Valerie George, Contributing Editor01.16.23
Dear Valerie: Appreciated your formulation advice in a recent Happi issue. It was quite instructive as to formulation, especially the advice regarding pH stability with the Na-Benzoate/Gluconolactone-preserved lotion. However, Na-Benzoate/Gluconolactone is a very poor preservative system in any product context and at any pH. I think it would be quite vulnerable to gram negative exposure.
—Gram Negative Nelly
Dear Nelly:
Reader feedback is always appreciated! I agree this is a preservative system that has its challenges, but it also does have a time and place where it can be used successfully. It’s not a favorite of chemists, but it is a favorite of marketing, where consumers are demanding alternate preservation systems, even if they’re less robust. I would advise readers to take heed from your note and consider supplementing the system with another preservative.
Dear Valerie: Does the purple colorant in purple shampoos really keep blonde hair from becoming yellow?
—Fading Fast
Dear Fading Fast:
Purple shampoos used to be the secret weapon a hair stylist had for brassy blonde coifs, hidden in the back of the salon. Now, these potent violet-toned products are available all over the retail market, whether you’re shopping for mass, prestige or salon brands. Not only can you get purple in varying shades, from very blue purples to very red purples, brunettes can get blue or green to counteract orange or red tones, respectively.
These shampoos (or conditioners or masks or toners or…) don’t prevent your hair from becoming yellow or orange or red. They simply counteract any color your hair is showing. For example, if you are a platinum blonde, your hair may appear yellow over time as your previous colored toner fades from your hair. The hair hasn’t become yellow, its natural yellow color is being revealed. Applying a purple shampoo will once again deposit purple dyes to the exterior of the hair shaft. Since color is additive, the purple and yellow will combine to give a neutral appearance. Once the purple dyes wash away, hair will look yellow again. It’s the same with orange-plus-blue and red-plus-green; these are complementary colors and chemists are just using basic color theory in the shampoo to help stylists and consumers neutralize their unwanted warmth.
The most classic dye to use is Ext D&C Violet 2, also known as Acid Violet 43. This dye is readily water soluble and has a mild affinity to the hair fiber. It is too large to penetrate the hair but will coat the outside of the hair fiber temporarily. You can also achieve a purple tone by combining basic dyes, such as Basic Red 51 and Basic Blue 99. Colorants are highly regulated for safety in use, so make sure to check the regulations for wherever the product will be sold. Also, when formulating, keep in mind a little bit of dyes goes a long way.
Dear Valerie: I’m trying to formulate some cleaning products (shampoos, hand wash, facial cleanser) and I have to avoid any traditional, chemically-synthesized surfactants. I’ve been hearing about biosurfactants lately as alternative surfactant systems that provide the same or better cleaning properties. Have you heard of these?
—Bio Bob
Dear Bob:
Biosurfactants are not to be confused with bio-based surfactants, of which there are plenty on the market. Biosurfactants are essentially microbial-produced surfactants, where the surfactant has been created by microorganisms like bacteria or yeast through fermentation. They can be amphipathic in nature, like a true surfactant, reducing the interfacial tension between aqueous and lipophilic phases, and behave as a cleansing agent. I first learned about biosurfactants in 2012 as an industry neophyte, when Fraunhofer IBG announced its quest to produce cleansing agents from yeast and bacteria. However, biosurfactants have been on the market for much longer, with patents going back to the late 1970s. Since this first encounter during my early days in the industry, I have had the pleasure in partaking in numerous meetings with raw material vendors to learn about the chemistry going back to 2015.
Biosurfactants—as we know in personal care—are glycolipids, which can be further classified to rhamnolipids and sophorolipids. You may see all three INCI names in use, with glycolipids being the older, ambiguous China-compliant name.
