Weight loss and Flat iron?

My hair went from incredibly thick or incredibly thin in the course of a year. (My ponytail is officially thinner than one pigtail. I used to have an undercut to help with the thickness.)

In that year, I started flat ironing my hair 2-3 times a week and lost 96lbs.

I get tons of protein so I was really surprised how quickly my hair got thin.

I only wash my hair 2-3 times a week but my hair comes out in clumps. I also have to clean my brush weekly.

I have purchased Nioxin shampoos, conditioner and leave in to try for 30 days.

I am not quite ready to commit to prescriptions yet.

Is there anything else OTC I should try? I tried searching the sub and couldn’t find much on people who have lost hair due to weight loss.