The list of approved preservatives in Annex V of the EU Cosmetics Regulation is extensive – but the way we think about them has changed dramatically. Over the years, the industry has moved away from traditional systems like formaldehyde donors toward more skin-friendly alternatives. Today, preservation is no longer just about protecting the product, but also about protecting the skin – especially when it comes to sensitive skin types.
However, attitudes toward preservatives have changed significantly. I remember very well when Professor Dr. Tannert (Cosmetics and Detergents Technology) discussed preservatives in a lecture and talked about formaldehyde donors. A few years later, Willi Petersen (former CEO of Dr. Straemans) visited me at my former employer and told me about alternative preservation methods. I must admit that I didn’t understand much at the time. But today, alternative preservation methods are firmly established in cosmetics.
The Link Between Sensitive Skin and Light Scent
If you look at Annex V of the Cosmetics Regulation today, there are not many preservatives left that can be used. The main reason for this reduction is the potential for irritation or allergic reactions associated with some of the listed preservatives. Substances such as formaldehyde donors are no longer used, reflecting a fundamental shift in how preservation is approached.In the past, the priority was product protection – ensuring that formulations were completely free of microorganisms. Unfortunately, this often came at the expense of skin tolerance. Preservatives cannot distinguish between cream and skin, so while products were microbiologically safe, some consumers experienced allergic reactions.Today, the balance between product protection and skin protection is much more important. Looking at the 55 preservatives in Annex V from this perspective, benzoic acid, sorbic acid, dehydracetic acid, salicylic acid, phenoxyethanol, benzyl alcohol, and parabens remain. Even on this already very short list, there are some preservatives that should not be used when it comes to sensitive skin. This leaves only benzoic acid, dehydracetic acid, phenoxyethanol, and benzyl alcohol. If it also needs to be low-odor or fragrance-free, benzyl alcohol is also omitted.This is where alternative preservation methods come into play. In most cases, alternative preservation is not only milder, it also significantly expands the possibilities. However, due to its mildness, the dosages are also higher in most cases. This can be explained quite well with glycols. Glycerin (C-2) can only achieve its preservative properties through a very high concentration and a reduction in the aw-value, but it is very mild. With pentanediol (C-5), we have preserved many products with an application concentration of approximately 5%, however, a higher dosage is not recommended as the irritation potential would become too high. Octandiol (C-8) only requires approx. 0.7%, but the irritation potential is correspondingly higher, although this can be reduced by using a lower dosage.
Choosing Preservatives for Sensitive Skin
The big question is: what exactly defines a mild preservative, and when can a preservative system be considered mild? The answer varies between regions, as Asian skin tends to be more sensitive to surface-active preservatives than European skin. There are few, if any, studies on this topic, so my recommendations are based on experience and professional judgment. For instance, some consider sodium benzoate perfectly suitable for sensitive skin, while others would avoid it. Similarly, phenoxyethanol can be mild, but opinions differ. I consider alternative preservation to be a good approach, and the portfolio of options has expanded significantly in recent years; from p-anisic acid against mold to zinc sulfates for preservation support in W/O formulations. The selection of glycols is also very diverse, with pentandiol, hexandiol, heptandiol, octandiol, and ethylhexylglycerin.Active Concepts offers alternative preservation based on fermented raw materials. Fermentation takes place here, after which the cells are destroyed and the product is purified. This gives us a very mild alternative preservative that also supports the skin’s microbiome. It is possible to preserve cosmetics using these raw materials alone, but combining them with glycols, for example, makes the preservation process much more stable. Their very low odor also makes them an interesting option.Since alternative preservatives have both strengths and weaknesses, it makes sense to have a diverse portfolio so that these preservatives can be combined to achieve a balance. Preservation always has something to do with personal preferences, of course. I would combine our ferments with glycols. This would balance out the irritation potential at higher concentrations of glycols and the weak surface protection of our ferments, resulting in a safely preserved product. However, the widespread combination of p-anisic acid with levulinic acid is also a mild combination that works well. This combination is often combined with glyceryl caprylate. In my experience, however, care must be taken here, as glyceryl caprylate is no longer suitable for sensitive skin at concentrations of 0.5% or higher. 0.2-0.3% should not be exceeded here. Longer-chain glycols (C6-C8) should be dosed carefully and combined with other milder systems.
And what about the smell?
Smell is also something very personal, and everyone perceives it differently. Raw materials such as phenethyl alcohol are certainly out of the question, as they have a very strong inherent smell, but pentylene glycol also has a distinctive smell. p-Anisic acid, levulinic acid, our fermentation products, and others are fairly odorless. Ultimately, it’s a matter of trying things out and combining them to find your own optimal combination.
Concluding remarks
In recent years, the preservative landscape has changed significantly and many problematic raw materials have disappeared from the market. What remains is an essence of conventional and alternative preservation, most of which already takes into account the balance between product protection and skin protection. Alternative preservation can significantly expand the possibilities here and, in some cases, make the systems even milder or less odorous; it depends heavily on the product requirements and philosophy.
Richard Wazinski
Technical Sales Manager, Active Concepts, Bareggio, Italy, www.activeconceptsllc.com