After a Mumsnet user took to the online parenting forum to ask if she should opt for a fresh pair after every wear, many were quick to weigh in.
“I wash my pjs every time I wear them,” one commented. “[I’m] confused I don’t wear underwear with them so would feel like I was wearing a pair of pants twice.”
“People sweat in bed, and many will go to bed without washing as they shower in the mornings, so that is enough reason for me to wash pjs after one night,” agreed another.
But others weren’t so keen on increasing their laundry duties.
“I don’t have the time, energy or desire to launder five pairs of pjs every night. That would be… 35 pairs of pjs a week!!!!” one parent penned.
“Some MN-ers washing habits completely leave me shocked,” remarked another. “Won’t someone think of the environment?”
Thankfully, Professor Sally Bloomfield, chair of the International Scientific Forum on Home Hygiene has put the discussion to bed once and for all.
"Pyjamas are against your skin. You shed skin cells at a vast rate all the time,” she explains.
“They are full of microorganisms. We all have skin and gut organisms that are usually not harmful on our skin and in our gut. But if they get into the wrong place they can cause problems.”
“Quite a lot of us carry staphylococcus bacteria, which can cause infections if they get into cuts and bruises. We all carry E Coli bacteria in our bowel. Again, most strains are not harmful. But if they get into the urinary tract they can cause infection, cystitis.”
In short? Unless your PJs are significantly soiled, Bloomfield advises that they are washed at least once a week.
However, if you’ve been ill or tend to be a sweaty sleeper it’s important to up the frequency.
“Washing should get rid of most microbes, but not all if you’ve warn them for two weeks,” she added.”
“The clothes won’t be hygienically cleaned because the microbes will have built up, so they will be transferred to underwear and other clothing that comes into contact with the skin.”
This article originally appeared Women's Health.