Myristyl myristate is an ester derived from myristyl alcohol and myristic acid, commonly used in cosmetic products as an emollient, thickening agent, and skin conditioning agent. It provides a smooth, soft texture to skin and hair care products, enhancing the feel and spreadability of formulations. Myristyl Myristate is especially valued for its ability to improve the moisturizing properties of creams and lotions, and it is often used in products designed for dry or sensitive skin.

Chemical Composition and Structure
Myristyl Myristate is an ester formed by the reaction of myristic acid (a C14 saturated fatty acid) and myristyl alcohol (a C14 fatty alcohol). Its chemical formula is C₂₈H₅₆O₂. The long carbon chains in its structure make it a solid at room temperature and give it strong emollient properties, which help in softening and smoothing the skin by forming a protective barrier.

Physical Properties
Myristyl Myristate appears as a white to off-white, waxy solid at room temperature. It has a melting point between 37°C and 39°C, which allows it to melt easily when applied to the skin, creating a smooth, luxurious feel. It is insoluble in water but soluble in oils and other organic solvents, making it ideal for oil-based formulations.

The name describes the structure of the molecule:

The name "myristyl myristate" is derived from "myristic acid", a type of fatty acid from which it is formed. 

• The "myristyl" part refers to the myristyl group, which is a 14-carbon chain derived from myristic acid. 
• The "myristate" part refers to the ester or salt of myristic acid. The term "myristic" comes from the nutmeg genus Myristica, as myristic acid was first isolated from nutmeg.

Now, let's move on to the natural synthesis process of myristyl myristate. Myristyl myristate is a naturally occurring fatty acid ester found in many plant and animal fats. It is synthesized in cells through esterification, a chemical reaction between an alcohol and a carboxylic acid. In this case, myristic acid (a carboxylic acid) reacts with myristyl alcohol (an alcohol) to form myristyl myristate and water.

As for the chemical synthesis of myristyl myristate, it's a process that involves the reaction of myristic acid with myristyl alcohol in the presence of a catalyst, typically an acid such as sulfuric acid. The reaction can be represented as follows:

Myristic Acid + Myristyl Alcohol ⟶ Myristyl Myristate + Water

The production of Myristyl Myristate involves the esterification of myristic acid with myristyl alcohol. This process results in a stable ester compound that can be used in various formulations. The purity and quality of Myristyl Myristate depend on the control of the esterification reaction and the refining processes that follow.

Description of raw materials used in production

• Myristyl Alcohol - A fatty alcohol with a 14-carbon chain.
• Myristic Acid - A saturated fatty acid with a 14-carbon chain.
• Catalyst - For example, sulfuric acid or sodium hydroxide, used to catalyze the esterification reaction.

Step-by-step summary of its industrial chemical synthesis process. 

• Preparation of Reagents - Myristyl alcohol and myristic acid are prepared or purchased as raw materials.
• Esterification Reaction - Myristyl alcohol is reacted with myristic acid in the presence of a catalyst to form the ester, Myristyl Myristate.
• Neutralization - If an acid is used as a catalyst, the reaction may be followed by a neutralization step, for example with a base.
• Purification - The product is purified to remove impurities and unreacted reagents, e.g., by distillation.

What it is used for and where

Cosmetics

• Skin conditioning agent - Occlusive. This ingredient has the task of modifying the condition of the skin when it is damaged or dry by reducing flaking and restoring elasticity. It has a strong lipophilic character and is identified as an occlusive ingredient; it is generally composed of oily and fatty materials that remain on the skin surface and reduce trans epidermal water loss.
• Skin conditioning agent. Represents the mainstay of topical skin treatment by restoring, increasing, or improving skin tolerance to external factors, including melanocyte tolerance. The most important function of the conditioning agent is to prevent skin dehydration, but the subject is quite complex and involves emollients and humectants.
• Skin conditioning agent - Emollient. Emollients have the characteristic of improving the skin barrier through a source of exogenous lipids that adhere to the skin by improving barrier properties, filling gaps in intercorneocyte clusters to improve hydration by protecting against the onset of inflammation. Basically, they have the ability to create a barrier that prevents transepidermal water loss. Emollients are degreasing or cooling additives that improve the lipid content of the upper layers of the skin by preventing degreasing and drying of the skin. The problem with emollients is that many have a strong lipophilic character and are identified as occlusive ingredients; these are oily, greasy materials that linger on the skin surface and reduce transepidermal water loss. In cosmetics, emollients and moisturizers are often considered synonymous even in the presence of humectants and occlusives.
• Opacifying agent. This additive is included in formulations that may be translucent or transparent to make them opaque and less permeable to light.

