Source and Chemical Structure:Amino acid-based surfactants are produced through the condensation reaction of naturally derived fatty acids (such as coconut oil and palm oil) with amino acids (like glutamic acid, glycine, and sarcosine). Their fundamental structure can be represented as:R-CO-NH-CH(R')-COOHAmong them,ROn one end is a long-chain alkyl group (lipophilic tail), and on the other end is the carboxyl group of an amino acid (hydrophilic head). This structure mimics the composition of the skin's own keratin, endowing it with an innate affinity.
Gentleness:The most prominent advantage of amino acid-based surfactants is highlighted in the following aspects, with comparisons to the other two categories:
- pHValue and Skin Barrier:Amino acid surfactant solutions are typically weakly acidic.pH 5.5-6.5), and with healthy skinpHThe value range is a perfect match. Meanwhile, soap base is produced through the saponification of oils and strong alkalis,pHGundam9-10It is strongly alkaline. Using soap-based products can disrupt the skin's natural acidic protective barrier, leading to compromised barrier function, resulting in tightness and dryness. Sulfate-based surfactants (such asSLSare mostly neutral or slightly alkaline.
- Irritation:Amino acid surfactants have larger hydrophilic heads and contain amide bonds, which result in the formation of larger micelles with higher aggregation numbers in solution. This makes them less likely to penetrate the healthy stratum corneum of the skin, leading to significantly lower irritation rates to the eyes and skin compared to sulfate-based surfactants.SLS/SLESDue to its strong degreasing ability and small molecular structure, it is considered to be highly irritating to the skin and eyes.
- Skin feel:Amino acid-based surfactants leave the skin feeling refreshed and non-tight after washing, whereas soap-based cleansers and...SLSOften shows noticeable effects after use."Scrubbing the plate"Dryness.
Biodegradability:Due to their primary structure originating from natural plants and animals, amino acid-based surfactants can be rapidly and thoroughly decomposed by microorganisms in the environment into carbon dioxide, water, and inorganic salts. The final products are harmless to the environment, aligning with the principles of green chemistry. Soap-based surfactants are also biodegradable, but sulfate-based surfactants degrade at a relatively slower rate.
In summary, amino acid-based surfactants, with their natural origin, mild acidity, low irritation, comfortable post-wash feel, and excellent biodegradability, comprehensively outperform soap-based and sulfate surfactants in terms of gentleness. They are particularly suitable for sensitive skin, infant skincare products, and high-end facial cleansers.