Wednesday, January 2, 2013Ingredient of the month

Caffeine, the all-rounder active ingredient

©CosmeticOBS-L'Observatoire des Cosmétiques

Anti-cellulite, anti-bags, anti-ageing, anti-hair loss … what are the properties that caffeine is not given in cosmetics? This "magic" active ingredient is found in a larger and larger range of products. Even if its mechanisms of action are not yet clearly understood, even if its efficiency is not always scientifically proven. However, the trend should not go back, as new applications could soon appear. Underneath, some pieces of information to understand why decaf’ cosmetic is not the flavor of the month.

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~ 6 minutes

Caffeine is an organic molecule, an alkaloid, from the methylxanthines family, such as theophylline or theobromine, also used in cosmetics.
It is naturally present in more than 60 plants species the world over. It protects them from insects that are harmful, by killing or paralyzing them. It is found especially in coffee, from which its name comes, but also in tea, guarana, mate, cola nuts …
However, for obvious reasons of cost, the caffeine used in cosmetics is most often synthetic.

It is used in many categories of face and body care products: slimming products, eye-contour, anti-ageing or anti-redness creams, but also in anti-hair loss products; maybe soon in more and more sunscreens, in which it could help prevent skin cancers.
Indeed, it is renowned as being “anti-many things” against which cosmetics are called for help …

Anti-fat

Caffeine is the main active ingredient of the slimming cosmetic products, especially when they target cellulite.
As a general matter, it is used for its lipolytic action: in fact, it enhances lipolysis, the natural reaction of our body that destroys fats while providing it with a part of its needs for energy. Therefore, it is a means to limit fat storage.
Studies have also shown that caffeine improves the cutaneous micro-circulation; this influences the micro-vessels growth in tissues, and modifies the aspect of cellulite.

Can these results, observed in laboratories, be duplicated in human beings? Clearly, is caffeine efficient as a slimming agent?
Few studies are available to support this. One of the most recent, performed in 2007 by a Brazilian team of researchers on 99 women, reported, after a caffeine-based cream had been used for a month, a lower hip and thigh circumference, for 66.7% and 80% of them, respectively.
However, note that the product contained seven per cent of caffeine, when slimming cosmetics generally contain only two to three per cent. In fact, the lipolytic efficiency  of caffeine is dose-dependent; a noticeable efficiency could be seen with at least five per cent…

Further, it is known that caffeine can be efficient only if it arrives to its target, the adipocytes (the cells in which fat is stored) of the sub-cutaneous tissues. Thus, it must go through the cutaneous barrier. This is a point anticipated by most of the cosmetic formulations, which add skin penetration enhancers, such as PEG-7 Glyceryl Cocoate or alcohol (INCI: Alcohol, Alcohol denat.), which, in addition, increases its solubilization and prevents  its crystallization.

Anti-bags

We have already written about the ability of caffeine to increase micro-circulation.
It is also a vasoconstrictor (which contracts blood vessels and lowers their diameters), and a diuretic agent (it speeds up the drainage and the riddance of the excess water from tissues).
Along with a mild massage, or mild pats under the eyes, it is a decongestant active ingredient of choice to lower puffiness and bags or dark circles aspect.
This, even if no clinical study can support the in vitro transposition of the intrinsic properties of caffeine in eyes contours.

Anti-redness

The vasoconstrictor effect of caffeine is also useful in face cares. Lowering the blood vessels diameters may help lower redness, for instance, in case of rosacea.
However, keep in mind that its effect is low, and is not long-lasting. Results are gotten only by repeated and regular applications.

Anti-hair loss

Quite recently, caffeine-based anti-hair loss products have been placed on the market.

In fact, in vitro studies have shown it stimulates hair growth. In laboratories, it prevents the negative effects of testosterone (a masculine hormone, which is a factor of hair-loss) and delay baldness.

The prospect of an efficient anti-hair loss active ingredient (there is a dramatic shortage of such ingredients in the cosmetic industry) seems promising. However, there is, once again, a lack of clinical data and of a good understanding of the mechanism to draw final conclusions as per the caffeine efficiency in this area.

Anti-photoageing

The most-recent  properties attributed to caffeine: its anti-oxidant and anti-inflammatory properties.

The anti-oxidant effect of caffeine was already known, and its protective action, especially through food, is well documented. Thus, it was quite logical to use it in cosmetics, to fight free radicals, a cause or premature skin ageing, particularly in anti-ageing and anti-wrinkles products.

Moreover, several studies have shown that, when applied on skin, caffeine may lower damages to skin coming from exposure to UV radiation, thus, avoiding some cancers due to sun exposure. It could have a specific property: without any damage to healthy cells, it could speed up the death of cells whose DNA has been damaged by UV radiation. In fact, these damaged cells are the root for skin cancers. Targeting and destroying them, as caffeine does, mathematically diminishes the possibilities they continue to divide and grow … thus, the risks of cancers.

Anti-oxidant, a protection against the most harmful effects of UV radiation, and anti-inflammatory (thus, a means to delay sunburns), caffeine may soon be present in all our sunscreens, as well as anti-ageing, SPF-claimed foundations …

Anti-caffeine

A chapter is still lacking, when talking about all the “anti” linked to caffeine: the one that refers to people who shall avoid it.

Caffeine is a Generally Recognised As Safe (GRAS) ingredient, and as such, considered as safe for use by the sanitary authorities.
It has a mutagenic and teratogenic potential, but at doses far higher than that which one could be exposed to for a daily use. Some cases of hives or allergies have been reported after contact with it; nevertheless, this is a rare occurrence, and caffeine is well tolerated by skin, without any irritant effect.
The European regulation on cosmetics has not established any limit to its use; this means that manufacturers can use it in any kind of product, without any limit of percentage other than the technical limits due to formulations.

That being said, it may be responsible for undesirable effects, especially if overdosed: excitability, insomnia, shiver, heart rhythm troubles …
Obviously, the quantities of caffeine used in cosmetics cannot trigger these disorders alone, except in people who are hypersensitive to it. However, they shall be added to the caffeine from diet (coffee, chocolate, tea, sodas …), and the acceptable threshold, different from one person to another, could be exceeded, for instance, due to a slimming cream, applied every morning and evening. Yes, in fact, "cosmetic" caffeine goes through the cutaneous barrier (slimming products are specifically designed for that) and enters the blood stream, as "food" caffeine does.

However, this should not prevent it from being a major active ingredient in more and more cosmetic formulations … especially if new properties are discovered!

© CosmeticOBS-L'Observatoire des Cosmétiques
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