Pharmaceuticals

Myristyl myristate can be used in pharmaceutical products. It can act as a vehicle for other ingredients, helping to improve their absorption through the skin. 

It is considered an active pharmaceutical ingredient based on its intrinsic effects (1) and is used as a nanocomposite consisting of clay and lipid carriers prepared by the fusion-emulsion method (2).

Food

Myristyl myristate can be used in some food products as an additive. It can act as an emulsifier, helping to mix ingredients that normally do not mix well together.

Commercial applications 

Emollient. Myristyl Myristate is used in skin care products to soften and smooth the skin.

Skin Conditioning Agent. Used in skin care products to improve the appearance and feel of the skin.

Opacifying Agent. Used in cosmetic formulations to give body and consistency to products.

Emulsifying Agent. Helps to form stable emulsions by mixing water and oils in cosmetic formulations.

Ingredient in Hair Products. Used to condition the hair, making it soft and manageable.

• Molecular Formula    C₂₈H₅₆O₂
• Molecular Weight    424.7 g/mol
• CAS   3234-85-3
• UNII    4042ZC00DY
• EC Number    221-787-9    692-044-8

References_____________________________________________________________________

(1) Muraca G, Ruiz ME, Gambaro RC, Scioli-Montoto S, Sbaraglini ML, Padula G, Cisneros JS, Chain CY, Álvarez VA, Huck-Iriart C, Castro GR, Piñero MB, Marchetto MI, Alba Soto C, Islan GA, Talevi A. Nanostructured lipid carriers containing benznidazole: physicochemical, biopharmaceutical and cellular in vitro studies. Beilstein J Nanotechnol. 2023 Jul 28;14:804-818. doi: 10.3762/bjnano.14.66. PMID: 37533841; PMCID: PMC10390827.

(2) Barbosa RM, Leite AM, García-Villén F, Sánchez-Espejo R, Cerezo P, Viseras C, Faccendini A, Sandri G, Raffin FN, Moura TFALE. Hybrid Lipid/Clay Carrier Systems Containing Annatto Oil for Topical Formulations. Pharmaceutics. 2022 May 17;14(5):1067. doi: 10.3390/pharmaceutics14051067. 

Abstract. Nanocomposites formed by clay and lipid carriers (NLCs) show a high potential for providing controlled release and specific delivery of bioactive molecules and have recently gained attention in the pharmaceutical sector due to their ability to transport hydrophilic and hydrophobic drugs. Recent studies have recognized the biological activity of the oil of Bixa orellana L. (AO) with regards to its healing, antioxidant, antibacterial, and anti-leishmanial properties. Therefore, the purpose of this study is the preparation and characterization of hybrid systems based on lipid nanocarriers and laponite for the delivery of AO. NLCs were prepared by the fusion-emulsification method, using cetyl palmitate (CP) or myristyl myristate (MM), AO, and Poloxamer 188. The morphology, hydrodynamic diameters, zeta potential (ZP), polydispersity index (PDI), thermal analysis, X-ray diffraction analysis (XRD), viscosity behavior, and cytotoxicity testing of the hybrid systems were performed. The thermal study and X-ray diffraction analyses (XRD) revealed polymorphic structural changes compatible with the amorphization of the material. Rheological assays highlighted a typical pseudoplastic behavior in all systems (MM and CP with LAP). The hybrid systems’ morphology, size diameters, and PDIs were similar, preset spherical and monodisperse structures (≈200 nm; <0.3), without significant change up to sixty days. The ZP values differed from each other, becoming higher with increasing AO concentration. XEDS spectra and elemental X-ray maps show peaks of lipids (organic components, C and O) and inorganic components O, Mg, and Si. All samples showed cell viability above 60%. The results indicated a stable, biocompatible hybrid system that can be an alternative for topical application.