Trends in Active Ingredients in Cosmetic Products Karl

Trends in Active Ingredients in Cosmetic Products
Karl LINTNER, PhD
Already 50 years…or should we say "Only 50 years"? Active ingredients have been
used for at least 3000 years in cosmetic products. Or have they? When did the notion
of "active" ingredients arise? With Cleopatra and ewe's milk? Or with ceruse (lead
oxide) to whiten the skin in the middle ages? Or with the first grand-mother's cold
cream containing some plant extract concoction 200 years ago? Or with the
deliberate inclusion of glycerine as a humectant, maybe 100 years ago and
antiperspirants and deodorants first appearing in the 1890s with aluminum chloride
as the active ingredient? With Eucerine (actually Lanolin) in Nivea (Beiersdorf) in
1911 or with Fruit acids (AHA) in Fruition (Estee Lauder) 20 years ago?
In fact, it cannot be repeated often enough, the notion of "active ingredients" in
cosmetic products has neither a clear definition nor a legal existence, contrary to
pharmaceutical and, in some countries, quasi-drug products (QD, OTC, Functional
Cosmetics).
EVERYTHING, including the water that is a major component of most cosmetic
products, has – or may have – some activity on the skin and/or hair: the oils, the
emulsifiers, the simple humectants and emollients, and of course the specific
ingredients added to a formula to obtain special effects that appear to give added
value to the product. So how can we review the trends of "active" ingredients over
the last 50 years when we cannot define what they are? We must rely on common
sense, on accepted jargon and notions of the industry. My own way of defining (if this
is the word) "active" cosmetic ingredients is the following:
• An ingredient (molecule, substance, +/- complex mixture of components)
that brings about a measurable, desirable change in one or more
cosmetic skin (or hair) parameters
• The observed changes must be significantly better than those observed
for a "base" formulation (also called vehicle, placebo, baseline). It is to
be borne in mind that formulating a true, inert cosmetic "placebo" is
quite impossible as – see above – every ingredient has or may have
some physiological activity on the skin.
• What is not meant here (and surely treated in a different chapter of this
anniversary issue) are UV filters, preservatives (both antimicrobial and
anti-oxydant), pigments, hair dyes and similar functional basic
ingredients
With this in mind, (knowing that the idea of "active" ingredients, often misleadingly
called "cosmeceutical" ingredients, is essentially a marketing idea: it is the "actives"
that are the subject of advertising claims, or product positioning and competitive
distinction), we may try to retrace the history of the last 50 years of this non-entity…
1960s: cosmetic products profit, like everybody else, from the freedom and economic
expansion after the war; babyboomers buy into cheerful, optimistic, scientifically
sounding claims; glycerine, petrolatum and lanolin, Camomile extracts, milk and egg
derivatives (in shampoos) have their field day.
1970s: animal extracts make their appearance. Collagen (hydrolized for the most
part) extracted from cow hide is used and claimed as a moisturiser, film former.
Placenta extract from cows, but also plant oils from more or less exotic sources
(borage oil, evening primrose oil), are promoted as beneficial, innovative, "youth
restoring" ingredients. Vitamins (especially vitamin C and E, easy to source and to
explain to the consumer) make their appearance and get promoted as skin beneficial
'active' ingredients, mostly for their antioxidant activity (they still do, with little
additional evidence of their real clinical benefit, in spite of numerous in vitro studies
and animal experiments).
1980s: the first more sophisticated stories appear: shea butter as an alternative to
lanolin or petrolatum is introduced, with demonstration of its benefits to damaged,
dry, stressed skin. The high content of unsaponifiables ingredients (phytosterols,
cinnamic alcohols) is quantified and advanced as an argument to substantiate the
claims.
About at this period in time, the notion of connecting the "active" ingredient with a
claim and some sort of proof for this claim takes root. In parallel with the development
of increasingly documented and specifically promoted "active" ingredients,
instrumental methods to measure cosmetic benefits are being devised and
introduced. Now classic devices such as the Corneometer®, Sebumeter®,
Cutometer® make their appearance, others follow with time.
Animal extracts (spleen extract, liver extract, brain extract, cartilage
mucopolysaccharides, blood serum extracted/concentrated fibronectin, hydrolized
keratin, rooster comb extracted hyaluronic acid and many others are promoted,
increasingly accompanied by studies (in vitro and in vivo) that demonstrate some
cosmetic benefit for the use of these ingredients in addition to the "base" formulas.
The world (of cosmetic/personal care products) was by now essentially split into three
regions, based on a regulatory issue: The USA, Europe and the Rest of the world.
The distinction of "what is a cosmetic" and what claims could be made for these
products was severely restricted in the USA by the Food, Drug and Cosmetics Act, its
interpretation by the FDA and the FTC and by title 21 of the Code of Federal
Regulations CFR; this definition essentially excluded (and still does) any cosmetic
"activity" that could be considered a "physiological change of the skin"; the definition
of a "cosmetic product" was somewhat more liberal and flexible in Europe, based on
the new Directive 76/768/CEE of the Council of 27 July 1976, and was hardly
regulated at all in the Rest of the world at that time.
