Whether in cream, lotion or serum format, moisturizers are designed to increase the hydration of skin. Basically there are three types of ingredients in moisturizers; occlusive, humectant and emollient. Occlusive moisturizers prevent evaporation or transepidermal water loss from the skin by forming a barrier with an emollient ingredient such as mineral oil, beeswax, paraffin, silicones, petrolatum, lanolin, squalane, shea butter or oil like almond or jojoba.
Humectant moisturizers attract water so it can remain on skin surface; water may be pulled from the deeper layers of the skin or from the environment. Humectants include hyaluronic acid, alpha hydroxy acid, sorbitol, glycerin, propylene glycol, urea and sodium lactate. Emollient moisturizers fill in the spaces between skin cells to smooth them out. Ingredients such as lanolin, sodium hyaluronate, glycerine and glyceryl stearate can have occlusive and humectant properties.
Moisturizers treat dry skin by bringing moisture to it. Treat dry skin or wrinkled skin if you want it to look smoother. But if you overuse a moisturizer, pores get clogged and black heads may develop and trapped dead skin cells may dull skin.
Emollients are lubricating ingredients that are critical for making dry skin not feel dry. Emollients include plant oils, mineral oil, shea butter, cocoa butter, petrolatum and cholesterol, as well as animal oils such as emu, mink and lanolin. Ingredients like triglycerides, palmitates and myristates impart an elegant texture and feel.
Retinoids or tretinoin are vitamin A derivatives. They stimulate collagen production, reduce wrinkles and other signs of aging such as brown spots and pore size. They can cause irritation in the form of redness and flakiness. Retinoids make you extremely susceptible to sunburn, therefore daily sunscreen use is an absolute must. Retinoids come in various formulations and strengths depending on skin type.
Exfoliants range from very abrasive, potentially irritating materials such as apricot or walnut kernels and pumice, to gentler exfoliants like jojoba beads, nylon puffs, bath salts and synthetic microbeads. Fine granular particles of these gently scratch the skin surface to remove dead cells. Chemical exfoliants may be broadly divided into five categories: AHA, BHA, enzymes, acne actives and retinoids. AHAs, including citric, glycolic, malic, tartaric and lactic acids, increase skin cell turnover by dissolving the protein bond between cells. In ultrasound, skin exfoliation is called cevitation, where water or gel molecules are driven by the low frequency sound waves to spin rapidly over the skin. This removes dead skin cells safely without inflammation. These ultrasound machines are available for at-home use and they do improve the skin appearance.
Anti-inflammatories treat active redness and calm skin to prevent flushing and skin sensitivity. Foods that tame inflammation include kale, spinach, brussels sprouts, dark leafy vegetables, salmon, flaxseeds, legumes, turmeric and fruits such as blueberries and strawberries. When a cell is irritated it releases inflammatory substances such as cytokine and histamine. They alert the immune system of the irritation. The immune system responds by rushing leukocytes to the site of irritation. This site becomes red colored, because leukocytes get mixed with red blood cells.
Leukocytes also release cytokine which signals cells to produce protease. This enzyme breaks down collagen, elastin and hyaluronic acid responsible for skin firmness, elasticity and moisture content, respectively. The outer portion of the cell plasma membrane is attacked by sunlight-induced free radicals resulting in the release of fatty acid, called arachidonic acid, which is readily transformed into a powerful inflammation-causing chemical. These free radicals also stimulate the production of a compound in cells, called nuclear factor kappa B (NFKB), which turns on production of harmful compounds influencing micro-scarring, which leads to wrinkles. Sunlight also activates another messenger in the cell, AP-1, which signals the cell to produce enzymes to breakdown collagen, eventually resulting in aging skin. Many of these reactions occur simultaneously, producing a slow gradual deterioration of the skin. There are more than 50 different tropical products with powerful anti-inflammatory activity.
Perricone the Pioneer
Many of these topical anti-inflammatory ingredients were patented by Nicholas Perricone, MD in the early 1990s. Topical vitamin E is also an anti-inflammatory antioxidant. The leaves of chamomile plant have well-established anecdotal reputation for soothing, anti-inflammatory properties. Other botanicals including aloe, licorice, kukui nut, shea butter and avocado oil have been studied for their anti-inflammatory properties with proven benefits.
Antioxidants provide many benefits. They neutralize free radicals that occur naturally on the skin, and can reduce sun damage and skin aging. Some of the antioxidants include β-carotene, plant extract of gingko biloba, centella asiatica, ginseng, rosemary, juniper, horse chestnut, phytic acid and iron chelators. Other popular ones are vitamins C, D, and E; alpha lipoic acid; co-enzyme Q10; and green tea.
