Help!! Female reader is ashamed of being skinny

I just got this in my mailbox..Would appreciate if you can help her with suggestions.
"Hi Emeh and fellow BVs. I have a little problem n I need to hear from people how to go about it. I'm a 27yr old lady but I'm underweight. I still weigh below 45kg n it really makes me ashamed of myself. I've tried all I can just to gain an extra weight but I'm still skinny. Is there any supplement I can take just to add up a bit. I don't want to be fat but just ok"