As women age lose collagen . i read collagen supplements can help build immunity, metabolism, hair growth, nails. bone health, post menopause. would it be beneficial ?

Humbug! Supplement are unregulated. Makers do not have to show that what they are selling you is safe nor do they need to prove that what they claim the supplements do is supported by scientific evidence. They can and often do add stuff you do not want to put on your skin including mercury. Using them will benefit the sellers but not you. Weigh the risks and benefits. and discuss with your Dr