EXPENSIVE MOISTURIZERS ARE MORE EFFECTIVE

For many consumers, price equates with quality. This may be true for some commercial purchases, but is not necessarily true for moisturizers. The most expensive part of any facial moisturizer is the fragrance, the bottle, and the packaging. None of these contributes to the efficacy of the moisturizer, only the aesthetic appeal. A quality moisturizer should cost less than $30 a bottle and products priced above this amount are selling more than skin efficacy. A quality moisturizer should contain an occlusive agent, a humectant, and some form of silicone. Ideally, it should also contain a sunscreen to provide the added benefit of sun protection. No moisturizer in any price range will improve the wrinkling on the lower face demonstrated in Figure 29.1.

Fig. 29.1 No moisturizer can improve perioral wrinkling that is due to muscles of facial expression, loss of facial subcutaneous fat, and facial osteoporosis

MOISTURIZERS REMOVE WRINKLES

Moisturizers do not remove wrinkles, they simply minimize their appearance. The role of moisturizers in reducing wrinkles is primarily through increased skin hydration. The moisturizer contains an occlusive agent, such as petrolatum, mineral oil, or dimethicone, which prevents transepidermal water loss from the skin surface and increases the water content of the skin. This increased water content decreases or even eliminates wrinkles that are due to stratum corneum barrier defects. Barrier repair will prevent the wrinkles from recurring and the moisturizer creates an environment to initiate barrier repair. Thus, moisturizers do not remove wrinkles (Fig. 29.2), they simply can provide an environment to reverse dehydration due to stratum corneum barrier defects.

Fig. 29.2 Coarse wrinkles on the lateral face do not improve with moisturization, since they are not due to cutaneous dehydration

COSMECEUTICALS CAN PRODUCE BENEFICIAL EFFECTS ON FACIAL MUSCLES TO IMPROVE SKIN TONE

The first cosmeceutical introduced to produce an effect on facial muscles was DMAE, which is dimethylaminoethanol. It is a releaser of acetylcholine, a neurotransmitter required for muscle movement. DMAE was originally introduced as a homeopathic nutritional supplement for individuals with Alzheimer’s disease and children with attention deficit disorder (ADD). The highest natural food source of DMAE is salmon, which explains the recent interest in diets incorporating several servings of the fish weekly.

The idea of using DMAE to improve the appearance of the facial skin is based on the concept that the facial skin must cover a bed of facial muscles. If the underlying muscle layer is contracted and firm, the skin has a better framework over which to lay. This may create an improved facial appearance, which is sometimes characterized by the cosmetic phrase ‘better skin tone’. The first several times that DMAE is applied a skin-tingling sensation is present; however, this disappears with continued use. It is unclear whether accommodation occurs to topical cosmeceuticals intended to alter muscle function with time.

Another group of cosmeceuticals, composed of engineered peptides, claims to interrupt the neuromuscular junction and relax facial muscles, functioning in a manner opposite to DMAE. The peptide is intended to mimic the effect of botulinum toxin.

In conclusion, much research and many clinical studies remain to be done on these cosmeceuticals designed to increase or relax facial muscle tone.

BLEACHING CREAMS CAN IMPROVE BROWN SPOTS QUICKLY

Unfortunately, no botanical, hydroquinone or mequinol-based bleaching cream can quickly improve the appearance of brown spots. Most products take at least 6 weeks and possibly even 3 months to work. This is because none of the bleaching cream actives is effective at removing melanin pigment from the skin. They all work by interrupting one step in the pathway of melanin synthesis or melanosome transfer. This means that the bleaching creams are shutting down new pigment production while the old pigment is being dispersed by traditional physiologic mechanisms.

Bleaching creams are most effective when used on the face due to enhanced penetration through thin skin. Neck, chest, and forearm hyperpigmentation responds even more slowly to treatment due to the decreased penetration of the active (Fig. 29.3).

Fig. 29.3 Neck hyperpigmentation is extremely difficult to treat with bleaching creams

GLYCOLIC ACID PEELS MUST HURT TO BE EFFECTIVE

There is a misnomer that the ‘no pain, no gain’ philosophy applies to both muscles and the skin. While muscles must be exercised to the point of exhaustion to promote increased muscle mass, this is not the case with the skin. Any procedure that induces pain is injuring the skin. Sometimes dermatologists injure the skin for what are considered to be medically beneficial reasons, but injury is still occurring. For example, glycolic acid peels are intended to exfoliate the outer layer of skin, removing unwanted melanin pigment and producing smoother skin with better color (Fig. 29.4). However, pain may indicate that the skin has been injured and the resulting inflammation may actually worsen skin color through postinflammatory hyperpigmentation. Peels that are intended simply to remove the stratum corneum should not hurt. Thus, glycolic acid peels do not have to hurt to be effective.

