The
Wrap

How Much Heat is Too Much Heat for your Hair? These Scientists are on the Case.

It’s a thought that has likely crossed your mind, mid-flat iron: “How much damage is this really doing to my hair?”

A team of researchers at Purdue University in Indiana is on a mission to answer this very question. Engineering professor Tahara Reid had been curious about the effects of heat on African-American hair since she was in graduate school, so she teamed up with another engineering professor, Amy Marconnet, in August of 2013 to study a (surprisingly!) under-researched area: the damage done by heat on different hair types.

We chatted with Jaesik Hahn, a graduate student in Reid and Marconnet’s heat lab, about the results they released this year, his hopes for the research and why he’s so motivated to figure out how much heat is too much. Here are three lessons we learned:

1. Different types of hair respond differently to heat.

While we were hoping Hahn would give us exact recommendations on how hot to set our curling irons, he explained that it’s just not that simple. The cornerstone of their research is the discovery that different hair types respond differently to heat, he says. But understanding the exact nature of those differences, is where the scientists have their work cut out for them.

Unfortunately, “we don’t know yet whether different types of hair are negatively or positively correlated with thermoconductivity; we just know they’re different,” Hahn explains. For that, they’re continuing their research in the realm of thermodiffusivity, or how quickly heat moves through hair fibers.

“The goal is to try and understand if different types of hair have different thermal diffusivities,” says Hahn. “We want to explain why people of different hair types experience different degrees of heat damage — even if they’re using the same hair products.”

“We want to explain why people of different hair types experience different degrees of heat damage — even if they’re using the same hair products.”  

2. Preconditioning might help prevent damage — but it might not.

It’s a commonly held “truth” in the beauty industry that the more hair is more moisturized, the less prone it will be to breakage at the hands of a straightener. But the researchers say there’s no actual, scientific proof that this is true. Says Hahn: “We know some people believe that moisturizing their hair might help protect from heat damage, and there’s rationale there. But we haven’t seen any validation of it, so we’re working to see if that’s the case.”

The team is conducting experiments that measure relative humidity in the environment to determine if it affects hair’s thermal properties. But for now, the jury’s still out on whether pre-moisturizing does help prevent damage — though we’ll keep conditioning anyway.

 

3. Understanding your hair is the first step in appreciating your own beauty.

No matter the results of their research, Hahn says that one goal has kept the team motivated throughout: education. To date, most scientific studies of hair have focused on Caucasian hair, he says. As a result, “there isn’t any established knowledge or fundamental understanding of different hair types,” he says. 

For the Purdue team, this lack of information has pushed them to help women understand their hair, their decision-making — and their identities.

"African-American women have treated their hair with methods that were originally developed for hair very different from their own — sometimes based on standards of beauty that didn’t include them."

“African-American women have treated their hair with methods that were originally developed for hair very different from their own — sometimes based on standards of beauty that didn’t include them,” Hahn says. “Understanding their hair is an important step in appreciating their own beauty.”