The truth about silk and cashmere proteins

Laura`s Questions:

Question 1:

Products such as Softsoap’s Pure Cashmere line claim to contain a cashmere extract, taken from protein in goat hair oil. Does this sound plausible?

Answers From The Right Brain:

Yes, it’s plausible. Protein is a natural ingredient derived from animals (from skin, hooves, horns, and hair) and from vegetables. Cashmere extract belongs to the class of proteins extracted from animal hair; goat hair to be precise. In fact, goats have two layers of hair and the softer, inner hair is what we know as cashmere. The technical name for this ingredient is hydrolyzed keratin (sometimes called hydrolyzed wool. I’ll explain what hydrolyzed means in a minute.)

Question 2:

Some products contain hydrolyzed silk protein. Is this product common in hair products?

Answer: Yes, many cosmetic products use silk protein as a featured ingredient. And silk protein, as the name implies, is extracted from silk. As in silk worm cocoons. Or spider’s silk.

Question 3:

What benefits would the cashmere extract likely have? Would it prevent moisture loss? Soften skin? Would this cashmere be considered an oil?

Question 4:

What specifically does silk protein do? (I’ve read it temporarily fills cracks in the hair shaft, but I’m not sure what this means.) Would this silk protein have a sealing effect on dry skin? If so, how and why?

Answers: Here’s where it gets tricky. In theory, proteins can help moisturize skin and smooth hair because hair and skin are also made of protein and because proteins are large molecules that are able to form films. By forming a film they can retard moisture loss, much like the skin that forms on pudding.

However, in practice, proteins are not very effective moisturizing ingredients. That’s because in their native form, they are very large molecules and they are not easy to incorporate into body washes or shampoos. So, the chemical companies that sell proteins have to break them down into smaller units that are more water soluble and therefore easier to work with. This process of breaking big proteins into smaller pieces is called “hydrolysis.” The good news is hydrolyzed proteins are easier to put into formulas. The bad news is, they aren’t very effective because making the molecules smaller causes them to lose much of their film forming properties.

Another reason that proteins aren’t very effective is that they won’t stick to hair very well from a rinse out product (like a shampoo or a body wash.) There are special proteins (called quaternized proteins) that are chemically modified so they’ll stick to hair and skin better.

Does all this mean that Softsoap and other products that use proteins don’t really moisturize hair and skin? No, not at all. It just means that the proteins are not really the functional ingredients doing the moisturizing. That’s a common game that the cosmetic industry plays. Manufacturers try to differentiate their products with “sexy” sounding ingredients. In reality, it’s usually the formula as a whole, and not any specific ingredient, that’s getting the job done.