Hair care products have been used for centuries to treat all sorts of ailments, from arthritis to acne.
But for decades, scientists have been wondering whether some of the products we use daily could be harmful.
A new study published in the Journal of the American Academy of Dermatology suggests that there is reason to be concerned.
“For the first time, we show that the active ingredients in many of these products can trigger human keratinocyte injury, leading to loss of hair,” says lead author Dr. Shih-Chuan Chen, an assistant professor of dermatology at New York University Langone Medical Center.
Her team’s study was a collaboration between the University of Southern California, the Johns Hopkins University and Johns Hopkins Medicine.
“What we have found is that these products are actually not safe for humans,” she says.
“There’s a risk of human keratosis induced by the chemicals used.”
The team studied products made by brands such as Neutrogena, Nivea and Oribe, as well as some by the hair care giant L’Oreal.
The researchers analyzed the chemicals in the products, including hair follicles.
They found that the chemicals could cause keratinocytes in the skin to become damaged.
When the hair follicle is damaged, the keratin coats the outer layers of the skin, causing damage to the cells’ surface.
These cells are called keratinosomes.
In the skin’s outermost layer, called dermis, there are cells called keratoblasts, which are made of keratin.
They can then convert their chemical energy into electrical impulses called electrophysiological signals that can be used to stimulate and direct hair growth.
The signals are then used to control the hair’s growth, and can be manipulated to alter the structure of hair follicular cells.
Hair follicles are made up of many individual hair follules, which produce the signals.
They are connected by a thin membrane called a hair follicule tract.
“The process of turning these signals into electrical signals is what makes them so powerful,” says Chen.
“This is why they can cause damage to keratin and to other cells within the hair,” she adds.
“So, we know that they can damage keratin cells.”
Hair follicle damage can be fatal.
But what if the chemicals are just a tiny part of a larger problem?
In this study, the researchers found that a very small number of the chemicals they tested did cause damage.
In fact, there was almost no evidence that these chemicals were causing harm to the human hair follisicle.
“We think that the problems are not in the chemicals themselves,” says Dr. Joseph Zimring, a professor of pediatrics at the University College London, UK.
In other words, it’s not that we don”
These signals, if we don’t address them, we can’t control the growth of our hair,” he says.
In other words, it’s not that we don