79 Silicone Alternative Solutions in Personal Care
stearyl ether or PPG-14 butyl ether are used together with hydrocarbons, depending on the
most important needs of the formulator (including costs and sensorial aspects).
In hair oil formulations, large quantities (70–95%) of cyclic D5 are used to dissolve high
molecular weight, high-viscous dimethiconol or other silicones. Due to the high volatility
of D5, this is an elegant way to treat the hair with small amounts of these heavier silicones,
avoiding hair that feels and looks greasy. In addition to this, the high molecular weight
silicones act as rheology modifiers, i.e., to thicken the flow behavior of the final product.
Viscous hair oil formulations are needed for consumers to apply the product more easily
and to avoid the aspiration of the hair oil by the consumer. Therefore, to react to the
imminent D5 ban, substituting cyclic silicones requires alternative solutions to dissolve
high molecular weight silicones. Besides very low molecular weight dimethicones, volatile
hydrocarbons (e.g. (iso)dodecane, undecane, tridecane, isohexadecane) can be used as solvents
giving similar properties. Another silicone alternative option is replacing them with lighter
emollients like dicaprylyl carbonate, coco-caprate, or dicaprylyl ether in hair oil sprays.
CHALLENGES AND ATTEMPTS IN REPLACING LOW MOLECULAR WEIGHT
(LINEAR) SILICONES
Dimethicones are utilized in skin care applications for two primary reasons. Firstly, they
serve as conventional emollients that impart the desired sensory profile to the formulation,
resulting in a pleasant, waxy, slippery, and light silicone-like skin feel. In this regard,
lighter dimethicones with viscosities ranging from 1 to 50 cSt are employed as sensory-
inducing emollients, and they are typically incorporated in significant quantities.
The second function of silicones is to act as anti-soaping or anti-whitening agents. Certain
ingredients widely used in cosmetics, such as fatty alcohols or biopolymers, can enhance a
whitening effect when the emulsion is rubbed on the skin due to foaming. This undesired
effect is perceived as unpleasant by consumers. However, by incorporating a small amount of
a silicone into the formulation, the whitening effect can be eliminated. It is important to note
that the quantity required to achieve the anti-whitening or anti-soaping effect is significantly
lower than what would be used with a conventional emollient. Including larger amounts of
heavier dimethicones in skin-care emulsions can result in a greasy and sticky sensory feel.
With growing consumer awareness for sustainability aspects, and brands preparing for
potential regulatory bans on all types of silicones, a dimethicone-free trend is rapidly
gaining momentum. Formulators are faced with the challenging task of finding natural
and high-performing alternatives to dimethicones, often working within tight timeframes.
In the present section, light dimethicones that are commonly used in skincare for their
sensory benefits will be the focus. The initial step in this process involves identifying
natural-based emollients or mixtures that can match the sensory and physicochemical
performance properties of dimethicone at the emollient level. This can be achieved by
combining emollients with different properties, such as varying polarities, spreading
values, viscosity, and sensory characteristics. By doing so, formulators can attain a good
level of flexibility in terms of potential replacements.
However, it is worth noting that the process of selecting the appropriate emollient and
determining the ideal ratio to mimic the performance of dimethicone can be quite daunting.
The intricate nature of this decision-making process adds an additional layer of complexity
to the formulation development journey.

80 JOURNAL OF COSMETIC SCIENCE
Assume that a formulator has narrowed down the potential replacements to only a few
candidates based on their experience, supply, and cost guidelines. However, in reality, the
number of potential options could be significantly higher. It is unlikely that any single
emollient among these candidates on its own would be a perfect match to dimethicones.
The number of potential binary or ternary mixtures that could match the performance
of dimethicones can easily become very large. It is important to note that no formulator
would explore all possible candidates, as it would be extremely time-consuming and
expensive. However, it is highly likely that the ideal natural-based candidate to replace
dimethicones is present within these possible mixtures. Therefore, it is evident that one
needs an alternative method to capture potential candidates.
An effective approach to overcome this challenge is to leverage digitization, scientific
modeling, and the benefits derived from enhanced computing power. One such option
is Emollient Maestro12, a digital service that can be utilized to identify natural-based
candidates as replacements for a wide range of synthetic silicones, including D5 and
dimethicones with viscosities ranging from 1 to 200 cSt, mineral oils, and hydrocarbon-
based emollients such as isododecane, isohexadecane, squalene, and many more.
The algorithm powering Emollient Maestro employs prediction and optimization models
that theoretically explore all possible emollient combinations and then return the best ones
that match a given synthetic dimethicone benchmark. This service offers a highly efficient,
quick, and cost-effective solution for formulators to identify potential replacements for
dimethicones and other synthetic emollients.
Figure 2 illustrates the emollient-level performance profiles of dimethicone 5 cSt, which is
commonly used in skin care emulsions for its sensory benefits, and an optimized natural-
based emollient mixture of dicaprylyl carbonate, dicaprylyl ether, and undecane/tridecane
(ratio 1.7:3.2:1) obtained from Emollient Maestro. The left panel in Figure 2 shows an
overlapping physico-chemical profile of the silicone (which was experimentally measured)
versus the natural-based emollient mixture (which was predicted). In this panel, various
properties that formulators consider when selecting a new ingredient, i.e., viscosity,
Figure 2. Physico-chemical (left) and monadic sensory (right) comparisons between dimethicone 5 cst
(experimentally measured) and a natural-based emollient combination recommended by Emollient Maestro
(prediction), exhibiting a good agreement at the emollient level.