Rhamnolipids are glycolipids typically produced through fermentation by Pseudomonas bacteria species, with a rhamnose sugar and an oil-like rapeseed as a lipid source contributing a β-hydroxy fatty acid. Sophorolipids are also glycolipids, typically produced via fermentation by Candida yeast, with a disaccharide sophorose and fatty acids from oils like rapeseed or soybean.
Rhamnolipids exist in monolipid or dilipid form, while sophorolipids exist in either an acid or lactone form, or mixtures, thereof. The composition and blend of forms determines the overall HLB and thus the attributes the lipid contributes to the formulation. They can be emulsifiers, wetting agents, solubilizers, degreasers, foam stabilizers or antimicrobial agents, depending on the raw material composition, its activity level and final use level in formulation. Biosurfactants generally tend to be extremely effective at low concentrations in formulation, as they have much lower critical micelle concentrations (CMCs) compared to their traditional surfactant counterparts. This also makes biosurfactants less irritating on skin.
Sodium Surfactin is another interesting biosurfactant that has been used in Japan since 2001. It is not a glycolipid per se (and therefore nor a rhamnolipid or sophorolipid). It’s a hydrophilic, cyclic peptide composed of seven amino acids conjugated with a hydrophobic fatty acid chain, fermented from Bacillus subtilis. This makes Sodium Surfactin a surfactant, capable of emulsifying polar and non-polar oils in a D-phase emulsion (3,000 times more effective than lecithin, according to the supplier), gelling oils into clear gels, and has moderate foaming compared to other surfactants like low-foaming anionics or nonionics.
There is certainly a lot of hubbub about biosurfactants. I predict they’ll be the “it” ingredient of 2023 as brands seek more gentle, biodegradable and green chemistry options in the surfactant space. There is a lot of potential available for chemists with the power of biotechnology, and hopefully the prices become more feasible to allow biosurfactants to be used more widely in personal care.
Valerie George
askvalerie@icloud.com
Valerie George is a cosmetic chemist, science communicator, educator, leader and avid proponent of transparency in the beauty industry. She works on the latest research in hair color and hair care at her company, Simply Formulas, and is the co-host of The Beauty Brains podcast. You can find her on Instagram at @cosmetic_chemist or showcasing her favorite ingredients to small brands and home formulators at simply-ingredients.com.
—Gram Negative Nelly
Dear Nelly:
Reader feedback is always appreciated! I agree this is a preservative system that has its challenges, but it also does have a time and place where it can be used successfully. It’s not a favorite of chemists, but it is a favorite of marketing, where consumers are demanding alternate preservation systems, even if they’re less robust. I would advise readers to take heed from your note and consider supplementing the system with another preservative.
Dear Valerie: Does the purple colorant in purple shampoos really keep blonde hair from becoming yellow?
—Fading Fast
Dear Fading Fast:
Purple shampoos used to be the secret weapon a hair stylist had for brassy blonde coifs, hidden in the back of the salon. Now, these potent violet-toned products are available all over the retail market, whether you’re shopping for mass, prestige or salon brands. Not only can you get purple in varying shades, from very blue purples to very red purples, brunettes can get blue or green to counteract orange or red tones, respectively.
These shampoos (or conditioners or masks or toners or…) don’t prevent your hair from becoming yellow or orange or red. They simply counteract any color your hair is showing. For example, if you are a platinum blonde, your hair may appear yellow over time as your previous colored toner fades from your hair. The hair hasn’t become yellow, its natural yellow color is being revealed. Applying a purple shampoo will once again deposit purple dyes to the exterior of the hair shaft. Since color is additive, the purple and yellow will combine to give a neutral appearance. Once the purple dyes wash away, hair will look yellow again. It’s the same with orange-plus-blue and red-plus-green; these are complementary colors and chemists are just using basic color theory in the shampoo to help stylists and consumers neutralize their unwanted warmth.
