Hydration is a key aspect of skin care. In moisturized skin, renewal and regeneration processes occur naturally, while signs of sensitivity and irritation appear less frequently. Such skin looks healthy, radiant, less prone to age-related changes.
When choosing moisturizers and procedures, it is important to consider several aspects:
- To ensure a sufficient level of skin hydration, it is not enough to simply attract water to the tissues – it is also necessary to retain it and prevent transepidermal moisture loss. The water balance of the body as a whole is also important.
- Dry skin type is a genetically determined condition in which the number of sebaceous glands and their activity are reduced. Dry skin is not corrected by moisturizers. Such skin needs not only hydration but also protection from external factors and restoration of the lipid barrier.
At the same time, under the influence of external and internal factors, any skin – dry, normal, combination or oily – can become dehydrated.
The main signs of skin dehydration are: dryness and peeling; tightness; loss of healthy shine; decreased elasticity; increased sensitivity; slower healing of microtraumas.
The causes of skin dehydration can be:
- Damage of the water-lipid barrier;
- Deficiency of natural moisturizing factor (NMF) components and intercellular components of the dermis;
- Insufficient consumption of water and nutrients;
- Influence of the external environment (temperature changes, wind, sun);
- Age-related skin changes;
- Hormonal imbalance;
- Dermatoses of various etiologies;
- Taking medications (diuretics, systemic retinoids);
- Bad habits.
Thus, proper hydration is necessary for any skin, regardless of its type and age, at any time of the year. That is why most serums, creams, and masks by Reneo Cosmetics contain moisturizing ingredients.
Main types of moisturizing ingredients
Modern moisturizing skin care products often combine ingredients with different mechanisms of action, which allows achieving optimal results in each specific case, taking into account the patient’s clinical picture.
According to their mechanism of action, the following types of moisturizing ingredients can be distinguished:
Humectants
Humectants are hygroscopic substances that can attract water from the environment and retain it in the outer layer of the epidermis for a longer period of time. They can bind water in the skin and prevent its loss. Humectants draw water from the deeper layers – the viable epidermis and dermis – but can also absorb moisture from the environment if the humidity level exceeds 70%. Some of these substances, such as urea, are endogenous and are part of the natural moisturizing factor (NMF). Humectants also include, for example, honey, sorbitol, glycerin, panthenol, hyaluronic acid, allantoin, AHA acids (glycolic acid, lactic acid, sodium pyrrolidone carboxylate, carboxylic acid), propylene glycol, butylene glycol, etc. Humectants are key moisturizing ingredients in leave-on formats of cosmetics.
Occlusives
Occlusives are components that create a protective film on the skin surface and prevent transepidermal moisture loss (TEWL). They mimic the lipid barrier, thereby reducing the impact of negative environmental factors. Such a barrier allows for the replenishment of water content in the stratum corneum. Most occlusives do not contain hydroxyl functional groups in their chemical structure, so they cannot bind water. However, since occlusives form homogeneous hydrophobic films, they effectively “seal” moisture in the skin. The most highly occlusive component is considered to be petrolatum. Also included in this group of humectants are liquid paraffin, lanolin, squalene, mineral oils and silicones (dimethicone), etc.
Emollients
Emollients are water-insoluble components that are mainly composed of lipids that are similar to the intercellular lipids of the skin. They can restore the damaged lipid matrix. Replacing the main lipid components, combinations of humectants with ceramides, fatty acids and cholesterol can help restore lipid bilayers damaged by solvents, detergents and harsh dry or cold weather conditions. Emollients do not form an occlusive film, but fill the gaps between corneocytes, improving the water balance of the skin, its softness, smoothness, elasticity. Such substances include cetylcaprylic/capric triglyceride, cetearyl or cetyl alcohol, oils (e.g., soybean, sunflower, grape, avocado oil, jojoba oil, sweet almond oil), etc.
