This is generally a B group vitamin which should be prescribed by the doctor as dose will be weight and age dependant.

Which vitamin deficiency?

Babies in the first year tend to have scanty hair and also loose hair. This will grow in the second year. Shaving the head does not promote hair growth as it is a very external action and does not affect the roots at all. You must also show the pediatrician to rule out a vitamin deficiency which can easily be supplemented.

Its quiet common shave him bold once and oiling as others suggested will help

hair loss is pretty common in babies. the hair that they are born with are temporary, after some time baby will grow a new set and texture of hair as per his genes. apart from this reason, u can also chk with a doctor to rule out any deficiency. whn i chked doctor said its normal and keep oiling the hair. thats all.