These days, there’s greater emphasis on what exactly is in the products we use, how ingredients are sourced, and what local and global impact there is on the environment. Natural ingredients are increasingly popular with consumers, oftentimes perceived as safer. In addition, people continue to become more concerned about their carbon footprint and impact on the environment. Being “green” is no longer a trend, but a lifestyle choice for many and his is reflected in the products they purchase.

Generally, consumers perceive natural ingredients as safer and better for their health. However, some consumers, particularly Generation Z consumers, are more aware of the impact that the demand for natural ingredients can have on our planet. Among consumers aged 18-44, 33% agree that they’d be willing to pay more for products containing sustainable ingredients, as part of their effort to reduce their carbon footprint [Mintel GNPD]. As a result, sustainable sourcing of natural ingredients is a growing part of the movement toward ingredient transparency, with consumers now looking to understand the supply chain of natural ingredients to ensure ethical sourcing.

‘Free From’ Formulations

For skin care leave-on formulations, there has been increasing importance placed on ensuring emulsions are made with more natural, sustainable ingredients. More consumers desire products that are free from ethoxylated emulsifiers and silicones. With the industry increasingly moving toward these “free from” formulations, challenges can arise when attempting to make them stable and aesthetically pleasing. At times, it is difficult to create the same aesthetic profile in a silicone-free emulsion compared to those with silicones. Emulsifiers have a critical impact on the stability and the aesthetics of a formula. Here are some key parameters to consider when choosing emollients and emulsifiers for “clean” skin care products.

Emollients

Silicones lend a nice application with a dry after-feel to formulations. This is true for formulation types including skin care face and body creams, foundations, BB creams and others. Silicones tend to have quick absorption and provide a dry powdery after-feel with low tackiness. However, cyclic silicone ingredients have been effectively banned in Europe for use in rinse off products as of January 2020, with potential to cover leave-on products as well in the future. With all the negative press around cyclic silicones, many finished goods manufacturers have opted to replace silicones with what are perceived to be cleaner more sustainable ingredients.

Cyclomethicone is synthetic and belongs to the category of persistent, bioaccumulative and toxic chemicals. There are other options available with similar application and aesthetic benefits that are 100% natural and biodegradable (Share of C-atoms from renewable sources (ISO 16128-2)). Two alternatives are available on the market: Undecane (and) tridecane, which combined make for an ultrafast spreading alternative, for a naturally-derived, fresh, dry, and volatile carbon-based emollient. It is a clear liquid similar to cyclomethicone and is readily biodegradable. Another option: Coco-Caprylate, is also a quick spreading emollient and is 100% naturally-derived. Cyclomethicones perform additional functions in emulsion formulations, such as pigment wetting. The two alternatives mentioned offer superior pigment wetting performance, in addition to superior color and UV filter stability versus cyclic silicones. This is of utmost importance for both skin care and color formulations. While cyclic silicones offer both aesthetic and functional benefits in formulations, many of the greener options offer the same if not better performance, making it possible to create silicone-free formulations that feel just as nice and are just as stable as the formulas containing silicones.

Like their cyclic siblings, linear silicones can enhance the application and after-feel of skin care and color formulations. However, they are also synthetic and are non-biodegradable. The challenge becomes replacing these ingredients with more sustainable and biodegradable options, while still achieving the silky, powdery, light aesthetic of these silicones. There are several options currently on the market that can help to fill this void. Dicaprylyl carbonate is one such option. It is a multifunctional ingredient that yields a dry and cushiony after-feel. Another option for consideration is dicaprylyl ether. This silicone replacement has a very light feel, yielding both a cushiony and waxy dry after-feel, as well as has the benefit of pH stability, which allows for diverse types of products to be formulated such as those containing alpha hydroxy acids for skin benefits. Formulating products free from both cyclic and linear silicones is certainly possible with the options mentioned here.

Consumers don’t have to compromise on their desire for all-natural products that meet their high-performance standards. Taking these steps in creating “free-from” formulations will help make products that are better for both the skin and the environment. Many of the natural silicone alternatives on the market have been certified by well-known certifying agencies such as Cosmos, Ecocert and the Natural Products Association, and offer an indication of naturalness according to ISO 16128. Traditional silicones do not hold any of these certifications.

