How to keep your hair healthy, according to science
Canadians spend more than $2 billion a year on hair care products and salons. We are obsessed with our hair.
In Hairy Tales, a documentary from The Nature of Things, co-hosts Sarika Cullis-Suzuki and Anthony Morgan meet doctors, geneticists, leading researchers and even a Guinness World Record holder for the heaviest weight lifted with hair to explore the fascinating science of hair.
Unfortunately, there's no golden rule to guarantee lustrous locks. Hair health and growth is a complex science, influenced by your unique genes, immune system, hormones, stress level, diet, medications and more.
But there are some things you can do — based on science and common sense — to help maintain your mane.
Feed your follicles
While there's no secret recipe for healthy hair, eating a well-balanced diet makes a difference.
"Just like nutrition is important for your body, nutrition is important for your hair," says UCLA Health dermatologist Dr. Carolyn Goh.
Since hair is made of protein (keratin), she suggests making sure your diet includes protein, as well as iron and zinc. Vitamins E and D help promote a healthy hair growth cycle, as does vitamin A.
"But you don't want too much vitamin A," she cautions, "because we know that too much actually does cause hair loss."
There are still many unknowns when it comes to exactly how different vitamins and minerals affect our hair, but one recent study shows how what we eat and drink may play a role in hair loss: this 2023 Chinese study found that high consumption of sugar-sweetened beverages is linked to male pattern baldness.
Most styling does more harm than good
Brushing, drying, curling, straightening, dyeing, bleaching — in our attempts to look better, we often do more harm than good. Many of the tools we use to style or colour hair cause damage to your hair by applying force, heat or harmful chemicals.
"I hate to tell people, 'Don't touch your hair,'" says Toronto dermatologist Dr. Renée Beach. "They want to feel good about it. And hair should be groomed. But the more we manipulate it, the more we're actually going to fracture it."
Chemicals traditionally used to straighten curlier textures, for example, "are inherently breaking … bonds and making the hair weaker and more prone to breakage," she says.
Excessive heat is also detrimental. If you're using a straightener, "the sizzling, the steaming, that is hair damage…. There's no way around it."
As for that old adage that recommends brushing your hair 100 strokes a day, you may want to think twice: while it's true that stimulating the scalp can improve circulation, over-brushing can damage the cuticle and may cause split ends.
Stay out of the sun
Many of us follow doctors' advice to use sunscreen, wear a hat and stay in the shade to protect our skin. But did you know that the sun's ultraviolet rays can also harm your hair?
Marcelo de Paula Corrêa is a Brazilian atmospheric scientist researching how climate change impacts human health. He's also an avid cyclist. So he's been conducting a unique experiment, using special sensors and hair samples attached to his helmet.
He found that hair is damaged by solar radiation, high temperatures and pollution.
Do your hair homework
When it comes to treating hair loss, it's the shiny new gadget or the latest home remedy that often attracts the most attention. But if you have serious concerns about your hair (or the lack of it), instead of scrolling through social media, consider consulting a doctor who knows whether claims are based on credible scientific research.
Part of the challenge for doctors who treat hair and scalp conditions is that science has traditionally dismissed it as a cosmetic concern, which means that research is often limited to a specific population (and that population is often white men).
For example, you may have heard that rosemary oil can help with hair growth. "The issue is there's so much nuance in things," says Dr. Beach. "Read between the lines. Rosemary oil was studied in a particular population — men — versus a particular concentration of a medication — two per cent minoxidil — in a particular hair condition. So were you a man? Did you have that same hair condition? And would you use two per cent minoxidil? If the answer is no, no and no, then you might want to think twice about putting the rosemary oil on your scalp."
The main drugs prescribed for androgenetic alopecia (patterned baldness) have been around for decades. "When we think about what's approved for hair loss or hair thinning in North America, not much has changed," says Dr. Beach.
New therapies and drugs offer hope for treating hair loss, but it's important to separate the science from the latest trends you might see on TikTok.
Some newer high-tech therapies involve injecting exosomes ("messenger" particles released from cells) or PRP (protein-rich plasma from a patient's blood). However, they can be extremely expensive, and data about their efficacy is limited. One increasingly popular therapy uses low-level light from lasers (LLLT), often through a cap or comb, to stimulate hair growth. This 2021 analysis of 15 studies on LLLT's safety and effectiveness concludes that it's a viable treatment option but recommends further study.
According to a poll of 2,000 Americans conducted for hairmax.com, we struggle with bad hair days more than a week out of every month. It's no wonder so many of us go to such great lengths trying to fix it.
Just remember that there's no magic cure for most hair issues, and if it sounds too good to be true, it probably is.