Vitamin E is considered an antioxidant superstar. It is lipid soluble and available in eight forms. Several studies support green tea’s potent antioxidant and anti-carcinogenic properties. Excellent botanical sources of antioxidants include berries, pomegranate, ginger, grapes, orange, plum, pineapple, lemon, dates, kiwi and grapefruit; as well as legumes like broad beans, pinto beans, soybeans, nuts and seeds, apricots and prunes. Antioxidant-rich vegetables include kale, chili pepper, red cabbage, bell peppers, parsley, artichoke, brussels sprouts and spinach; cereals such as barley millet and oats; and finally, roots and tubers such as carrots and red beets. Grapeseed extract, pycnogenol and green tea extract all contain polyphenols, which are not only powerful antioxidants, but are complimentary in enhancing the effects of other antioxidants.
A healthy barrier function prevents water loss and protects against irritants, insults and bacterial infection. Factors that promote healthy barrier include inter-cellular lipids, natural moisturizing factor (NMF) and number of stratum corneum layers. Promoting barrier repair improves dryness, roughness, redness, irritation, acne, rosacea, facial flushing, fine lines and uneven skin tone.
Ceramides are the major component of the skin surface. They protect against moisture loss to keep skin youthful and nourished from within. They play an important part in cellular signaling such as regulatory differentiation, proliferation and programmed cell death. The ceramides are expensive and are usually found in high-end cosmetics. Natural ceramides are extremely unstable and very costly to obtain, so synthetic grades are used. Synthetic ceramides do not penetrate the skin as well as natural ones; a problem that can be resolved if they are encapsulated in liposomes. There is extensive medical evidence supporting their potential for promoting the development of healthy skin cells. Other beneficial barrier protective ingredients include ginkgo biloba, green tea, black tea, grape seed extract, licorice, coenzyme Q10, vitamin C, pycnogenol, silymarin, quercetin, allantoin, chamomile, aloe vera and bisabolol. They reduce UV-induced inflammation, and are very beneficial to consumers with sensitive skin.
According to Shaheen Majeed of Sabinsa Corporation, skin often becomes sensitive when the natural barrier function is impaired, when nerve endings in the top layers of the skin become extra sensitive, or when it becomes intolerant to various triggers. The results can mean redness and inflammation and as a consequence, a need for an ingredient that can counteract it. Frequent use of detergents or soaps is a major cause of irritation. Recent studies have shown that cigarette smoke disrupts the barrier of the skin in a manner comparable to UV radiation. As a consequence of lipid depletion, the transepidermal water loss (TEWL) is increased. This results in lower water holding capacity. Typical ingredients that are helpful for barrier repair and protection are: ceramides, long chain fatty acids, sterols, glycerin, dimethicone and cyclomethicone. These agents help with dryness and restoration of the skin barrier and provide help to ameliorate dry skin and eczema.
The regenerative property of plant stem cells has captured the imagination of cosmetic researchers. Stem cells are becoming a common ingredient in skin products. It is important for researchers to know that stem cells, and cells in general, are notoriously difficult to keep alive in a laboratory, let alone in a skin care formulation. Nearly all cosmetic products that are promoted for their stem cell content actually contain stem cell extracts—not live stem cells.
Many dermatologists often use stem cell-conditioned media with growth factors, to regenerate the skin. Newer studies suggest that bone marrow stem cells are preferable as they are the ones that normally control healing. According to dermatologists, Leslie Bowmann, MD and Richard Hope, MD, plant-based stem cells are too large to penetrate the skin. They cannot live in the cream while it stays on the shelf for months or even years. These cells are dead basically and have no activity. Dr. Hope, however, believes human stem cells will likely have an impact on skin rejuvenation and hair restoration. The science is just beginning to understand human stem cell biology and finding ways to exploit this knowledge to reverse signs of aging. This research comes when consumers crave immediate product benefits, and seek authoritative advice and endorsements on their selected brands. It is hoped that these seven cosmeceutical categories and their mechanism of action will enable formulators match the right brand to the specific skin need.
Navin M. Geria
Chief Scientific Officer
AyurDerm Technologies, LLC
Navin Geria, former Pfizer Research Fellow is a cosmetic and pharmaceutical product development chemist and the chief scientific officer of AyurDerm Technologies LLC, which provides Ayurvedic, natural and cosmeceutical custom formulation development and consulting services to the spa-wellness-dermatology industries. He has launched dozens of cosmeceutical and ayurvedic anti-aging products. Geria has more than 30 years of experience in the personal care industry and was previously with Clairol, Warner-Lambert, Schick-Energizer, Bristol-Myers and Spa Dermaceuticals. He has nearly 20 US patents and has been published extensively. Geria edited the “Handbook of Skin-Aging Theories for Cosmetic Formulation Development” focus book published in April 2016 by Harry’s Cosmeticology. He is a speaker, moderator and chairman at cosmetic industry events.