Body hair should only be used as a last resort because the growth cycle is short (about 6 months) and the thickness is poor. The best approach if you don’t have enough hair is to get Scalp Micropigmentation to augments a well planned hair transplant. I wrote about it here: https://newhair.com/wp-content/uploads/2018/11/Combining_Follicular_Unit_Extraction_and_Scalp.98621.pdf