The Development of the Moisturiser

Even though cosmetics have most certainly existed for much longer, the first evidence of cosmetics dates from about 6000 years ago in Ancient Egypt. Aloe, myrrh, and frankincense are common among Egyptians. Ancient Egyptians believed these products, particularly frankincense, had anti-aging properties and used them as anti-wrinkle creams. Jain et al. (2009) also reported that men and women in Egypt used scented oils and ointments to clean and smooth their skin and mask body odor as early as 10,000 BC. Egyptian hygiene and wellbeing were inextricably linked to cosmetics. For protection against the hot sun and dry winds, oils and creams were used. Egyptian customs were exported and utilised by Greeks and Roman

.

Crocodile excrement, white lead and chalk were commonly used by ladies to enhance the appearance of their skin. They also made face masks out of starch and eggs, which were thought to tighten the skin, reduce wrinkles, and keep the face looking youthful. The term “cosmetic” comes from the Greek word “kosmetos,” which means “adornment” or “ornament.” Ointments containing cypress, cedar, and incense resins were applied at night. Lead acetate (white lead) and cinnabar were used to treat the skin.

After the conquest of Carthage, figs (Ficus Carica L.) became very common in Rome. In order to formulate facial cream, they were combined with banana (Musa L.), oats (Avena L.), and rose water. Galen is credited with inventing the Frigus Crepito, a precursor to the present cold cream. It is used as a skin protector, comprising almond oil, rose water and beeswax. Gels and salves were used to blanch skin in China, especially during the Shang Dynasty (1760BC). New fixings and techniques were developed and presented as skincare moved to Europe and the Middle East.

The first virus cream was made with rose oil and water, with beeswax liquefied into it. Scabs were treated with the mineral alum, and skin inflammation was treated with olive lead. Creams, also known as topical formulations, have been a staple in cosmetics since ancient civilizations. Creams are cosmetic or pharmaceutical products based on the techniques applied. Unmedicated creams are widely used in a number of dermatological conditions. In ancient times, creams were simply made through the combination of two or more ingredients with water as a solvent. Albert Kligman coined the term “cosmeceuticals” (a mixture of “cosmetics” and “pharmaceuticals”) in 1984 to provide an expert description of products with both cosmetic and therapeutic value. Newer approaches for cream formulation are being used as technology advances; hence, the cosmetics industry today is very different from the one described earlier.

Surprisingly, there is no agreement about what constitutes a moisturiser, despite having a deep history. The word is a neologism invented by Madison Avenue advertisers to promote the simplistic notion that they moisturize the skin. The inclination to add oily materials to the skin is almost instinctive, and it can date back to the dawn of time. Natural substances, such as honey, oils or lipids, and fiber have been used in topical treatments to heal wounds since the ancient Egyptians. Moisturisers were once thought to prevent transepidermal water loss (TEWL) by occlusion, preventing dryness, in addition to skin smoothness and elasticity maintenance.

The bricks and mortar model suggests that the stratum corneum (SC), while being a dead layer, functions as an active membrane. Corneocytes are the bricks, with their tough cell membranes and keratin microfibrils, while the lipid layers between the cells are the mortar. The loss of the predominant intercellular lipids that play a vital role in regulating skin humidity by forming bilayers, such as ceramides, cholesterol, and fatty acids, results in damage to the structure of the water barrier, resulting in dry skin. When the moisture content of the skin falls below 10% and the SC loses its continuity, it is considered dry.

Emulsifiers, moisturising agents, polymer/thickeners, sensory modifiers, and preservatives are among the ingredients used in commercially available moisturisers. Humectants, occlusives, and emollients are the three main types of moisturising ingredients. In addition to such ingredients, advanced benefit ingredients including vitamins, antioxidants, lipids, or sunscreens are often included in the formulation of moisturisers

Humectants draw and bind water due to their chemical nature, making them hygroscopic conditioning agents, that will most likely pull water from the deeper epidermis and dermis. Humectants are not easily retained on the skin by wash-off items, such as cleansers even though they are important moisturising ingredients in leave-on formulas. Despite that, they are still recommended to be used as leave-on products, especially humectants with a prolonged TEWL impact and the application should be at least twice a day or more based on skin dryness severity. Ingredients that exhibit humectant properties are glycerin, lactic acid, panthenol, butylene glycol, propylene glycol, sodium pyrrolidone carboxylic acid (PCA) and urea.

Occlusive agents help maintain a moisturized state in the stratum corneum (SC) by avoiding excessive water loss from the skin’s surface. The increased water content has the effect of speeding up barrier recovery. Since most occlusive agents lack hydroxy functional groups in their chemical structure, they are unable to bind to water. They can, however, efficiently seal moisture into skin as they can form uniform hydrophobic films. Ingredients that exhibit occlusive properties include petrolatum, lanolin, mineral oils and silicone derivatives. Petrolatum, also known as petroleum jelly, is the most popular occlusive.

Emollients are water-insoluble materials, such as oils and lipids that do not form an occlusive film. The molecular weight of the substance may often distinguish an emollient from an occlusive. They are often utilised because of their ability to smooth and soften skin and give it a silky texture. They are mostly made up of lipids that are close to the skin’s intercellular lipids, and they can possibly replenish the lipid matrix that is damaged. By substituting the main lipid components, the moisturisers’ combinations of ceramide, fatty acids and cholesterol can help fix lipid bilayers damaged by solvents, soaps and harsh dry or cold weather conditions. Ingredients that exhibit emollient properties include Cetylcaprylic/Capric Triglyceride, Cetearyl or Cetyl Alcohol, or oils, such as soybean, sunflower seed and grapeseed oil

Emulsifiers are necessary for the stability of moisturisers. Moisturisers are generally formulated either as emulsions or kinetically stabilised colloidal suspensions of two immiscible liquids.

