The anti-aging category certainly isn’t showing its age. Global sales of anti-aging products are expected to grow 26% from 2011-2016 to reach $28 billion, according to a study by Euromonitor International. During that time, US sales of anti-aging products are expected to grow 46% to reach $12 billion.

No wonder why supermarkets and department store shelves are crowded with anti-aging products formulated with new cosmeceuticals, some of which make unsupported claims. Most consumers mistakenly believe that these products are regulated and tested as rigidly as drugs and that the claims made in advertisements are valid.

This column will briefly review promising cosmeceutical ingredients for which there is available clinical data that support skin appearance improvement effects. This information, hopefully, will help marketers to substantiate anti-aging claims for their new product launch in this growing category.

Efficacy
Effective cosmeceutical ingredients, when added to a formula correctly, provide optimum anti-aging efficacy. Ingredients such as retinoids, antioxidants, ascorbic acid, peptides, broad-spectrum sunscreens and MMP inhibitors provide collagen-boosting and matrix protection benefits. A combination of retinoids and alpha hydroxy acids provide skin texture improvement benefits too.

Skin pigmentation correction benefit is derived when retinoids are combined with l-ascorbic acid, anti-inflammatory agents, and melanogenesis inhibitors. These cosmeceuticals, alone or in combination, treat signs of aging which provide skin anti-aging  benefits such as improving firmness, elasticity, tone, clarity, radiance, sensitivity and texture, while reducing redness, blotchiness, fine lines and wrinkles, dryness, dullness, spider veins, drooping neck, sagging cheeks, lip wrinkles, frown lines, crow’s feet, photo-aging, enlarged pores and age spots.

Antioxidants
The most-widely studied antioxidants include resveratrol, ferulic acid, ergothioneine and idebenone. Resveratrol has chemo-preventative and cytostatic properties. When used topically, it provides UVB skin protection. It is effective antioxidant with strong anti-inflammatory properties.¹

Ferulic acid prevents nitric oxide production and lipid peroxidation. It absorbs UV radiation. Its free-radical scavaging effects are not as potent as green tea polyphenols.^2,3

Ergothioneine increases the protective activity of l-ascorbic acid and vitamin E. It accumulates within epidermal keratinocytes for long term protective benefits.^4,5

Idebenone is an analog of coenzyme Q-10. It decreases lipid peroxidation. It inhibits UVB-induced DNA damage and erythema.⁶

Green tea’s antioxidant activity is due to epigalocatechin gallate (EGCG). It prevents the formation of nitric oxide, hydroxyl radicals and singlet oxygen. It induces degradation of carcinogenic cutaneous cells.^7,8

Plant stem cells have antioxidant benefits. They provide protection and stimulation to epidermal stem cells.

Vitamin C reduces collagenase synthesis, as well as post-inflammatory and UV-induced erythema.

Retinoids
This family of cosmeceuticals includes retinoic acid, retinol, retinaldehyde and vitamin A esters.
Retinol and retinaldehyde provide topical benefits with reduced risk of irritation, while pure retinoic acid and retinol formulae may cause irritation.

Retinoids encourage proliferation of elastin and glycosaminoglycans. They decrease collagenase and elastase levels and reduce fine lines, roughness and dyspigmentation.⁹

Peptides
These synthetic compounds contain two or more amino acids connected by peptide bonds. They perform targeted functions in the skin when applied topically. There are four main categories. Signal peptides are palmitoyl pentapeptide-4, palmitoyl oligopeptide, palmitoyl tetra peptide-7 and palmitoyl tripeptide-38. They help produce collagen.

Neurotransmitter affecting peptides help relax wrinkles; e.g., acetyl hexapeptide-8 inhibits soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) complex.¹⁰

Enzyme-inhibitor peptides help improve under-eye circles and hyper-pigmentation and carrier peptides. They enhance delivery of active ingredients within skin layers; e.g., copper peptide increases collagen and elastin production. The evidence to support their use is growing. Popular peptides are Matrixyl (pentapeptide-4) and Argiriline (acetylhexapeptide-8).

Skin Lighteners
These botanical ingredients interfere with melanogenesis cascade, prevent the occurrence of future pigments and reduce the appearance of current skin pigmentations.

Hydroquinone is synthetically derived, but is also found in wheat, berries, coffee and tea. It increases the degradation of melanosomes, inhibits DNA and RNA synthesis and induces melanocyte-specific cytotoxicity.

Arbutin is found in blueberry leaves, wheat and pears. This potent antioxidant inhibits tyrosinase activity. It is less cytotoxic to cultured melanocytes than hydroquinone.

Kojic acid is derived from soy, rice and mushrooms. It inhibits nuclear factor-kappa B(NF-kB) activation in keratinocytes.¹¹ Other effective skin lighteners include retinoids, l-ascorbic acid, lactic acid, licorice root extract, azelaic acid and phenylethyl resorcinol.

Hydroxy Acids
This class of cosmeceuticals can turn dry, dull skin into smooth radiant skin more quickly than any other ingredient type. Hydroxy acids improve skin texture, skin barrier function and the appearance of photo-aged skin. However, they can cause redness, stinging, and burning in those with sensitive skin. Polyhydroxy acids or PHA are less irritating and are equally effective.

Although acids work rapidly, remember that there is no quick fix when it comes to skin benefit. If you see an instant effect, most probably it is due to visual correctors in the formula that temporarily tighten, swell or irritate skin.

For real benefits to occur, skin needs a minimum of eight weeks to undergo any significant change. It is therefore important to track clinical results for at least four months. To be effective, they must first cross the epidermis, and penetrate through the dermis and the fatty layer. 

References:

1. J. Cos. Derm. 2008:2-7
2. J. of the Science of Food & Agriculture 1999:476-480
3. Free Radical Research Communication 1993.241-253
4. Biochemical Communications 2003:860-864
5. Free Radical Medicine 2009: 46:1168-1176
6. J. Cos. Derm. 2005-10-17
7. Experimental Dermatol. 2006-678-684.
8. Proceedings of NAS 2002:12455-12460
9. Cosm. Derm. 2005-3-5
10. Int.J.Cos. Sci 2002:24 :303-310
11. Cosmetic Formulations of Skin Care Products.-2006:40

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Navin M. Geria
Senior Technical Advisor and Principal Doctors Skin Prescription
E-mail: [email protected]

Navin Geria, ex-Pfizer Research Fellow, is senior technical advisor and principal of the dermatological research company, Doctors Skin Prescription (DSP), Boston, founded by dermatologist David J. Goldberg, MD JD and plastic surgeons William P. Adams, MD FACS and Jason Pozner, MD. Geria has more than 30 years of experience in the personal care industry and was previously with Clairol, Warner-Lambert, Schick, Bristol-Myers and most recently, Spa Dermaceuticals. He has earned nearly 20 US patents, has been published extensively and has been both a speaker and a moderator at cosmetic industry events.