Fig. 29.4 The typical equipment used to administer a mild facial peel

COSMECEUTICALS NEED TO PENETRATE THE SKIN BARRIER TO WORK

Cosmeceuticals can function in many different skin compartments. Petrolatum, mineral oil, and dimethicone function on the skin surface and must not penetrate the skin. Retinoids do not function on the skin surface and must penetrate into the dermis to reach the retinoid receptors to have an effect. As this book demonstrates, cosmeceuticals are a diverse category of actives and each must be considered separately. Not all cosmeceuticals must penetrate the skin barrier to work.

TOPICAL FORMULATIONS OF VITAMINS AND SUPPLEMENTS ARE SIMILAR TO PILLS IN EFFECTIVENESS FOR SKIN IMPROVEMENT

The comparison between the efficacy of oral vitamins and supplements and topical vitamins and supplements is an ongoing area of controversy in the aesthetic and cosmetic world. However, I believe there is little room for dispute in medical circles that oral consumption of vitamins and supplements is far superior in efficacy to topical application. Yet, there are some effects of topical vitamins that cannot be achieved with oral ingestion. For example, topical vitamin E is an effective emollient allowing a rough skin surface with stratum corneum disruption to feel smooth and soft to the touch. Oral consumption of vitamin E cannot enhance skin texture, since vitamin E internally can only function as an antioxidant. Thus, there are unique topical and internal benefits to various vitamins.

VITAMIN-CONTAINING PRODUCTS CAN REVERSE PHOTOAGING

There are many cosmeceutical skin care preparations containing the antioxidant vitamins A, C, and E. It is interesting to note that no vitamin claims are made for most of these products. No cosmeceutical claims to reverse photoaging with these vitamins because that constitutes a drug claim and the Food and Drug Administration (FDA) would send a warning letter to the company asking them to either stop making the claim or remove their product from the market. Most cosmeceuticals simply claim that they contain the vitamin and the consumer is left to decide the topical vitamin benefits. Thus, vitamin-containing products can ‘help reduce the appearance of photoaging’, but cannot ‘reverse photoaging’.

RETINOL IN OVER-THE-COUNTER PREPARATIONS WORKS LIKE PRESCRIPTION TRETINOIN

Retinoids are a complex family of cosmeceuticals covered in Chapter 6. Retinol is the retinoid vitamin form that is necessary for vision. If the retinol is properly stabilized, it is possible that the skin can enzymatically convert small amounts of retinol to tretinoin. While this is theoretically possible, it has never been quanititated.

A SUNSCREEN WITH AN SPF ABOVE 15 DOES NOT PROVIDE ADDITIONAL PHOTOPROTECTION

Sunscreens above SPF 15 do actually provide additional photoprotection, but the increase in the amount of photoprotection provided is small. The percent UVB photoprotection provided by a given SPF rating is summarized in Table 29.1.

Table 29.1 UVB photoprotection provided by a given SPF rating

Notice that an SPF 4 sunscreen blocks 75% of the UVB radiation, but an SPF 15 sunscreen blocks 93%. Although this is a substantial improvement in photoprotection, the percent increase in UVB protection decreases as the SPF increases such that an SPF 30 product only has 4% more photoprotection than an SPF 15 product. Thus, dermatologists typically recommend SPF 15 sunscreens to combine product function with aesthetic characteristics, since higher SPF products tend to be sticky due to increased concentration of the sunscreen actives. Higher SPF products may provide value in patients with unique medical UVB photosensitive disorders.

It is important to remember that the single most common reason sunscreens fail is due to incomplete film formation over the skin surface. This may be due to uneven application or migration of the sunscreen over the skin surface. Figure 29.5 is a 400 × video microscope of the appearance of a sunscreen containing facial foundation on the skin surface. Notice how the film has begun to separate 2 hours after application. This means that the sunscreen will not deliver the SPF labeled amount of sun protection after 2 hours. Frequent reapplication of sunscreen products is essential to achieving adequate sun protection.

Fig. 29.5 A 400 × video microscope image of facial foundation on the skin surface

SELF-TANNING COSMECEUTICALS PROVIDE SUN PROTECTION

Self-tanning cosmeceuticals are based on dihydroxyacetone (DHA) as the active. DHA is a 3-carbon sugar that is manufactured as a white, crystalline hygroscopic powder. It interacts with amino acids, peptides, and proteins to form chromophobes known as melanoidins. Melanoidins structurally have some similarities to skin melanin. The browning reaction that occurs when DHA is exposed to keratin protein is known as the Maillard reaction. DHA is technically categorized as a colorant or colorless dye. It is added in concentrations of 3–5% to self-tanning preparations. Lower concentrations of DHA produce mild tanning while higher concentrations produce greater darkening. This allows self-tanning products to be formulated in light, medium, and dark shades.