Niacinamide (Vitamin B3) is an inactive ingredient included in moisturisers that is the water-soluble physiologically active form of vitamin B3 used in many moisturisers and has a range of dermatological therapeutic benefits. Niacinamide boosts ceramide production, decreases hyperpigmentation, has anti-inflammatory and antibacterial properties, and aids in anti-aging. Flushing is a possible side effect of niacinamide-containing products. The offender ingredient is niacin, a form of vitamin B3 that can show up as a contaminant if raw material quality is not monitored properly!

Alpha hydroxy acids (AHAs), an additional ingredient in moisturizers, are commonly referred to as “fruit acids”. They are a group of substances containing organic carboxylic compounds that include citric acid, glycolic acid, malic acid, lactic acid, and tartaric acid, all of which are naturally derived .AHAs are available at lower concentrations ranging from 5 to 10% that can be used on a daily basis to improve barrier function and improve the skin appearance related to wrinkling, sun damage and hyperpigmentation. Meanwhile, higher concentrations ranging from 20 to 70% are used as chemical peels.

Antioxidants, such as vitamins C (Ascorbic Acid) and E (α -tocopherol) are effective for protecting the skin from oxidative stress from the environment, such as UV rays and emissions. However, when exposed to sunlight, they become unstable. There are more stable types of these vitamins available, such as vitamin E acetate and Magnesium Ascorbyl Phosphate. However, inside the skin, these must be absorbed and transformed into the active form. Since Tartaric Acid, Citric Acid, Ethylenediaminetetraacetic Acid, and its salts have minimal antioxidant activity, they serve as chelating agents, enhancing the effectiveness of antioxidants by reacting with heavy metal ions.

Hyaluronic acid (HA), a disaccharide polymer, is an essential part of the extracellular matrix, which helps keratinocytes proliferate, migrate, and heal wounds. Due to its various hydroxyl moieties, HA is extremely hygroscopic and is frequently touted as a skincare wonder ingredient. Because of its high molecular weight, topically-applied HA is unable to penetrate deeply enough into the skin to exert its biological effects

Preservatives are used to kill or inhibit microorganism growth that is accidentally introduced during manufacturing or use. Pathogens and nonpathogens are also possible contaminants. The ideal preservative should have a wide spectrum of activity, be stable in the product, safe to use and have no effect on the product’s physical properties. Since no single preservative can satisfy all of these criteria, a mixture of substances is commonly used. Ingredients that are widely used as preservatives in moisturisers include parabens (methyl-, propyl-, ethyl- and butyl-paraben) and phenoxyethanol.

Previous research has suggested that parabens can pose serious health risks, especially to humans. As a result, there is an increasing market for preservative-free cosmetics. Natural compounds, such as plant extracts or essential oils, may be used to replace parabens and address the issue of microbial purity in cosmetics. Parabens are a form of preservative that easily penetrates the skin and is suspected of interfering with hormone function, resulting in endocrine disruption. They interrupt male reproductive functions besides having the ability to mimic estrogens, the female sex hormones.

According to several studies, when methylparaben is applied to the skin, it will interact with other chemicals, causing skin aging and damage to DNA. However, when consumed, parabens in food are metabolized, making them less estrogenic. Meanwhile, parabens in cosmetics are applied directly to the skin and absorbed into the body. They then bypass the metabolic process, entering the bloodstream and body organs intact. They have been linked to cancer and neurotoxicity among other health issues'

In order to resist contamination and microbial growth, products without preservatives added have to depend on low water activity, such as high alcohol concentration, low pH, and/or other agents that are not considered preservatives, such as essential oils. However, other types of inconveniences can result from such formulations, such as insufficient preservation, poor cosmetic properties, or the risk of other adverse reactions. When an allergy reaction is suspected, substances, such as Ethylhexylglycerin and Caprylyl Glycol are normally used to replace preservatives.

Sunscreens are also included in moisturiser formulations due to media coverage provided on carcinogenicity and the accelerated skin-aging effects of sunlight. The utilisation of sunscreen products has increasingly widened not only in sunscreens but also in other cosmetics, such as moisturisers, where they can cause photocontact and contact allergic reactions. Certain antioxidants, such as Retinol Palmitate, Tocopherol (vitamin E) Acetate and Ascorbic Acid (vitamin C), are utilised more specifically in sunscreen and moisturising products to avoid aging

Moisturisers are often used for both healthy and diseased skin, bridging the gap between medicine and consumer goods. The ability to tailor particular agents to specific dermatological needs will be critical in the future of moisturiser therapy. Knowing the characteristics and interactions of active ingredients with the skin will allow for better utilisation of available moisturisers. It is important to keep in mind that moisturiser formulas do not come without flaws. Those who apply moisturisers on a regular basis can develop contact dermatitis, which is often caused by preservatives or fragrances used in many commercial products. The message, therefore, is always to visit your chosen skincare professional or Dermatologist to be sure what you use, is right for you.

The above is taken from:

Mawazi, S.M.; Ann, J.; Othman, N.; Khan, J.; Alolayan, S.O.; Al thagfan, S.S.; Kaleemullah, M. A Review of Moisturizers; History, Preparation, Characterization and Applications. Cosmetics 2022, 9, 61. https://doi.org/10.3390/cosmetics9030061

Department of Pharmaceutics, School of Pharmacy, Management and Science University, Shah Alam 40100, Malaysia

Department of Clinical and Hospital Pharmacy, College of Pharmacy, Taibah University, Al-Madinah Al-Munawwarah 30001, Saudi Arabia

Department of Clinical Pharmacy, School of Pharmacy, Management and Science University, Shah Alam 40100, Malaysia

The main article goes into greater depth on the subject please follow the link to read in full.