The most classic dye to use is Ext D&C Violet 2, also known as Acid Violet 43. This dye is readily water soluble and has a mild affinity to the hair fiber. It is too large to penetrate the hair but will coat the outside of the hair fiber temporarily. You can also achieve a purple tone by combining basic dyes, such as Basic Red 51 and Basic Blue 99. Colorants are highly regulated for safety in use, so make sure to check the regulations for wherever the product will be sold. Also, when formulating, keep in mind a little bit of dyes goes a long way.
Dear Valerie: I’m trying to formulate some cleaning products (shampoos, hand wash, facial cleanser) and I have to avoid any traditional, chemically-synthesized surfactants. I’ve been hearing about biosurfactants lately as alternative surfactant systems that provide the same or better cleaning properties. Have you heard of these?
—Bio Bob
Dear Bob:
Biosurfactants are not to be confused with bio-based surfactants, of which there are plenty on the market. Biosurfactants are essentially microbial-produced surfactants, where the surfactant has been created by microorganisms like bacteria or yeast through fermentation. They can be amphipathic in nature, like a true surfactant, reducing the interfacial tension between aqueous and lipophilic phases, and behave as a cleansing agent. I first learned about biosurfactants in 2012 as an industry neophyte, when Fraunhofer IBG announced its quest to produce cleansing agents from yeast and bacteria. However, biosurfactants have been on the market for much longer, with patents going back to the late 1970s. Since this first encounter during my early days in the industry, I have had the pleasure in partaking in numerous meetings with raw material vendors to learn about the chemistry going back to 2015.
Biosurfactants—as we know in personal care—are glycolipids, which can be further classified to rhamnolipids and sophorolipids. You may see all three INCI names in use, with glycolipids being the older, ambiguous China-compliant name.
Rhamnolipids are glycolipids typically produced through fermentation by Pseudomonas bacteria species, with a rhamnose sugar and an oil-like rapeseed as a lipid source contributing a β-hydroxy fatty acid. Sophorolipids are also glycolipids, typically produced via fermentation by Candida yeast, with a disaccharide sophorose and fatty acids from oils like rapeseed or soybean.
Rhamnolipids exist in monolipid or dilipid form, while sophorolipids exist in either an acid or lactone form, or mixtures, thereof. The composition and blend of forms determines the overall HLB and thus the attributes the lipid contributes to the formulation. They can be emulsifiers, wetting agents, solubilizers, degreasers, foam stabilizers or antimicrobial agents, depending on the raw material composition, its activity level and final use level in formulation. Biosurfactants generally tend to be extremely effective at low concentrations in formulation, as they have much lower critical micelle concentrations (CMCs) compared to their traditional surfactant counterparts. This also makes biosurfactants less irritating on skin.
Sodium Surfactin is another interesting biosurfactant that has been used in Japan since 2001. It is not a glycolipid per se (and therefore nor a rhamnolipid or sophorolipid). It’s a hydrophilic, cyclic peptide composed of seven amino acids conjugated with a hydrophobic fatty acid chain, fermented from Bacillus subtilis. This makes Sodium Surfactin a surfactant, capable of emulsifying polar and non-polar oils in a D-phase emulsion (3,000 times more effective than lecithin, according to the supplier), gelling oils into clear gels, and has moderate foaming compared to other surfactants like low-foaming anionics or nonionics.
There is certainly a lot of hubbub about biosurfactants. I predict they’ll be the “it” ingredient of 2023 as brands seek more gentle, biodegradable and green chemistry options in the surfactant space. There is a lot of potential available for chemists with the power of biotechnology, and hopefully the prices become more feasible to allow biosurfactants to be used more widely in personal care.
Valerie George
askvalerie@icloud.com
Valerie George is a cosmetic chemist, science communicator, educator, leader and avid proponent of transparency in the beauty industry. She works on the latest research in hair color and hair care at her company, Simply Formulas, and is the co-host of The Beauty Brains podcast. You can find her on Instagram at @cosmetic_chemist or showcasing her favorite ingredients to small brands and home formulators at simply-ingredients.com.