is this worth $50 or should i stick to the ordinary hair serum?

In my opinion, this serum is worth the cost. It smells great, it does not leave an oily residue on the hair, and most importantly, it contains peptides. Of course this is not to say that this is the only serum that will work; if you are concerned about the cost, and you find a lower priced serum that also contains peptides, go for it. Peptides are where the money’s at.