Faced with busy mornings, we skipped washing our hair for a day, maybe two. But what happens when we string a shampoo fast out for several days, even weeks, at a time?
Tales abound online of people claiming they stopped hair washing for as many as five years . The scalp, they say, unhindered by shampoo, makes its own oils that eliminate the need for expensive conditioners or time-consuming wash routines.
In reality, just what happens when hair goes unwashed depends on you, said Angela Lamb, M.D., a board-certified dermatologist with Mount Sinai Hospital in New York.
“Certainly people probably could get away without washing their hair as much,” Lamb said. “But it depends on your genes. It depends on your hair texture. It depends on how much you exercise.”
It all comes down to oil glands that exist on nearly every area of our skin. Yes, the scalp's oil glands do naturally coat the hair, Lamb said, but everyone’s scalp does so at different rates. That means not washing can improve one person’s hair while making another’s smell like sour milk.
“Hormones affect it. Medications affect it,” she said. “Some can do four, six, seven, eight, nine weeks without shampooing. But it’s detrimental for others.”
Here’s what could happen if you stop shampooing, depending on your lifestyle and hair type.
You hair could smell nasty or stop growing
Hair traps moisture, Lamb said, meaning that built-up bacteria on unwashed scalps can start to pick up a mildewy or sour smell after several days or a week, especially if exercise is involved.
“If you run five miles a day, you can’t go three months without washing your hair,” said Lamb.
Odors build up easier in thicker hair, too, making it key to really dig and clean the scalp during washings.
Prolonged periods of not washing can cause cause buildup on the scalp, damaging hair and even impeding its ability to grow, Lamb said.
Grime from dirt, oil and hair product can show up within four to six days for people with finer, straighter hair. Those with coarse or curly hair can buy a bit more time, she said, as many as 10 days.
If itchy dandruff or a scaly scalp occurs, it may feel tempting to scratch. But that could further damage your scalp or hair. “That’s never particularly helpful,” Lamb said. “You want to try to treat the underlying problem.”
Many who forgo washing describe experiencing a certain breakthrough after several weeks where their hair seemed to readjust from lack of washing, going from grimy and slimy to thicker or naturally voluminous.
“Certainly there is some truth to that, that if you overdry any skin surface by shampooing or harsh detergents, that it will make more oil to try to compensate,” said Lamb, but she does call for balance.
Non-washing advocates invoke simpler times, when the hair of ancients existed free from chemicals or soap. Those people also dealt with matted hair and lice, she said, conditions less accepted today.
While no scientific studies exist the topic, Lamb said, she has seen that people with thin, fine or less oily hair tend to experience greater success with prolonged non-washing.
“For them, frequent washing and shampooing was probably too damaging for their hair,” she said.
It helps if you don’t sweat much or live in a drier climate, too. Cosmetically speaking, people with curlier hair can get away without washing longer than most before it visibly affects the hair, Lamb noted.
How do you know if not washing is right for you? Try going three to four days without a wash, Lamb said. If the hair just feels a bit greasy or dirty, keep going. You’re probably not harming your hair. If itchy scales or redness start to form, though, reach for the shampoo.
“That’s your body trying to tell you that it needs more frequent washing,” Lamb said.