Multifunctional chemistry claims space in personal and home care

Formulation is an intricate practice, straddling science and engineering. In the fast-moving market of personal care—and its close cousin, home care—each ingredient carries its own suite of chemical properties that formulators must balance and harmonize to create a product that is stable, effective, and pleasant to use.

These days, chemical firms that supply molecules to consumer product manufacturers are leaning into the concept of multifunctionality: cramming two or more useful properties into a single ingredient. For consumers, multifunctionals mean shorter ingredient lists that let them feel they understand what they’re putting on their bodies or into their home environments. Formulators benefit from fewer variables in their work. And chemical makers win new sales within expanding parts of the home and personal care industry.

R&D into multifunctionality is starting to yield some cleverly designed molecules. The start-up Skinosive, for example, uses chemical linkers to covalently connect ultraviolet (UV) filters to bioadhesives, creating sunscreen active ingredients that stick to the skin’s outer layer, the stratum corneum.

CEO Benoit Canolle says the multifunctional approach means the UV protection lasts longer, even in water; stays where it’s placed on the skin’s surface; and doesn’t penetrate into the user’s bloodstream—three common concerns with sunscreens. The latter property should help Skinosive win regulatory approval for its ingredients; the amount of a chemical that reaches the blood is a key parameter for the government agencies that control sunscreens.

A suite of fragrance molecules from the specialty chemical maker DSM-Firmenich also uses linkers to make single molecules do multiple things. Straight out of the consumer product bottle, the ingredients in the firm’s Haloscent line deposit well onto target surfaces including cloth, hard surfaces, skin, and hair.

But they don’t smell like much of anything at first. Each linker is designed to cleave in response to a different stimulus: oxygen, light, heat, pH, or the action of enzymes naturally present on the body. The molecules release their fragrances for up to 12 h, a much longer duration than conventional perfuming can normally accomplish. “It changes how perfumers formulate, how we think about time,” says Sabine de Tscharner, a perfumer at DSM-Firmenich.

The first generation of Haloscents combined an anchor and a single fragrance molecule, similar to Skinosive’s approach. Newer versions break into two complementary scents, de Tscharner says. And researchers at the firm have published journal articles on examples that have three or more fragrance moieties in the initial molecule (Helv. Chim. Acta 2024, DOI: 10.1002/hlca.202400046; Angew. Chem. 2007, DOI: 10.1002/anie.200700264)

The linker-based molecules from Skinosive and DSM-Firmenich are just the tip of the multifunctional iceberg, according to Nikola Matic, a specialty chemical analyst at the consulting firm Kline. Over the past 10 years or so, Matic says, he’s seen a steady rise in ingredients marketed as multifunctionals.

One reason behind the trend is a change in where formulation experts work, Matic says. Fewer of these scientists are employed at independent formulation and cosmetic chemistry laboratories, which consumer product makers hire to work on individual projects and product lines. Such labs traditionally have deep benches of experts, reams of closely held empirical data, and experience working with ingredients from a wide range of suppliers.

More and more, chemical makers are bringing such experts on board, Matic says. But once they work for an ingredient producer, the scientists are limited to showcasing what the company’s ingredients can do and helping customers develop formulations they can execute on their own. Other formulation firms have expanded or shifted into contract manufacturing for niche brands, and another cohort of formulators has gone to work for large-scale consumer-product makers.

A more diffuse workforce makes it less likely that all the experts needed to pull off a difficult formulation are in the same place, Matic says. As a result, he says, “You have a trend towards simplification of formulations, and multifunctional ingredients are a clever way to get there.”

This industry trend is in harmony with growing consumer demand for products with simple labels and short, comprehensible ingredient lists. “That's a perception you see commonly in food: the shorter the ingredient list, the healthier the food,” Matic says, and many consumers feel as passionately about what they put in their bodies as they do about what they put on them. “A lot of trends move from one to the other.”

Another driver of the growth of multifunctional ingredients is a bit more slippery: they can add a function that the product manufacturer doesn’t want to emphasize or even acknowledge.

Preservation is the most common quality to sneak in through the back door. Brands want their lotions and potions to be shelf stable, so they include preservatives to kill microbes or inhibit their growth. Most product types should stay fresh for 1–2 years under normal storage conditions, according to Lynna Pili, marketing manager for home and personal care in North America for the specialty chemical maker Clariant.

