Hi @ravisante. Thank you for your question!

Hair loss can be quite difficult to deal with but rest assured that post partum hair loss is quite a common condition and usually self resolving within 6 - 12 months even without any form of treatment.

I would say that you should consult your OBGYN and not just start on any over the counter vitamins as many of these products contain way more Vitamins compared to what is normally required. 

For example, lactating women would only require about 35 micrograms of biotin/day. Biotin is secreted in breast milk but has a wide range of concentrations and so far there has not been much documented evidence of toxicity to the infant. 

Vitamin C/B supplements should be fine for consumption if you are unable to obtain enough from your diet. If you eat a balanced diet you should have enough of these vitamins without supplementation. Nonetheless, if you chose to take additional tabs of these vitamins, if has not been proven to cause any issues to the infant. 

I would recommend more of topical treatments such as volumizing shampoo and typically hair care products that contain biotin or silica. 

Hope this helps!