Cosmetics vs. Cosmeceuticals
The term Cosmeceuticals refers to cosmetics with pharmaceutical benefits.
When considering cosmeceuticals, it is helpful to look at how cosmetics and medicines are legally defined.
The Cosmetics Regulation states that a “cosmetic product” means any substance or mixture intended to be placed in contact with the external parts of the human body or with the teeth and the mucous membranes of the oral cavity with a view exclusively or mainly to cleaning them, perfuming them, changing their appearance, protecting them, keeping them in good condition or correcting body odors.
The Human Medicines Regulations provides that a “medicinal product” means any substance or combination of substances presented as having properties of preventing or treating disease in human beings, or that may be used by or administered to human beings with a view to restoring, correcting or modifying a physiological function by exerting a pharmacological, immunological or metabolic action, or making a medical diagnosis.
So we can see that while cosmetics focus on “cleansing, perfuming, protecting or altering the appearance”, medicines “prevent or treat disease, restore, correct and modify physiological function”.
Cosmeceutical skincare can, therefore, be thought of as topical skincare products that contain biologically active ingredients to improve the function of the skin.
In 1984, Albert Kligman, a dermatologist in the United States, first used the term “cosmeceuticals” to describe an emerging category of topical skincare products “…that provided therapeutic benefits to the skin above and beyond what would be seen with simple cosmetics.” Importantly, Dr. Kligman recognized how vitamin A encourages new collagen production by promoting rapid skin cell turnover.
The term “cosmeceutical” is derived from a combination of the words cosmetic and pharmaceutical.
We know that from as early as our twenties the body’s ability to produce new collagen starts to gradually slow down. With the use of targeted active ingredients, we can mitigate the effects of what would otherwise be occurring to our skin on account of the aging process.
Manufacturers of cosmeceuticals cannot make the same claims that can be made if the product were regulated as a medicine, though ingredients with proven efficacy and used at an appropriate strength can still offer benefits beyond non-active skincare.
WHAT ARE COSMECEUTICALS?
Cosmeceuticals are products that have both cosmetic and therapeutic (medical or drug-like) effects and are intended to have a beneficial effect on skin health and beauty. Like cosmetics, they are applied topically as creams or lotions but contain active ingredients that have an effect on skin cell function. In some cases, their action is limited to the skin surface (such as exfoliants), while others can penetrate to deeper levels, either enhancing or limiting normal skin functions.
Many brands claim to be cosmeceuticals, but true cosmeceuticals are available only through medical doctors.
These products are offered “over-the-counter” (without a prescription) and are generally used as part of a regular skincare regime to help improve skin tone and texture, pigmentation and fine lines.
Most moisturizers restore barrier function and water content to the skin, improving the appearance of aged or dry skin. Cosmeceuticals deliver the active ingredient in a biologically effective form to the skin and reach the target site in sufficient quantity to have a biological response.
THE DIFFERENCE BETWEEN COSMETICS AND COSMECEUTICALS
A cosmetic product doesn't penetrate beyond the outer surface of the skin and so it cannot directly treat a specific disease. It cannot pass through the dermal-epidermal joining, which is the area between the epidermis and dermis. However, it can maintain, protect, clean, add fragrance, and change the appearance of any area of the epidermis’ surface that it is applied to.
In contrast, cosmeceuticals are able to penetrate the epidermis. The active principles are able to pass through the epidermis and act deep within the dermis. Although, due to its composition, a cosmeceutical product is not classifiable as a drug, despite being formulated with highly active principles.
A product classified as a drug is any substance or combination of substances that have the ability to cure or prevent a specific disease. Its main purpose is to restore, correct, or modify the physiological functions through pharmacological action.
ACTIVE INGREDIENTS IN COSMECEUTICALS
According to their functions or effects, aesthetic dermatological active ingredients can be roughly classified into four main categories: moisturizing, antioxidant, cellular repairing, and extra-cellular matrix boosters.
Active ingredients can differ in their manufacturing origin as well as in their biological mechanisms of action.
The scientific evaluation of active ingredients is beyond the scope of this article but will be demonstrated and discussed in follow up articles.
An overview of popular active ingredient examples:
These are probably the most important ingredient in cosmeceuticals because they protect against sun damage, photo-aging, and skin cancers. Sunscreens are a good example of how cosmeceuticals have changed the product sector. Historically, sunscreens were in effect a physical barrier to block out the sun’s UVB rays. By incorporating antioxidants and other cell-repair ingredients into sunscreens, we are now able to also protect against UVA rays. We know UVA rays contain oxidants that slow the synthesis of collagen, an important cause of photoaging and skin laxity. By boosting the sunscreen with antioxidants we are offering additional cell protection.
External factors such as ultraviolet (UV) radiation, pollution and smoking, as well as internal factors including normal cellular metabolism, can generate molecules called free radicals which are damaging to the skin. Antioxidants “mop up” these free radicals thereby reducing inflammation and protecting the skin against sun damage and skin cancers. Some studies suggest that combinations of antioxidants can be more effective than single-ingredient formulations.