But consumers are increasingly wary of preservatives, especially in the high-end and ecofriendly parts of the market, Pili says. Preservatives also face some of the strictest regulations among personal care ingredient categories.

An ingredient that acts a moisturizer but also boosts the activity of preservatives, for example, lets formulators use less of the troublesome biocides, according to Pili. The firm’s Nipaguard SCE uses sorbitan caprylate to do just that, she says, reducing water loss from the skin while boosting benzoic acid’s microbe-fighting prowess.

Antimicrobial activity is a useful quality for an ingredient to bring to the table one way or another, says Daniela Peters, global marketing director for Evonik Industries’ preservative business. The firm launched a skin care ingredient called Dermosoft GPT MB (glyceryl sesquipelargonate) in Amsterdam this year at In-Cosmetics Global, a major personal care ingredients conference, in May. The ingredient is formally a wetting agent but has its own antimicrobial activity against bacteria and yeast, along with an ability to mask malodor—two side benefits emphasized in the product’s marketing material.

After preservation, one of the most popular bonus functions of a multifunctional is enhanced sun protection, Matic says. Skin care brands are happy to tout the ability of their products to block harmful solar radiation, a quality expressed as sun protection factor (SPF). But in the US, UV filters are regulated as over-the-counter drugs, a tight approval regime that has prevented any new sunscreen molecules from entering the US market since 1996.

The level of regulation an ingredient faces can depend on subtle differences in wording. Saying a film former also happens to boost SPF wouldn’t trigger the need for US Food and Drug Administration clearance as a drug; selling it as a UV filter would. A similar dynamic plays out in preservation. Who’s to say which function—the headline function or a secondary one—really drives the sale to a product maker?

When the net effect is products that don’t go bad and do reduce the prevalence of skin cancer, no one complains about skirting the regulatory edges. The materials involved are legally and properly on the market, after all. “Some of them are really nice ingredients,” Matic says. “You have beeswax; that can indirectly boost SPF. I think beeswax is relatively well regarded.”

Sometimes the secondary claim can be environmental instead of functional. Biodegradability and biobased content can be marketable qualities, says Lauren Leonard, global market development manager for personal care at Eastman Chemical. In a recent survey by the company, she says, 68% of consumers said they would pay more for color cosmetics that are biodegradable.

That result supported Eastman’s decision to enter the color cosmetics market with Esmeri CC1N10, which debuted earlier this month at Suppliers’ Day, an annual personal care conference held in New York City by the New York Society of Cosmetic Chemists. The product is an esterified cellulose powder that acts as a filler, texturizer, and spreading aid for lipstick, foundation, and pressed powders.

Eastman has been modifying cellulose since the invention of photographic film in the 1920s, Leonard says. The challenge in personal care is maintaining cellulose’s biodegradability while installing the chemical moieties that let it perform.

Most multifunctionals combine closely related functions, Matic says, to the point that some ingredient suppliers are just fleshing out their descriptions of existing molecules to get in on the trend. A surfactant that adds lubricity checks the multifunctional box, but surfactants are always slippery. And crowing about a film former with both emollient and skin-barrier properties ignores the fact that emollients, by definition, moisturize by forming a barrier to trap moisture in the skin.

At times, old molecules are rebranded with new functionality. Antioxidants aren’t in vogue now like they were a few years ago, Matic says, but molecules that block blue light and fight environmental stress are in. “It’s the same molecule,” he says. “Very often, the antioxidant property of the molecule is what you’re using.”

And then there are the molecules that really do have multiple, wildly disparate functions. Richard Lock, chief operating officer at the biosurfactant maker Holiferm, says the firm sells its sophorolipids mostly as cleansing and foaming surfactants for home, personal, and oral care products. But he’s been reading academic research suggesting that eating sophorolipids helps chickens digest lipids and fight off protozoan parasites (Animals 2022, DOI: 10.3390/ani12050635; Poult. Sci. 2022, DOI: 10.1016/j.psj.2022.101944).

Biosurfactants can already claim to cleanse, foam, and biodegrade. As trendy as multifunctionality may be, Lock says, Holiferm has no immediate plans to add chickens to the firm’s marketing.