Can I take Biosil capsules(collagen,keratin,elastin) immediately after hair transplant?

It is best to ask your surgeon about post operative care as each doctor has their unique regimen.  In general vitamins and supplements are not necessary. 

yes you can use it but I think you would have no benefit for your hair. This kind of market products are produced just for getting money without any treatment purpose .

Taking Biosil capsules after a hair transplant can be taken without difficulty.  Anything you take orally will not impact the hair transplant