broadly fall into low-molecular-weight types that penetrate deep into the hair and high-molecular-weight types that coat and protect the surface, but medium-molecular-weight PPT of around 1,000 can provide a good balance of both penetration and surface adsorption. A clear feature of this formulation is that the amount of the repair ingredients themselves has been raised substantially compared with the company's previous products.

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The cleansing base that forms the backbone of the shampoo is a low-irritation design intended for heavily damaged hair in both Keratin Shot and Silk Shot.

The base combines the amphoteric surfactant cocamidopropyl betaine with the amino acid-based cleansing agent sodium lauroyl hydroxyethyl-β-alanine to ensure a mild lather. Added to this are PPT-based surfactants that provide repairing action while cleansing (potassium cocoyl hydrolyzed keratin on the keratin side and sodium lauroyl hydrolyzed silk on the silk side).

As a supplementary cleansing agent, both contain sodium laureth-4 carboxylate, a so-called weakly acidic soap-type surfactant, which helps with rinsing and provides moderate cleansing power. As for the subtle differences between the two types, Keratin Shot adds a taurate-based surfactant (sodium methyl cocoyl taurate) for a slightly more thorough clean, while Silk Shot uses an amphoteric surfactant (sodium cocoamphoacetate) for gentler degreasing.

In addition, as ingredients to control frizz and waviness, Keratin Shot contains levulinic acid, and Silk Shot contains diammonium aminoethyl thiosuccinate (commonly known as Tostea). Both also include meadowfoam-δ-lactone, a heat-protection ingredient that uses the heat from hair dryers and irons to protect and repair hair, as well as meadowfoam seed oil and nine amino acids.

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Hair consists of three layers: from the outside in, the cuticle, the cortex, and the medulla. The cuticles covering the surface are bound together by a lipid layer called the CMC (cell membrane complex), which functions as a barrier preventing substances from entering from the outside.

In recent years, it has become known that a "cuticle barrier membrane" exists in the deepest part of the cuticle, that is, at the boundary with the cortex, and it is said that repair ingredients must pass through this membrane in order to reach deep inside the hair. Amprem adopts a high-penetration, close-adhesion formulation designed to penetrate as far as this barrier membrane, with the aim of efficiently delivering the high-concentration PPT and various repair ingredients into the hair.

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In the treatment as well, hydrolyzed keratin water and silk water are used as the base liquid. In addition, the PPT concentration is set higher than in the shampoo, with formulation ratios of over 7,200 times for keratin and over 7,300 times for silk compared with previous products.

A notable structural element is the choice of conditioning base (cationic surfactant). Typical hair treatments and previous I-ne products have largely used "quaternary ammonium salts" (such as steartrimonium chloride) as the main agent; these have a strong softening effect but are relatively irritating to the skin. In this product, however, "tertiary amines" (behenamidopropyl dimethylamine and stearamidopropyl dimethylamine), which are extremely gentle on the skin, have been adopted as the main agent.

Tertiary amines are low-irritation but tend to have a milder softening effect; this product compensates for the texture by combining them with pseudo-cationic ingredients and the like. A formulation that centers on a cationic base mindful of irritation, despite being specialized for damage care, is rare among mass-market products.

As for the base oil composition, Keratin Shot is a somewhat lighter design based mainly on cetearyl alcohol combined with dimethicone, while Silk Shot is a dimethicone-based design that emphasizes a silky-smooth feel.

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In tests using 100% human hair extensions, both types produced a rich, creamy lather and a mild wash with no squeaky feeling. The cleansing power is gentle enough that pre-rinsing or washing twice is recommended when using wax or hard styling products. During rinsing, the hair has a distinctive slippery, supple feel.

The treatment has a substantial, somewhat firm texture, but it blends into the hair smoothly. Treatments using tertiary amines generally can take some time before the hair softens, but this product penetrated quickly right after application, and the hair could be felt loosening up.

• Keratin Shot: Rather than straightening out the hair's natural kinks, it adds firm body and bounce to each strand, producing a moderate sense of ridge (elasticity and cohesion). It is suited to those who want more volume or want to bring out the waves of a permed style.
• Silk Shot: The finish emphasizes straightness, with standout surface shine and smoothness. Because it leaves the hair light to run fingers through with a silky-smooth texture, it is well suited to long hair and hair prone to frizz.

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Amprem is a hair care line that does not rely solely on the PPT distillate used in its base, but instead contains medium-molecular-weight hydrolyzed keratin and hydrolyzed silk themselves at high concentrations several thousand times those of previous products. Its real distinguishing feature can be said to be that, by combining a low-irritation conditioning design centered on tertiary amines with a penetration technology focused on the cuticle barrier membrane, it brings an ingredient composition close to that of salon-exclusive products into a mass-market price range (¥1,980 including tax for a 420 mL bottle). The series offers a clear choice based on hair type and preferred texture: Keratin Shot if you want body and firmness, and Silk Shot if you want shine and smoothness when running your fingers through your hair.