I started Biote testosterone pellets in May 2018 hair started falling out 3 months later, what is the best option for regrowth?

This needs an in-person evaluation. I suggest seeing a hair loss expert now to evaluate and go over your condition and provide you information about your best treatment options. There are great non-invasive options like prp/progesterone and/or hair transplantation. See an expert. Best, Dr. Emer

We do see a small percentage of women who experience hair loss after starting BioTE testosterone pellet therapy.  Often, they have male or female pattern baldness in the family and it is triggered by the testosterone metabolizing into DHT. We usually lower the testosterone dose, and add a DHT blocker such as saw palmetto or even low dose finasteride. We also make sure the person has enough micronutrients in their system for the body to keep up hair growth. A scalp biopsy is very helpful to determine if it is indeed hormonal hair loss or not, we do this and it is very simple and low risk and not painful. 

In a situation like this one needs to know the whole story and more importantly see the scalp up close. Three top possible causes include: 1) a drug induced telogen effluvium 2) a drug induced precipitation or worsening of androgenetic alopecia and 3) a completely different cause for which the testosterone is just a red herring. Be sure to see a dermatologist.