I've had that problem. I used to be significantly underweight, quite a few times in my life. My hormone levels are low, so I have to be on birth control to even things out. Now I have no problems gaining weight lol. I've tried to go off a few times, but I just can't.
2c-3a - med-coarse - normal-high porosity - high density

NP/LP: CJ Daily Fix, KMF Whenever / Giovanni TTTT
RO/LI: Aussie Moist, CJ Argan & Olive Oil, Hask Keratin Protein
DC/PROTEIN: KC Stellar Strands / CNPF
STYLER: CJ Curl Queen
COLOR: henna, amla & indigo
: glycerin in high/low dews, polyquat-10 & 11, parabens