*Pr  C.Baudouin–Ophtalmologiste (Paris)

** Dr E. Collet–Dermatologue/Allergologue (Dijon)



Dermatological or ophthalmological products, from their manufacture to their use, are constantly subject to environmental constraints likely to alter their composition (microbiological contamination, oxidation, etc.). Due to high water and organic matter content, they are a breeding ground for bacterial contamination. They are often also used over long periods of time, which often leads to contamination by the user.

So, preservatives are an essential component of ophthalmic and dermatological preparations, in order to control antimicrobial activity in packaging and prevent degradation of the active substance. The most common are parabens, benzoic or sorbic acid salts, benzalkonium chloride, or chlorobutanol.

For several years, the controversy surrounding these components has led to the development of preservative-free formulations (1).

Indeed, many studies highlight their cytotoxic effects, especially when they are used over sustained periods.

Some ingredients for cosmetic manufacturers are sold in combination with preservatives.
Antimicrobial preservatives act on bacteria or microscopic fungi, stopping them from developing (bacteriostatic or fungistatic effect) or killing them (bactericidal or fungicidal effect).

They can work in three ways: by altering enzyme systems in the bacterial cell, by denaturing proteins, or by modifying the production system by denaturing nucleic acids. In this way, they protect products from contamination during manufacture and when being used by the consumer.

Antioxidant preservatives prevent oxidation by capturing free oxygen. The hydroxyls in their molecule contribute to reduction.
Alcohols that are sometimes present have a drying effect, or plant compounds and perfumes that may cause allergies, irritation and eczema are sometimes included in the ingredients.



We have long been convinced of the long-term harmful effect of preservatives in ophthalmology. And what goes for the cornea of the eye also goes for the horny layer of the epidermis. There are even more studies in dermatology than in ophthalmology that prove this. 

“Preservatives are the second most common cause of allergy after perfumes” (Dr E. Collet - Dermatologist/Allergist (Dijon)). They are responsible for irritation and contact eczema. 

Any component of a cosmetic or pharmaceutical product, and mainly preservatives, can lead to an immediate allergy (type 1). This type of reaction, typical of its manifestations, is stopped by withdrawing the allergen, which means taking away the product. 

Allergies to formalin-releasing agents are on the rise. They have also been classified as a “definite carcinogenic” by the IARC (International Agency for Research on Cancer). 

2-phenoxyethanol is a glycol ether widely used in dermatological products for its preservative properties. It does not have an irritating effect, but several cases of skin sensitisation (eczema or urticaria) have been reported after using it. (2) 

These are most often related to regular use of cosmetics. Carcinogenic risks or effects on reproduction through the use of phenoxyethanol have not been established. However, exposure to phenoxyethanol may cause neurotoxic effects (paraesthesia, headache, irritability, memory loss, etc.). (3)

 established. However, exposure to phenoxyethanol may cause neurotoxic effects (paraesthesia, headache, irritability, memory loss, etc.). (3)

CLARTé laboratoire PRODUCTS

CLARTé laboratoire PRODUCTS

It is to be noted that currently authorised preservatives are not harmful to health. However, they can cause significant effects and hypersensitivity when applied to reactive skin.

We formulated our products without preservatives with this type of skin in mind, as Horus Pharma had already done for its eyelid products.  

Moreover, many studies show a cumulative effect of these preservatives in the long term.

Finally, it should be noted that it is preferable to have products derived from chemical synthesis, but well-tolerated and stable, than potentially allergenic “natural” products. This is our conviction.

(1) (Papageorgiou S, Varvaresou A, Tsirivas E, Demetzos C. New alternatives to cosmetics preservation. J Cosmet Sci. 2010 Mar-Apr;61(2):107-23 : Learn more

(2) (Geier J, Lessmann H, Dickel H, Frosch PJ, Koch P, Becker D, Jappe U, Aberer W, Schnuch A, Uter W. Patch test results with the metalworking fluid series of the German Contact Dermatitis Research Group (DKG). Contact Dermatitis. 2004 Sep;51(3):118-30 : Learn more

(3) (Morton WE. Occupational phenoxyethanol neurotoxicity: a report of three cases. J Occup Med. 1990 Jan;32(1):42-5 : Learn more