SUBREDDIT: r/loseit
TITLE: [HELP] Side effects of rapid weight loss/poor nutrition. Also, is this Skinny-Fat?
POST: Hi loseit,

First some stats, I'm 5' 9'', 155lbs at the moment. I started at 187, and involuntarily went to 171 after I moved on my own, then I took control and am now at 155.

2 weeks ago I posted this: [Really discouraged after losing 25lbs and discovering that it's probably because of my thyroid.] So I went to the doctor, and from the tests looks like it's not a thyroid problem after all (haven't seen the doctor yet, but my appointment is in 2 weeks)
I was thinking the hair loss and constipation might be related to vitamin deficiencies, are these common side effects? I searched and found only a couple of posts on each, so it doesn't look too common. If they are, I think we should add them to the FAQ or something.

I bought a multivitamin to try and help, is it going to make me gain weight?

Kind of related, I currently have what I think is a skinny-fat look ([PICs - sorry, shitty camera] and I don't know if I should keep the calorie deficit or start with maintenance mode.
TL;DR: 
Is hair loss and constipation a common problem when dieting? Can multivitamin supplements help? Or are they going to interfere with my diet?