Fragrancing Cosmetic Formulas

WHY ARE COSMETIC FORMULATIONS PERFUMED?

The way we perceive fragrance is highly individual and often evokes strong emotions — what one person finds appealing may be completely unacceptable to another. At some point in our lives, most of us have experienced a moment when a scent encountered unexpectedly brought back vivid memories from many years ago.

This happens because our sense of smell is closely connected to the olfactory brain — a structure involved not only in processing smells, but also in memory consolidation and the regulation of emotions. This is precisely why fragrances and perfumes have such a powerful ability to trigger intense emotional responses. As Patrick Süskind, author of Perfume: The Story of a Murderer, puts it:

“Smell enters human beings along with the breath and people cannot defend themselves against it [...] And smell goes straight to the heart and there decides quite categorically between affection and contempt, disgust and lust, love and hate. He who ruled scents ruled the hearts of men.”

In the cosmetics industry, there is a common belief that a well-chosen fragrance composition accounts for half of a product’s success. When testing a new cosmetic, consumers often assess its scent before paying attention to other properties of the formulation. If the fragrance does not meet their expectations, they may simply decide not to use the product again.

Selecting the right fragrance composition is therefore a challenge not only for marketing and product development teams, but also for formulators and perfumers. And choosing a fragrance is only the first step in a much longer process. After all, a perfume is a mixture of chemical substances that can interact both with one another and with their environment.

So, what can be used to fragrance cosmetic formulations? What are the advantages and disadvantages of each option? And is adding a fragrance composition necessary at all?

The use of cosmetics stems from the need to maintain personal hygiene and care for the body, which naturally produces unpleasant odours as a result of various physiological processes. In order to eliminate them, we need to take a twofold approach — get rid of what is unpleasant and leave behind what is attractive.

This brings us straight to the heart of the matter: cosmetics should smell pleasant in order to enhance the overall user experience and quality of life. In addition, unfragranced cosmetic formulations often have a distinctive “chemical” or oily odour, so adding fragrance can also significantly improve their sensory properties.

As in every other area of life, perfumery is subject to trends. Anyone who has been loyal to a particular fragrance for years and then struggled to purchase it again will know exactly what this means. The old makes way for the new — and the removal of even a single allergen from the 26 fragrance allergens traditionally required to be declared in the INCI list can turn the cosmetics industry upside down.

The introduction of restrictions and bans on ingredients such as Lyral and Lilial has caused manufacturers considerable difficulties and additional costs. This is because they have had to abandon fragrance compositions that consumers had grown accustomed to, find suitable alternatives, carry out numerous stability tests, and purchase new raw materials.

Certain trends can also be observed in fragrance compositions used in cosmetics, such as replacing synthetic ingredients with natural ones or switching entirely to essential oils. The choice of fragrancing strategy depends on several factors, including the marketing concept, the intended use of the product and, of course, the available budget.

So, what exactly are cosmetic formulations fragranced with?

CLASSIC FRAGRANCE COMPOSITIONS

The simplest and most popular method of fragrancing a cosmetic formulation is to use a ready-made fragrance composition (INCI: Parfum). Fragrance suppliers offer hundreds of thousands of different scent variations. These are highly complex mixtures of chemical substances, primarily made up of synthetic ingredients, sometimes combined with natural ones. Depending on the intended application, they may contain different carriers or solubilizers — for example, PEG-40 Hydrogenated Castor Oil or Polysorbate-20 for shampoos and creams, or Isopropyl Myristate for oil-based products such as body butters, oils and lip balms.

Fragrances themselves can be classified in many different ways. The average consumer tends to distinguish between floral, perfumery, oriental, “green” or “aquatic” notes, as well as fragrances designed for children. Sometimes, however, a composition can be intriguing yet difficult to assign to any particular category. Professionals use a much more sophisticated classification system. The French Society of Perfumers, for example, distinguishes fragrance families such as chypre, leather, woody and citrus.

The use of classic fragrance compositions in cosmetics requires all fragrance allergens present above the legally defined thresholds to be declared in the product’s INCI list, for example Linalool or Citronellol.

One of their major advantages is their relatively low cost compared with other fragrancing methods. In addition, depending on the intended application, suppliers can provide compositions that are soluble in water or oil.

However, working with fragrance compositions also has its drawbacks. One of them is their tendency to thin emulsions, which may need to be compensated for during formulation. Another common issue — particularly with floral compositions — is the tendency to turn water-based products pink, while oriental compositions may cause them to develop a yellowish colour.

ALLERGEN-FREE FRAGRANCE COMPOSITIONS

A significant proportion of consumers are sensitive to common fragrance allergens. In response to this need, fragrance suppliers have developed compositions free from the 26 fragrance allergens listed under Regulation (EC) No 1223/2009.

This does not mean that such compositions contain no ingredients that could potentially cause skin irritation, but their levels are significantly reduced. In the INCI list, apart from Parfum, none of the fragrance allergens will be listed separately.

This approach also has its limitations. The absence of certain key fragrance components — many of which are naturally occurring constituents of citrus oils — makes it impossible to recreate certain types of fragrances.

ESSENTIAL OILS

Essential oils are extracts most commonly obtained by steam distillation of fragrant parts of plants, including flower petals, bark, leaves and fruit peels. They are an extremely popular way of fragrancing cosmetics positioned as natural.

Their completely natural origin is their greatest advantage and one of their key benefits over classic fragrance compositions. It is also worth mentioning that many essential oils possess skin-conditioning properties.

However, they have their drawbacks. The main one is their relatively limited fragrance range. Many consumers who begin exploring essential oils expect rich, sophisticated scents, only to encounter predominantly earthy, resinous and herbal aromas such as patchouli, eucalyptus, basil, juniper, vetiver and sage. In contrast, the number of truly appealing and versatile scents is much smaller — rose, lavender, citrus, cinnamon, ylang-ylang and bergamot, for example.