Emulsifiers

Although there are benefits to using ethoxylated and PEG emulsifiers, the cosmetic industry is certainly trending toward removing these from formulations due to 1,4-Dioxane concerns. There are many options on the market that are ethoxylate and PEG free, are more natural and biodegradable, and still offer stability, processing and sensorial benefits. Polyglyceryl-based emulsifiers are strong, clean emulsifiers. They are made by polymerizing glycerin via an ether group. These emulsifiers can be used for both oil-in-water or water-in-oil emulsions depending on the HLB. For example, two such lower HLB (hydrophilic/lipophilic balance) options are polyglyceryl-2 dipolyhydroxystearate and polyglyceryl-3 diisostearate. These are suitable for water-in-oil emulsions and are also helpful for pigment wetting in anhydrous color formulations. Higher HLB polyglyceryl-based emulsifiers on the market include Polyglyceryl-10-Laurate, which is suited for oil-in-water emulsions. Glucoside based emulsifiers are also a great option for clean and “free-from” formulations. Lauryl glucoside (and) polyglyceryl- 2 dipolyhydroxystearate (and) glycerin is one example. Glucoside-based emulsifiers are developed from sugars, and therefore are naturally derived. Cetearyl glucoside (and) cetearyl alcohol is an example of a natural self-emulsifying cream base, which demonstrates great skin compatibility, even with sensitive skin. This technology, based on alkyl polyglucoside chemistry, builds biomimetic lamellar creams that exhibit the same lamellar structure as natural skin lipids. It is efficient at low dosages and helps to create light and natural emulsions.

Additional chemistries on the market include glyceryl, sorbitan and sucrose-based esters. Although ethoxylated and PEG emulsifiers have some formulation benefits, ingredient innovation has given the industry alternative modern emulsifiers that are just as effective in formulation, cleaner for the environment and milder for skin. High stability parameters are indeed achievable—the ratio in formulation (oil/water ratio) will just need to be more specific and accurate, since the oligomer distribution is not present as it is with ethoxylates.

In the next section, we will tackle how to formulate a cleanser while considering some of the major trends in the market: sulfate-free, PEG-free, EO-free, 1,4-Dioxane-free. We will look at the different chemistries that make up a shampoo, body wash and face wash, and then provide guidelines for chemists to get started on the bench.


Surfactants

Anionic surfactants, such as fatty alcohol ether sulfates and fatty alcohol sulfates, represent the majority of primary surfactants. They provide superb cleansing and excellent foam properties that include quick flash foaming, large lacey bubbles with an abundance of foam volume and stability. They can be easily thickened with salt and are economical. Ethoxylation is a chemical process in which ethylene oxide is reacted in desired molar ratios with an alcohol or acid or triglyceride oils to produce surfactants. During the process of ethoxylation, trace amounts of 1,4-Dioxane and residual ethylene oxide can be left in the product. In December 2019, New York Governor Andrew Cuomo signed into law legislation (S4389B/A6295A) to limit 1,4-Dioxane to 1ppm in personal care products, and 10ppm in cosmetic products, by December 31, 2023.

There are some perceived negative effects of using these anionic surfactants, especially on color treated hair. Permanent hair color works through tiny oxidative dye molecules that penetrate the cortex and provide instantaneous change. However, they easily leach out of the hair and cause change in color and tone. In addition to accelerating color fade, these anionic surfactants tend to over-strip the hair and skin, which leaves hair and skin feeling squeaky clean. Hair is left dry and difficult to comb and skin is left feeling tight, dry and lacking moisture. Consumers who invest in hair coloring seek to maximize color longevity and look for safer and milder options that avoid sulfates, ethoxylation and 1,4-Dioxane.

Fortunately, there are some practical and first-rate solutions for consumers. The first more gentle, milder alternative surfactant chemistry is alkyl polyglucoside (APG). These nonionic, sugar-based surfactants combine naturalness with the mildness needed in body wash and baby wash products, as well as give shampoos the rich and dense foaming qualities consumers desire. These are made from 100% renewable, plant-derived feedstocks. APGs improve skin compatibility when used with conventional surfactant systems and are especially suited for sensitive skin. This chemistry is just as efficacious in cleansing dirt as SLES, with the additional benefit of exceptional mildness in personal care applications. These proven benefits are ideal for any type of cleansers that health and safety-conscious consumers desire. Additional alternative surfactant options are sodium cocoyl isethionate, and disodium cocoyl glutamate. They have a high natural origin content and provide good foam generation, medium to small bubble size, mildness to skin and eyes, and a nice soft after-feel.

Some things to keep in mind when transitioning to a sulfate-free system is the impact it will have on foaming and thickening. A higher surfactant concentration is needed to obtain the same amount of foam volume, which can increase overall formulation cost. The challenge of thickening concerns the inefficiency of traditional micellar thickening. In this case, the formulator should look to associative and polymer thickeners.


Rheology Modifiers

Thickeners play a vital role in the formulation because they impact its appearance and flow properties. They enable the products we use every day to serve their purpose, because without adding a thickener, most surfactant blends have the viscosity of water.

There are several readily biodegradable, naturally occurring polymers such as starches or gums that can be considered for thickeners, and one of them is xanthan gum. Xanthan gum is a high molecular weight polysaccharide derived from the fermentation of carbohydrates. It can be used in a wide variety of personal care applications including bath products, and skin and hair care products. Because of its structure, it can provide excellent thickening and stability over a wide pH range with no neutralization needed. Additionally, it is flexible enough to be effective in either hot or cold process formulas. Due to its excellent compatibility with a wide range of surfactants, it is a great option for all types of cleansing applications. Lastly, it offers a nice synergy with algin, an algae-based natural rheology modifier. This combination thickens your system while imparting suppleness to skin and improved manageability to hair.


