Introduction

With growing emphasis on skin health, gentle skincare has become an enduring topic. As the first line of defense for external beauty and a direct reflection of physical health, skin care now prioritizes natural, healthy, and mild approaches to minimize irritation from chemical components. ​Tromethamine​ (TRIS), a vital neutralizing agent, reacts with acidic ingredients in cosmetic formulations via its amino group to form water-soluble salts. This not only enhances polymer solubility but also improves product stability and rheological properties, making it particularly recommended for ​sensitive skin.

Physicochemical Properties

Tromethamine, chemically known as ​Tris(hydroxymethyl)aminomethane​ (abbreviated as ​TRIS), is a critical pH buffer widely used in chemical engineering, cosmetics, and biomedical fields.

Advantages in Cosmetic Applications

Alkaline agents have long been used in cosmetic formulations. Modern chemists often seek ​ideal neutralizing agents​ for emulsions and gels. While triethanolamine (the most common choice) or alkali metals (e.g., NaOH, KOH) are frequently used, they face criticism for safety concerns, pH drift, or film-forming issues. In contrast, tromethamine demonstrates superior performance:

Key Literature Highlights

Kumtornrut C, Manabe S D, Navapongsiri M, et al. A cleanser formulated with Tris (hydroxymethyl) aminomethane and l‐arginine significantly improves facial acne in male Thai subjects[J]. Journal of Cosmetic Dermatology, 2020, 19(4): 901-909.

Background Introduction

Research Methods

Research Results

Conclusion

Literature on Safety Investigation

Tromethamine A P. Safety Assessment of Tromethamine, Aminomethyl Propanediol, and Aminoethyl Propanediol as Used in Cosmetics [J].

Background Introduction

The Cosmetic Ingredient Review (CIR) Expert Panel is an independent expert organization tasked with scientifically evaluating the safety of cosmetic ingredients and providing transparent and open review results.

Research Purpose

To assess the safety of three commonly used ingredients in cosmetics: Tromethamine (Tromethamine), Aminomethyl Propanediol, and Aminoethyl Propanediol. These ingredients are widely used in cosmetics for various functions, including as pH regulators and fragrance components.

Safety Assessment Results for Tromethamine

Conclusion

Tromethamine is considered safe under current cosmetic use practices and concentrations, providing scientific support for its use in gentle skincare products.

Typical Patent Analysis

US005124078A: Ultra-Gentle Body Wash or Shampoo Formulation

The patent specifically mentions the use of tromethamine as a neutralizing agent, particularly for neutralizing alkyl polyethylene glycol ether carboxylates. This neutralization process helps form stable surfactant combinations, which is crucial for preparing gentle body washes and shampoos. Tromethamine is also used to adjust the pH of the product to ensure it remains within a gentle pH range, typically 6.5-6.8. This helps reduce skin irritation because the natural pH of the skin is approximately 4.5 to 6.0, and deviations from this range can lead to skin dryness and irritation.

US20230210737A1: Aqueous Solution for Dissolving Salicylic Acid, Method for Preparing It, and Cosmetic Composition Containing It

Tromethamine improves the hydrophilicity of salicylic acid by forming salts with it, allowing better dissolution and dispersion in water-based cosmetics. This salt formation also helps reduce the crystallization tendency of salicylic acid, thereby maintaining the stability of cosmetic formulations under different temperature conditions. Additionally, the addition of tromethamine helps reduce the dependence of cosmetic formulations on solvents such as ethanol, thereby reducing potential skin irritation.

US6426065B1: Application of Tris(hydroxymethyl)aminomethane in the Process of Cold Permanent Waves

In this patent, tromethamine serves as the main component in the cold wave perm process, aiming to improve the permanence and efficiency of cold perms. As an alkalizing agent, tromethamine (with a pKa value of about 8.06) provides about 22% free amine in a formula with a pH of about 7.5, which is more effective than monoethanolamine. Tromethamine increases the diffusion of amines into the hair, providing more reaction sites and enhancing the reaction between amines and reducing agents, offering better pH buffering levels, which is crucial for maintaining hair integrity and reducing damage during the cold wave perm process.

EP3925671A1: Cosmetic Raw Materials, Cosmetics, and Methods for Producing Cosmetics

In this patent, tromethamine acts as the cationic part of an organic ammonium salt, with hydrogen bonding functional groups capable of forming hydrogen bonds with polar groups on the skin and hair, which can improve the moisturizing properties and skin affinity of cosmetics.

US5650143: Deodorant Cosmetic Ingredients

In this patent, tromethamine is used as a component of a deodorant cosmetic stick to provide stability and transparency, while also acting as an antibacterial agent by preventing bacteria from producing malodorous degradation products, thus exerting a deodorizing effect.

US8080581B2: Cosmetics

In this patent, tromethamine is used as a cosmetic ingredient with antioxidant activity and moisturizing properties, as well as excellent emulsifying and dissolving capabilities, which can significantly reduce the greasy feeling on the skin.

US10039701B2: Compositions for Treating and Caring for Skin, Mucous Membranes, Scalp, and for Use in Cosmetics or Medicines

In this patent, the hair dye uses the alkaline properties of tromethamine to help open the cuticle layer of the hair, allowing dye molecules to penetrate and color the cortex layer of the hair. Tromethamine, as an alkaline agent, helps increase the pH of the hair dye, thereby activating the reaction of oxidizing dyes (main intermediates and color couplers) with hair keratin, achieving a lasting coloring effect. At the same time, tromethamine helps improve the stability and performance of the hair dye, ensuring good performance during storage and use.

US11229586B2: Surfactant-Free Cosmetic Composition

In this patent, tromethamine acts as a humectant to help maintain skin moisture, maintain water-oil stability without surfactants, and reduce skin irritation and potential allergic reactions.

US11260007B2: Cosmetic Composition Containing Particles with High Content of Ceramides and Method for Preparing the Same

By neutralizing the acidic components in the formulation, tromethamine helps stabilize ceramide particles, preventing precipitation in cosmetic formulations. This stable particle structure helps improve skin absorption of ceramides, thereby enhancing skin barrier function and providing better moisturizing and repairing effects.

Conclusion

Tromethamine (TRIS) offers unprecedented gentle experience for sensitive skin with its outstanding pH buffering capacity. It not only stabilizes cosmetic formulations, enhances polymer solubility, and reduces skin irritation but also significantly improves acne, reduces sebum secretion, and minimizes pore size, providing comprehensive skin improvement and true gentle care. Hubei Grand Fuchi Pharmaceutical and Chemical Co., Ltd. adopts industry-leading continuous fixed-bed production technology to ensure the high purity and extreme batch-to-batch quality uniformity of tromethamine, providing the purest protection for your skin.