It is worth noting that some substances can exhibit the properties of several groups at once. At the same time, each group of moisturizing components has its own disadvantages.
Many humectants also have emollient properties. On the other hand, humectants can increase transepidermal moisture loss due to increased absorption of water from the dermis into the epidermis, where it quickly evaporates. Therefore, it is often advisable to combine humectants with occlusive agents.
Some occlusives form too dense a barrier film on the skin surface, which disrupts natural oxygen exchange. Such substances can have high comedogenicity, clog pores and provoke allergic reactions. Therefore, it is better to give preference to components that are close in composition to human sebum. For oily and sensitive skin, it is worth choosing moisturizers with a minimum content of occlusive components.
Comedogenicity is also the main disadvantage of emollients, since most of them are represented by lipids. However, this drawback can be easily eliminated by careful selection of components according to the needs of the skin.
Given these features, cosmetic formulas most often combine moisturizing components with different mechanisms of action, which ensures their maximum effectiveness.
What moisturizing components are most often used in professional cosmetics?
One of the most important aspects of ensuring tissue hydration is the replenishment of the components of the natural moisturizing factor (NMF) of the skin. Therefore, the most common moisturizing components in professional cosmetics are NMF components: amino acids, lactic acid, urea, polysaccharides (hyaluronic acid, glycerin).
- Arginine amino acid – improves microcirculation, stimulates collagen synthesis, retains water molecules, provides antioxidant protection.
- Lactic acid in concentrations up to 10% has moisturizing properties, stimulates cell renewal, maintains optimal skin pH balance.
- Urea has hygroscopic and keratolytic properties, improves skin barrier function and reduces TEWL in patients with atopy.
- Hyaluronic acid – a hygroscopic substance that attracts and retains moisture, creates a gel environment around cells. High-molecular hyaluronic acid acts on the surface of the skin, fills wrinkles, provides instant results and a WOW-effect of hydration immediately after application. And low-molecular acid penetrates into the deeper layers of the skin and retains moisture in the tissues for a long time with regular use, providing a prolonged cumulative effect.
- Glycerin – although classified as a humectant, it also performs a number of other functions not directly related to hydration.
In addition to the components of the NMF, moisturizing formulas often include components that are part of sebum, or are close to it in composition.
- One of the main components of sebum is squalene, which serves as a kind of trap for free radicals, protecting the skin from lipid peroxidation under the influence of ultraviolet and ionizing radiation. The production of squalene in the body declines rapidly after 30 years, which contributes to the development of dry skin. Squalane is a saturated form of squalene, in which hydrogenation has removed the double bonds, which makes it more resistant to oxidation and an effective moisturizing agent.
- Jojoba essential waxes are similar in composition to sebum. Jojoba oil forms a semi-permeable lipid layer on the surface of the skin, which effectively protects and moisturizes it.
In addition to jojoba, many plant and natural oils are valuable emollients that not only moisturize, but also have antioxidant properties. For example, avocado oil, sweet almond oil, shea butter.
Plant extracts are also often used as moisturizing ingredients in cosmetics.
- Aloe vera contains vitamins, minerals, essential amino acids and polysaccharides. Due to such a rich composition, it has numerous cosmetic properties: anti-inflammatory, antimicrobial, healing, cooling, moisturizing, soothing and regenerating. Due to the light texture of the juice, this component is suitable for all skin types, including oily and sensitive ones.
- Algae and their derivatives are rich in polysaccharides, which provide their intensive moisturizing and anti-aging properties.
o Brown algae (Laminaria, Fucus, Ascophyllum) are a source of vitamins and minerals and are characterized by an intensive nourishing, moisturizing, detoxifying and strengthening effect. Alginic acid salts are obtained from algae of the Laminaria family – a high-molecular polysaccharide with a high content of hyaluronic acid, which is the basis of alginate masks.
o Red algae contain a high concentration of vitamins, provitamins, minerals (in particular, iodine). In cosmetics, they are used as nourishing, moisturizing and softening agents, as well as to increase lymphatic drainage and brighten the skin. An example is Chondrus Crispus (or Irish moss) and Asparagopsis Armata.