Conditioning Agents

Polyquaterniums, silicones, cationic guars, cationic/acrylamide copolymers and quaternary ammonium salts are some of the popular conditioning agents used in hair care. They improve the look, feel and manageability of hair. Unfortunately, they do not have the natural profile consumers desire. Some natural alternatives are light, fast-spreading esters and ethers for providing slip and shine, and natural oils and butters for conditioning. One example is coco-caprylate. As mentioned previously, it is a readily biodegradable, light emollient made from 100% natural, renewable feedstocks. This ingredient has been known to increase shine even after 24 hours and provide good wet combability. When you compare it to cyclic siloxanes, coco-caprylate has medium polarity, a high flash point (over 140°C), and a refractive index of 1.437 at 20°C. The refractive index of emollients is an important factor and is positively correlated to hair gloss.


Formulations

Next, consider developing a clean and natural leave-on skin care formulation. It avoids the use of ethoxylated emulsifiers, and instead uses an amino acid-based emulsifier, which is very effective even at lower use levels. Cyclomethicone is replaced by the combination of different natural esters including Coco-caprylate and Coco-caprylate caprate. This formulation also replaces the use of an acrylates-based thickener with the more natural and sustainable vegan xanthan gum thickener. Lastly, the formula contains a natural and sustainably sourced active ingredient with proven efficacy.

Ingredient	Function	% wt
Behenyl Alcohol	Consistency Agent	3.00
Coco-Caprylate/ Caprate	Emollient	4.50
Coco-Caprylate	Emollient	3.00
Sodium Stearoyl Glutamate	O/W Emulsifier	0.10
Water, demin	Solvent	82.70
Xanthan Gum	Rheology Modifier	0.50
Glycerin	Humectant	3.00
Glycerin(and) Nephelium Lappaceum Peel Extract	Active	2.00
pH Adjuster	pH Adjuster	0.20
Water/Sodium Benzoate/Potassium Sorbate	Preservative	1.00

pH Value: (23°C):5.0
Viscosity: Brookfield; RVT, Spindle TB, Helipath; 10rpm; 23°C: 5,000-5,600 cP

Here is an example of a natural, clean formulation that offers all the benefits of a great conditioning shampoo without sulfates, EO, PEGs and 1,4-Dioxane. 

Ingredient	Function	%Wt.
Water, demineralized	Solvent	q.s.
Guar Hydroxypropyltrimonium Chloride	Conditioning Agent	0.2
Xanthan Gum	Rheology Modifier	1.00
Algin	Rheology Modifier	0.15
Decyl Glucoside	Surfactant	13.40
Sodium Lauryl Glucose Carboxylate (and) Lauryl Glucoside	Surfactant	11.00
Coco glucoside (and) Glyceryl Oleate	Conditioning Agent	2.00
Sodium Benzoate	Preservative	1.00
Sodium Chloride	Rheology Modifier	1.00
Citric Acid	pH Adjuster	q.s.

pH Value: (23°C): 5.1; Viscosity: Brookfield; RVT; spindle 5; 10rpm; 23°C; 7,000cp; Appearance: Opaque, off-white.


Conclusion

These formulations have been tested, demonstrating robust stability with desirable benefits for the skin and hair, while using natural alternatives to ethoxylates, PEGs, sulfates, and silicones. We know from our consumer research that consumers who seek “free from” claims also tend to prefer simple formulations. Both of these examples contain 12 ingredients or less, enabling you to meet the consumer demand without sacrificing performance. BASF offers surfactants, emollients, emulsifiers, thickeners, silicone alternatives and actives to support your “free from” formulation needs:

• Emollients—Cetiol Ultimate (INCI: Undecane (and) tridecane), Cetiol C5 (INCI: Coco-caprylate), Cetiol CC (INCI: Dicaprylyl carbonate). • Emulsifiers—Eumulgin SG (INCI: Sodium stearoyl glutamate), Eumulgin VL 75 (INCI: Lauryl glucoside (and) polyglyceryl-2 dipolyhydroxystearate (and) glycerin), Emulgade PL 58/60 (INCI: Cetearyl glucoside (and) cetearyl alcohol). • Surfactants—Plantaren 810 UP (INCI: Caprylyl/capryl glucoside), Plantaren 818 UP (INCI: Coco glucoside), Plantaren 1200 N UP (INCI: Lauryl glucoside), Plantaren 2000 N UP (INCI: Decyl glucoside). • Thickeners—Rheocare XGN (INCI: Xanthan gum), Hydagen 558 P (INCI: Algin). • Hair Care Silicone Alternatives—Plantasil Micro (INCI: Dicaprylyl ether (and) decyl glucoside (and) glyceryl oleate. • Actives—Nephydrat (INCI: Glycerin (and) water (and) Nephelium Lappaceum Peel Extract), Nephoria (INCI: Maltodextrin (and) Nephelium Lappaceum Leaf Extract).  

www.carecrations.basf.us or beautycare-na@basf.com