The right chemistry: some clear answers on frizzy hair

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It all started in Rio de Janeiro in 2003. Women began flooding beauty salons after a new treatment was released that claimed to smooth hair, reduce frizz, add shine and produce silky softness. The “Brazilian keratin treatment” quickly became a rage and spread around the world. Before long, however, it became mired in controversy. Not because he didn’t deliver the goods, but because of what he delivered as well. A dose of formaldehyde, a known carcinogen.

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Understanding the science behind the treatment requires a quick course in hair chemistry. So let’s go ! Hair is made up of a type of protein called keratin formed by cells called keratinocytes in the hair bulb which takes root in the hair follicle, a cavity in the epidermis, the outer layer of the skin. As hair grows, cells fill with keratin and die, so the hair shaft essentially becomes a network of protein molecules. Genetics dictate the specific way keratin molecules come together into three-dimensional structures and it is this structure that determines whether an individual’s hair will be curly or straight.

Proteins are chains of amino acids that can be coiled in different ways. The keratin takes on the shape of a helix, the shape being held together by “hydrogen bonds”, a weak attraction between oxygen and hydrogen atoms in adjacent coils. To complicate matters, these coiled keratin helices are twisted into different shapes due to cysteine, one of the amino acids in keratin, binding to another cysteine ​​fragment in a different part of the chain. Specifically, it is the sulfur atoms of cysteine ​​that form sulfur-sulfur bridges. Changing the shape of hair requires breaking the various bonds responsible for the structure of keratin. With these bonds broken, the chain can move more freely in response to the stresses created by combing or curler placement. If at this stage the bonds responsible for maintaining the structure of the keratin can reform, the keratin, and therefore the hair fibres, will have been definitively remodeled. New hair growth will not be affected.

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Hydrogen bonds are easily broken by simple exposure to water. This is why wet hair can be easily shaped. The heat, like with an iron, will evaporate the water and allow the hydrogen bonds to reform, keeping the hair in its new shape until the humidity kicks in. For the shape to be permanently altered, the sulfur-sulfur bonds must be broken and then reformed after reconfiguration of the keratin molecules. The chemical traditionally used to break these bonds is the rather unpleasant smelling thioglycolic acid. The bonding of the sulfur atoms in their new position is achieved with hydrogen peroxide, an oxidizing agent. In expert hands, the results are generally good, but controlling breakage and bond formation is not easy and timing is critical. Too long exposure to chemicals can damage the hair, and too short exposure can give unsatisfactory results.

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The Brazilian Keratin Treatment smooths the hair without the damage that can be caused by permanent treatments. Wet hair is combed straight through, then infused with a mixture of formaldehyde and short chains of amino acids called peptides, often derived from keratin in sheep’s wool. The formaldehyde forms a bond between the keratin and the added peptides preventing the keratin molecules from returning to their original shape. Additionally, the realigned keratin filaments reflect light very effectively, producing shinier, shinier hair.

So what is the controversy? Formaldehyde is a known carcinogen and respiratory irritant. Carcinogenicity is a legitimate concern for hairdressers who may be frequently exposed, but it is unlikely to be an issue for their clients.

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In response to these concerns, a number of “formaldehyde-free” keratin treatments have been introduced. Sometimes the promotion of these is just plain dishonest. “Methylene glycol” avoids the use of the term formaldehyde, but it is just a solution of formaldehyde in water. “Methanal” and “formaldehyde” are alternative names for formaldehyde. Then there are treatments that really don’t contain formaldehyde, with intriguing names like “hair-botox” or “nanoplasty.” Although there is some science here, it often gets drowned in hype.

There is no actual botox involved, the term is used to conjure up a feeling of smoothness. “Nanoplasty” is a coined and meaningless term meant to deduce some type of breakthrough technology. Usually, the products used are based on hydrolyzed keratin or collagen and certain chemicals other than formaldehyde that bind them to the hair. Glyoxylic acid or glyoxyloyl carbocysteine ​​can do this, and although the term formaldehyde is avoided, these chemicals can, with the heat applied during the procedure, break down and produce formaldehyde, although the amounts are probably insignificant. Recent research has shown that specific peptide sequences that incorporate cysteine ​​residues can bind to keratin without the need for a binding agent. These peptides can be easily made and have the potential to straighten hair without the use of “harsh” chemicals.

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Another interesting technology uses the family of “aminopropyltriethoxysilanes” which can be incorporated into the hair and then harden on contact with water. With trade names such as “Filloxane”, “Intra-Cylane” and “Fibra-Cylane”, these chemicals claim to add volume to hair, reduce frizz and maintain the shape of styled hair.

With the importance people place on the way their hair looks, it’s understandable that there’s a lot of competition between products, each trying to carve out a niche for themselves with inventive formulation. Terms such as nourish, regenerate, re-densify, restore, rebuild and rebalance have no meaning when applied to hair, just like “organic” or “natural”. “Targeting hair DNA” is pure nonsense. Some products are promoted as “chemical-free” and should be avoided if only to send a message to companies about using such a ridiculous phrase that is an affront to science.

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Joe Schwarcz is director of the Office of Science and Society at McGill University (mcgill.ca/oss). He hosts The Dr. Joe Show on CJAD Radio 800 AM every Sunday from 3-4 p.m.