This theory has girlfriends complaining about how they feel after a visit to their boyfriend's place.

They claim that their hair, skin and hygiene are negatively affected by the 'boyfriend air'.

TikToker, Taylor Donoghue, posted a video that has garnered over 2.8 million views and 281,000 likes.

"I am so happy people are now talking about boyfriend air because I actually thought I was going crazy," she said.

"I spent a lot of time this past summer at my boyfriend's apartment in New York, and I remember taking a shower and waking up the next morning and being like 'I feel so dirty'."

"My hair was getting greasy like crazy; my skin was looking different. My makeup wasn't staying on right. I was like, 'what is going on?'"

"I know [boyfriend air] is a thing because it was only in his apartment I would feel this way. When he'd come to me, it was fine."

TikTokers attribute the 'air' to the cleanliness, or lack thereof, of boyfriends' living spaces.

Licensed aesthetician and Director of Marketing for Ever Skincare, Heather Wilson, told NY Post that even the slightest change in lifestyle or hygiene regime can cause changes in one's health and appearance.

"It's easy to get out of our routines or slack on healthy habits when we are not sleeping or spending time in our own homes," she stated.

"Even an occasional change in routine - like not washing your face once or twice a week or eating out more often can impact the health of our skin."

"And make sure he's washing his sheet," Wilson added.

@taylordonoghuee I was truly shook to see other ppl also related to this😭💀 #boyfriendair ♬ original sound - Taylordonoghuee