Antioxidant examples include:
- Vitamin C (Ascorbic acid or Tetrahexyldecyl ascorbate): Stimulates collagen repair and can improve fine lines, reduce inflammation and pigmentation. Although it is found in a number of cosmeceutical products, many are not effective because the vitamin C is unstable when exposed to air, heat or light, is in too low a concentration or in a form that cannot be absorbed or metabolized by the skin.
- Niacinamide (vitamin B3): An antioxidant that improves skin barrier function. It can reduce fine lines, wrinkles, and hyperpigmentation and improve skin texture. It may also play a role in skin cancer prevention.
- Vitamin E (alpha-tocopherol): Another antioxidant that reduces UV damage and skin cancer. It also works synergistically with vitamin C in reducing collagen break down.
- Ubiquinone (CoQ10): A naturally occurring antioxidant that reduces collagen breakdown due to sun exposure.
These can be classified according to their molecular structure into alpha-hydroxy acids (AHAs), polyhydroxy acids (PHAs), and beta hydroxy acids (BHAs). Hydroxy acids improve skin texture and reduce the skin signs of aging by hydrating the skin and promoting the shedding of dead skin cells from the outer layer of the skin (epidermis).
- AHAs include glycolic acid, lactic acid, citric acid, mandelic acid, malic acid, tartaric acid, and lactobionic acid.
- PHAs include gluconolactone and lactobionic acid.
- The main BHA used is salicylic acid which is particularly useful in people with oily or acne-prone skin because of its fat solubility and ability to penetrate pores.
Retinoids (vitamin A)
These are natural or synthetic forms of vitamin A that can partially reverse skin changes induced by sun exposure. Common retinoids include tretinoin or retinoic acid, retinol and retinaldehyde. They act as antioxidants, protecting cells from free radicals, as well as activating specific genes and proteins. Topical tretinoin has been shown to improve the appearance of photodamaged skin by reducing fine lines and wrinkles, skin looseness (laxity), and excess pigmentation, as well as improving skin texture. Tretinoin can cause side effects such as burning, stinging, redness, and flaking.
Skin lightening agents
This helps inhibit the production of melanin (the main skin pigment) to reduce skin discoloration and pigmentation.
Skin lightening examples include:
- Glycolic acid
- Vitamin C (Ascorbic acid or Tetrahexyldecyl ascorbate)
- Kojic acid
These include plant extracts from leaves, roots, fruits, berries, stems, bark, and flowers. Botanicals may have antioxidant, anti-inflammatory, and/or skin-soothing properties, however, their effects remain largely untested or unproven. Examples include soy, curcumin, silymarin, pycnogenol, ginkgo Biloba, green tea extract, grape seed extract, aloe vera, witch hazel, allantoin, and ferulic acid.
Peptides and proteins
Peptides are short chains of amino acid sequences that are the building blocks of larger proteins. Cellular “messengers” formed from amino acids can imitate normal biological signals that either stimulate repair or inhibit processes that accelerate skin aging. Examples include the pentapeptides (Argireline and Matrixyl).
Every day in clinical practice, medical practitioners see patients who ask them if cosmeceutical products are beneficial. Accurate advice is a challenge that requires knowledge of the structure and function of human skin and the available scientific data, which may or may not support the efficacy of a given cosmeceutical product. As medical doctors, it is very hard to keep up with the latest evidence on the popular cosmeceutical ingredients due to the vastness of ingredients, the multitude of commercially available products and their efficacy claims, and the validity or accuracy of data gleaned from in-vitro and clinical studies, if available.
Questions to be asked when scientifically evaluating the potential therapeutic merits of a cosmeceutical:
According to Dr. Albert Kligman, when asked to evaluate a new cosmeceutical product that claims a beneficial physiological effect, it is important to ask three questions:
Can the active ingredient penetrate the stratum corneum (SC) and be delivered in sufficient concentrations to its intended target in the skin over a time course consistent with its mechanism of action?
Does the active ingredient have a known specific biochemical mechanism of action in the target cell or tissue in human skin?
Are there published, peer-reviewed, double-blind, placebo-controlled, statistically significant, clinical trials to substantiate the efficacy claims?
When evaluating a cosmeceutical ingredient, it is important for physicians to access the scientific literature, not only in medicine but also in basic pharmacology and biochemistry, to verify that the claims made for active cosmeceutical ingredients are backed by a well-defined body of evidence.
Medical science and biotechnology have played increasingly greater roles in the beauty industry due to growing consumer demand for advanced cosmetic formulations and efficacious ingredients. Cosmeceuticals are the manifestation of convergence of science, medicine, and beauty, and have revolutionized the world of skincare. By understanding the basic scientific mechanism of how cosmeceuticals work on the skin, one can design more specific products, addressing a wide range of functions that the end-user can rely on.