The depth of color produced by self-tanning products is enhanced by increasing the protein content of the stratum corneum. As might be expected, skin areas with more protein stain a darker color. For example, keratotic growths such as seborrheic keratoses or actinic keratoses will hyperpigment. Protein-rich areas of the skin, such as the elbows, knees, palms, and soles, also stain more deeply. DHA does not stain the mucous membranes, but will stain the hair and nails. The chemical reaction is usually visible within 1 hour after DHA application, but maximal darkening may take 8–24 hours.

DHA is a nontoxic ingredient both for ingestion and topical application. It has a proven safety record with only a few reported cases of allergic contact dermatitis. Unfortunately, the browning reaction does not produce adequate photoprotection. At most, self-tanning preparations may impart an SPF of 3–4 to the skin for up to 1 hour after application. The photoprotection does not last as long as the artificial tan. The brown color imparts limited photoprotection at the low end of the visible spectrum with overlap into the UVA portion of the spectrum. DHA used to be approved as a sun protective agent in combination with lawsone; however, the new sunscreen monograph has removed this ingredient largely due to its lack of popularity. However, DHA remains popular as a safe alternative to a sun-induced tan, but for all practical purposes should be considered by the dermatologist as providing no sun protection.

NANOPARTICLES INCREASE ANTIAGING COSMECEUTICAL EFFICACY

Many efficacy claims are being made for cosmeceutical formulations containing nanoparticles. Nanoparticles are small spheres with a diameter between 1 and 100 nm. They are not truly new, but rather commonly found in the environment as a byproduct of fire or combustion. Nanoparticles are present in automobile exhaust, airplane exhaust, and air pollution in general. There is growing concern over the presence of nanoparticles in the environment. These particles are invisible to the human eye and can penetrate the skin and lung tissues, gaining access to the lymphatics and blood circulation. From there, these particles can be widely distributed throughout the body. Unfortunately, once these particles enter the body, they cannot be removed.

At present, nanoparticles are being investigated for use in sunscreens containing zinc oxide and titanium dioxide. However, nanodispersed organic sunscreen formulations containing benzophenone or octyl methoxycinnamate have also been created. All of the nanoparticle sunscreens have the same health concerns of unwanted penetration, since sunscreen actives are intended to stay on the skin surface. The possible dangers arise over concern as to what happens once the nanoparticle titanium dioxide or zinc oxide has penetrated the skin. Both titanium dioxide and zinc oxide are chemically inert. They are theorized to remain in the body indefinitely, either forming a reservoir within the dermis or spreading throughout the body via the circulation. It appears that the sunscreen particles are capable of absorbing and reflecting UV radiation within the skin, causing the generation of oxygen radicals within the dermis and initiating the inflammatory cascade. No one knows if this nanoparticle sunscreen reservoir might enhance the photoprotective abilities of the skin or prematurely age skin due to chronic low-grade inflammation characterized by unusually high levels of interleukins 8 and 12. Thus, the safety of nanoparticles and their use in cosmeceuticals remains controversial, as no enhancement of efficacy has been demonstrated to date.

SCARCE COSMECEUTICAL INGREDIENTS ADD CUTANEOUS BENEFIT

Expensive cosmeceuticals may contain rare ingredients touted for their cutaneous benefits. For example, sea kelp harvested in San Diego and flown to New York for a 4-month fermentation process in magnetized tubes is the rare ingredient in a $2100 jar of facial moisturizer. Another $500 jar of facial cream contains rare caviar obtained in the Caspian Sea from the beluga sturgeon during the natural birthing process. The expense of the caviar is due to its regulation under the Endangered Species Act and the fact that the caviar must be harvested fresh and immediately transported to the laboratory for processing. Unless tested in a double-blind, vehicle-controlled study, there is no evidence that these unique rare ingredients provide any skin benefit. It is certainly true that expense does not necessarily correlate with efficacy in topical antiaging cosmeceuticals.

LIP PLUMPING COSMECEUTICALS INCREASE LIP SIZE

The approval of new injectable fillers to enhance lip fullness has created tremendous interest in topical cosmeceuticals to replicate this effect. Many of the topical cosmeceutical lip plumpers contain small hyaluronic acid spheres. These spheres expand when placed on the skin surface in an oily lip moisturizer. They can absorb up to 25 times their weight in water and collect in the folds of the lip, expanding to create a more even surface for lipstick application. The effect is temporary until the spheres are removed. Most of the lip plumping cosmetics are rich in silicone technology to improve the shine and smoothness of the lips. Dimethicone is the main shine ingredient, but it must be combined with other silicones to stay in place. Stearyl dimethicone is an alkylmethylsiloxane that is a wax instead of an oil, which melts at body temperature to increase lip hydration. This can be combined with perfluoronyl dimethicone to increase the wear of the lip cosmetic and make the lips feel smooth. Cosmeceutical lip plumpers can make the lips appear smoother, but do not physically increase lip size.