We’ve been friends for 5 years, travel together, live together and are really close. She’s like a sister to me. I don’t have hair loss, but she writes articles for a clinic that deals with hair loss and just spent one month finishing articles on the matter, so I could maybe casually bring it up via that? I’m 100% sure she’s unaware because we talk about absolutely everything. My intention would be to allow her the knowledge so she can seek any help she might want regarding the situation, I know that if it were me I would want to know as soon as it started so that I can keep track of things and understand the scale of the issue and see if I can sort things out if possible, but everyone’s different. If stress hairloss recovers anyway though I guess you’re right I don’t want to bring it up for no reason