Few people know this – air pollution can cause hair loss. So can sunshine, free radicals and second hand smoking.
That's what US-based hair scientist Jeni Thomas, PhD, and co-founder of hair retention company KeepItAnchored, says leads to a condition known as scalp oxidative stress – accelerating hair loss in men and women.
Air pollution was also implicated in Korean research published just last month, looking at the effect on human hair of dust and fuel particles in reducing the levels of key proteins needed for hair growth and retention.
That research suggested people in cities might be more prone to hair loss and baldness as well as those living close to industrial sites. And though the Korean research said more work needed to be done outside the laboratory to confirm the findings, Thomas says that study corroborates others, including KeepItAnchored's own clinical trial – which also points to harmful UV rays, as in the hole in the ozone layer close to New Zealand, also being a key cause.
The six-month trial, designed to show how their products helped prevent hair loss in the first place by addressing scalp oxidative stress, involved 300 people. Designed by a team of dermatologists and hair scientists, it was a double-blind, placebo-controlled study where the participants all used the KeepIt Anchored blend or the placebo.
After measuring hair retention at 8, 16 and 24 weeks, the trial showed those using the treatment had about 2400 more hairs on their scalp than those using the placebo. The measurement was done by selecting a small area on each head, measuring the existing hair, measuring it over the weekly periods and then extrapolating that figure over the whole head area.
"It showed conclusively that those using the treatment enjoyed lower scalp oxidative stress and improved scalp health," Thomas says. "Reducing scalp oxidative stress means hair can be retained for longer."
She is well aware that companies promising treatments to restore lost hair have not always lived up to those commitments: "If you want something that will grow hair where you've lost some – that's not us. We don't do that. If you want to preserve your current head of hair, that is very much us."
So what is scalp oxidative stress and why is it important?
Thomas says there are a few factors in hair loss – genetics and age among them: "But that's not the full picture. Scalp oxidative stress can be caused by ultraviolet rays (usually from sunshine), air pollution involving metals like copper and lead and free radicals [atoms which scour the body to find like atoms, causing damage to cells, proteins and DNA].
"There is also published research on the connection between smoking and hair loss, even suggesting it can be caused by second hand smoke," says Thomas.
That stress causes the scalp's grip on the hair to loosen, she says, and some of the earliest signs are hair coming out on a hairbrush or unusual levels of hair left in a drain after a shower.
KeepItAnchored products are designed to address scalp health, supporting that grip on existing hair, using anti-oxidants to reduce scalp oxidative stress. They vary from a daily treatment to a shampoo which can be applied as the user sees fit.
Thomas says the beginning of summer is the best time to start treatment to help ensure hair loss is minimised. Studies show most of us lose hair seasonally, with much of it usually occurring around late summer or early autumn.
A 2017 study published in the British Journal of Dermatology examined the correlation between seasons and hair loss occurring most frequently in the summer and autumn. It was, the report said, "consistent with prior studies that used trichograms and other hair samples to find… hair loss occurs maximally in the summer."
"I don't know that anyone has definitively discovered the reasons for people shedding most hair in later summer or early fall," says Thomas, "though some people think it's a simple evolutionary thing – we shed hair because we need less of it in the summer months."
But whatever the reasons for hair loss, Thomas says most people are united on one basic tenet: life is better with hair, than without.
For more information: keepitanchored.com