On the other hand, the notion of "active" ingredients had taken hold by now,
especially as the just mentioned 1976 Directive had made its impact felt; not only did
this Directive lead to the requirement of a cosmetic "dossier" with documentation on
the safety of the product, but the added requirement for "proof" of claims generated
increasing interest in ingredients which would make it easier, and more credible, to
substantiate these claims directed at the consumer. After all, success in the market
required increasingly strong claims (anti-wrinkle, "anti-age", oil-control, slimming and
anti-cellulite, skin brightening, skin firming etc. etc.). And the claims, needing proof
(visual, instrumental, quantifiable…) were easier to obtain for formulas containing
"active" ingredients (see above my definition of what is meant by this term). A
number of companies, specialising in the development of both "active" ingredients
and of claim substantiation methods, instruments, protocols entered this new niche
market, many (but not all) of them based in France.
1990s: A severe blow to this specialised field – and to the companies just mentioned
– occurred in the beginning of this decade: the "mad cow disease" (bovine
spongiform encephalitis) made the headlines, and together with the increasing public
concern about safety testing on animals, led to the brutally quick abandonment of
animal derived extracts and products, including foremost the "actives", by the
cosmetic industry. A typical case in point was given by the ceramides and
sphingolipids, complex molecules that had been discovered recently in the stratum
corneum of human skin, but whose sole source for industrial application at the time
was: cow brain lipids! It took some time before synthetic ceramides could be
developed to replace the banned animal derivatives. This turning away from
otherwise time honoured animal ingredients led to increased interest in
biotechnology, plant extraction and – though less popular because of image
problems, but advantageous because of well controlled supply, analytical
characterisation and toxicology profiles – pure synthetic molecules as a novel source
for cosmetic "active" ingredients. It is impossible to list all of these ingredients, even
categories of ingredients in the scope of this review. Ceramides (synthetic,
hemisynthetic, biotechnology derived and plant extracted) were an important
contribution to improved skin barrier repair formulas, alpha (later beta-) hydroxy acids
achieved considerable market success in skin care products by promising more rapid
skin renewal, wrinkle
reduction and surface
smoothness. They even
spilled over into hair
care
formulas
(shampoos
and
conditioners), a rare
feat
for
"active"
ingredients from skin
care. The success of the AHA based formulas (and the associated – increasingly
daring – claims) succeeded in attracting the authorities (FDA) attention which led to a
restriction of the concentration of AHAs that could be used in a cosmetic before it
became a drug.
Similarly, the discovery that retinoic acid, applied topically, had skin healing and
repairing activity that could lead to wrinkle improvement, initiated the era of the
"retinoids" (derivatives of the prescription-only retinoic acid). The era of
"cosmeceuticals" had arrived1. It was accompanied by increasingly detailed studies
of biological and biochemical activities of the "active" ingredients in in vitro cell culture
experiments, molecular biology studies, genomics, proteomics and metabolomics.
1
This term, a hobby horse of marketing, market researchers and the media, is as debatable as the term "active";
the FDA does not recognise it, neither do other regulatory bodies. It would be preferable to speak of the era of
"science based cosmetics" (rather than "active" or "cosmeceutical") as indeed more and more scientific evidence
is generated in the support of cosmetic claims which still, in general, remain below the threshold of
pharmacological claims. No new category needs to be defined (between cosmetics and pharma); after all, water
and glycerin, both active on the skin, have their newly discovered "cellular receptors", the aquaporins…
2000 and beyond: the most recent decade
in the history of "active" cosmetic ingredients
saw the introduction of biologically active
peptides. Although protein hydrolysates
(protein fragments that could also be called
"peptides") had been used since the 60's, the
idea of using specifically chosen peptide
sequences which may act at extremely low
levels (in the ppm range) and still show cosmetic, measurable, activity in topical
formulas, was new and quickly gained approval after a few market successes of
formulas containing them. Numerous biologically active peptides do exist in the
human organism, many of them have (or may have) properties useful for the skin, the
scalp and the hair and now find their place in cosmetic formulations.
A propos hair: the notion of "Cosmetic Actives" as discussed here is more often
associated with skin care than with hair care, probably because the hair is dead
tissue and not (so much) receptive to biological activity. But of course, hair care
products (shampoos, conditioners, masks, scalp treatment lotions) also may contain
ingredients that can be labelled "actives" (ceramides, other special lipids, proteins,
vitamins like Biotin, plant and marine extracts have been used). Especially successful
were whole lines based on "fruit acids" (AHA), panthenol, coal tar… Molecules such
as Minoxidyl, Zinc pyrithion, ketokonazole are indeed truly active ingredients, but fall
often into the OTC/QD category and outside the spirit of this short chapter.
What will the future bring for "active" ingredients in cosmetic formulas? Two trends
can be discerned: on one hand, the demand for "natural" ingredients (in most minds,
this means: plant derived) is on the increase; on the other hand, higher sophistication
of defined molecules, of well understood mechanisms, thus of truly "science based"
ingredients and associated claims seems to be path of the coming decades.
Whatever the choice and origin of ingredients, safety, quality and proven efficacy will
determine their acceptability by formulators, consumers and regulatory authorities.