Innovative moisturizing complexes
Modern moisturizers contain not only traditional components, but also specially developed moisturizing complexes that ensure long-term moisture retention in the skin:
- AQUAPRONT – a complex based on hyaluronic acid and barley extract. Able to retain moisture for up to 24 hours. (Conductive Aqua-Booster)
- HYDROVITON24 – contains glycerin, panthenol, lactic acid, urea, amino acids and natural extracts. Provides hydration for 24 hours, strengthens the skin’s barrier functions, increases its antioxidant and protective potential. (Conductive Lift-Booster, Conductive Aqua-Booster)
- AQUAXYL – an innovative complex of two plant saccharides that enhances the activity of aquaporins in the skin, promotes its hydration, stimulates the synthesis of ceramides, strengthens intercellular contacts, improves barrier functions. (Hydra-Help Mask)
- PENTAVITIN® – a plant complex that attracts and retains moisture in tissues, providing deep hydration with an effect of up to 72 hours. (Anti-Red Calming Serum, 3D-Lift Serum)
A comprehensive approach to skin hydration in professional and home care
The variety of moisturizing components provides cosmetologists with ample opportunities to select the right and effective care, taking into account the clinical picture of each patient. In this case, it is advisable to adhere to several simple principles:
- Skin hydration is an essential element of any professional procedure and supportive home care, regardless of age, skin type or aesthetic problem.
- If the aesthetic problem is pronounced, when choosing care products and therapeutic procedures, the main emphasis should be placed on active ingredients aimed at solving this problem. And from the point of view of hydration, preference should be given to components that also have appropriate additional properties (for example, in the treatment of acne – hydration + anti-inflammatory and antibacterial effects; in atopic dermatitis – hydration + restoration of the lipid barrier; age-related changes – hydration + stimulation of collagen and elastin synthesis, etc.).
- When the skin’s hydrobalance is disturbed, a comprehensive approach to hydration is important, taking into account all the main mechanisms of hydration.
In general, to maintain an optimal level of skin hydration, the cosmetologist has the following main tasks:
- Saturating the epidermis with hygroscopic molecules of the natural moisturizing factor.
- Stimulating the skin’s own water reserves to retain moisture in its deep layers.
- Preventing transepidermal moisture loss by restoring the lipid barrier.
- Protecting against harmful environmental factors with sunscreen.
For more information about the natural moisturizing factor, methods and ways to retain moisture in tissues, see the educational video “Natural Mechanisms of Skin Moisturizing.”
References:
Chr.Lee, J.Bajor, T.Moaddel, V.Subramanian, Jian-Ming Lee, D.Marrero, Sh.Rocha, M.D.Tharp. Principles of Moisturizer Product Design. Journal of Drugs in Dermatology. 2019 Jan 1;18(1s):s89-95
S.M.Mawazi, J.Ann, N.Othman, J.Khan, S.O.Alolayan, S.S.Al thagfan, M.Kaleemullah. A Review of Moisturizers; History, Preparation, Characterization and Applications. Cosmetics 2022, 9, 61. https://doi.org/10.3390/cosmetics9030061
Sch.Purnamawati; N.Indrastuti; R.Danarti; T.Saefudin. The Role of Moisturizers in Addressing Various Kinds of Dermatitis: A Review. Clinical Medicine & Research. 2017 Dec; 15(3-4): 75–87. DOI: 10.3121/cmr.2017.1363
Nagrik S U, Shivshankar M., Chharre V S, Dhage S M, Borey V S, Role of aloe vera in skincare: exploring its therapeutic benefits, formulations, and future innovations. Yemen Journal of Medicine 2024;3(3):197-206. https://doi.org/10.18231/j.yjom.2024.021
