A Look at Oat Flour for Thickening Fine Hair

Hair Liberty’s Nicole Harmon, our Resident Cosmetic Chemist, is answering your most urgent hair questions. Got one for her? Email me at contests@curlynikki.com using “Hair Liberty” in the subject line and she may answer your question right here on the blog.

CN asks: I’m seeing this oat flour thickening conditioner recipe all over the interwebs. Does it really work?

Nicole answers: Oat flour usually contains around 20% protein, which is twice the amount of protein in all-purpose flour. Hair is made of keratin protein so many conditioning treatments contain small pieces of keratin and other types of protein to reinforce the hair. Oat protein has a relatively high molecular weight which means its particles are usually too big to penetrate through the hair’s outer cuticle layers to give it strength. Instead, oat proteins form a coating on the outside of the strand to make your hair look and feel thicker.

So, oat protein thickens the hair and oat flour contains 20% protein…we have a winner, right? Well, not exactly. Here’s what happens: You make a special oat flour conditioning mixture, put it on your hair, leave it for some amount of time, and then rinse. No matter how long you left the treatment on (even if you sat under the dryer), the oat flour and all of its protein will rinse down the drain. The scientific measurement for how well something can stick to your hair or skin is called “keratin substantivity”. You can’t get the thickening benefits of oat protein from an oat flour treatment because the protein in oat flour has low keratin substantivity. In contrast, henna for example is highly substantive to keratin. Have you ever had orange nails and fingers for days after your henna treatment? The henna’s naturally high substantivity makes it stick to your skin and hair during the rinse phase and for many washes after that.

To experience the natural thickening power of oat protein, you need help from science to increase its substantivity to be more like henna. Look for products that contain “hydrolyzed oat flour”, “hydrolyzed oat protein” or “avena sativa”. Also seek out products that contain panthenol because it thickens the hair similarly to hydrolyzed oat protein. Check out this slideshow from the Good House Keeping Research Institute to see how popular thickening products performed in tests where individual hair strands were measured using lab equipment.