Another significant disadvantage is the fact that essential oils contain highly concentrated fragrance allergens, which can increase the risk of skin irritation, most commonly manifested as redness and a burning sensation.

Unfortunately, it is not possible to create, for example, a lemon note without using substances responsible for that characteristic scent, such as limonene — which is itself a fragrance allergen from the regulated list.

From a technological perspective, one of the challenges when formulating water-based products such as a “toner with essential oils” is the need to use relatively high levels of solubilizers to obtain a clear solution.

Fragrancing cleansing products such as shower gels and shampoos presents another problem: part of the fragrance can be lost during formulation and storage. Surfactants bind essential oils, making them less perceptible in the bulk of the product. Even more importantly, this effect can become more pronounced over time.

NATURAL FRAGRANCE COMPOSITIONS

This is another nod towards consumers who are constantly looking for new ways to fragrance cosmetic formulations in line with the “green” trend.

Natural fragrance compositions are created partly from essential oils and partly from fragrance ingredients of natural origin. However, creating fragrances that are widely perceived as attractive using these ingredients is an extremely challenging task, as the palette of available raw materials is considerably limited.

We therefore cannot expect a rich range of sophisticated natural fragrances comparable to what can be achieved with synthetic compositions.

In summary, the greatest advantage of this approach is, once again, its natural origin. The drawbacks include the presence of fragrance allergens, relatively “flat” and straightforward scent profiles, and a higher price compared with their synthetic counterparts.

HYDROSOLS

Hydrosols, also known as floral waters, are interesting ingredients that can serve both a fragrancing and a marketing purpose. They should not be confused with extracts, which are obtained through different processes using various parts of plants.

From a technological perspective, hydrosols are essentially the aqueous fraction obtained during steam distillation. The liquid collected during the process is separated into essential oil and the hydrosol fraction.

Contrary to popular belief, not all hydrosols have a noticeable fragrance. In fact, one could argue that most of them do not. Many consumers discover this only after purchasing them, and the fact that jasmine or lotus hydrosol does not smell the way they expected can be a major disappointment. Some of the exceptions include rose, lavender, rosemary, neroli and cedar hydrosols.

Their advantages include their natural origin, the absence of fragrance allergens and unlimited solubility in water, meaning that no solubilizers are required.

However, there is an important technological consideration: achieving a satisfactory level of fragrance in a cosmetic formulation requires a much higher amount of hydrosol. While a fragrance composition may be used at, for example, 0.3%, a hydrosol may need to be added at a minimum of 5–10%. This, of course, has a direct impact on the cost of the formulation.

There is also the question of their limited applicability. Adding 10–15% hydrosol to a hot-process emulsion often means incorporating it into the heated water phase, which inevitably results in the loss of some of its fragrance. For this reason, hydrosols are best suited to predominantly water-based products such as micellar waters, toners and serums.

ABSOLUTES

Absolutes are aromatic extracts containing almost all of the volatile fragrance compounds present in the plant material. They differ from conventional essential oils primarily in the way they are obtained. Classic essential oils are produced by steam distillation, but this method may be unsuitable for extremely delicate raw materials such as jasmine or tuberose.

In such cases, solvent extraction is used, or — increasingly relegated to the past — the traditional enfleurage method, in which solid fats are used to absorb the fragrant compounds.

Absolutes are exceptionally expensive ingredients. For example, only around 12 drops of jasmine absolute can be obtained from one hectare of jasmine plantation. For this reason, they are not normally used directly to fragrance cosmetic formulations — they are simply too concentrated and too costly. Instead, they are used as components of many sophisticated fragrance compositions.

FLORAL WAXES

A refined alternative for lovers of natural ingredients. Floral waxes are obtained as a by-product during the extraction of absolutes. They are fragrant substances in solid or semi-solid form and can be found in INCI lists under names such as Jasmin Sambac Wax.

Occasionally, the cosmetic raw material market offers what might be described as “imitation” floral waxes — conventional essential oils dissolved in a blend of vegetable oils and butters. It is therefore worth checking the origin and composition of the raw material carefully.

True floral waxes are an exclusive way of fragrancing cosmetic formulations, something that is naturally reflected in the final price of the product.

PHENETHYL ALCOHOL

A fascinating ingredient in the world of cosmetics, phenethyl alcohol is a constituent of rose oil and has a fragrance that many people describe as violet-like.

It has also found another interesting application: it possesses preservative properties and, at an appropriate concentration, can completely replace a conventional preservation system in certain types of products.

This makes it particularly attractive to manufacturers for whom a “preservative-free” claim is an important part of their marketing strategy.

IS THERE A PERFECT FRAGRANCING SOLUTION?

Selecting a fragrance composition is a complex process that can have a significant impact on the success of a cosmetic product. It is influenced by the marketing concept — for example, whether the product is positioned as natural or allergen-free — as well as by the manufacturer’s budget, since there is no denying that good fragrances can be expensive.

For a formulator, the process can sometimes feel like a long and winding road. Meeting all the requirements may be difficult, or even impossible. Consider, for example, an allergen-free orange-scented cosmetic, an oil-based product fragranced with hydrosols, or an inexpensive product with a rich, sophisticated oriental fragrance.

Creating an entire product line around a specific fragrance requires a great deal of patience and extensive testing. The same fragrance composition behaves differently in different types of products — a shampoo, cream or body oil — and different fragrance notes may become more prominent as a result.

Unfortunately, there is still no perfect fragrancing solution that can meet the expectations of every consumer.

Zuzanna Fedyczak for "Świat Przemysłu Kosmetycznego" 4/2021 s.324/2021 s. 32