Can I give my puppy the vitamins that I buy for myself?

I have this 4 months old puppy who seems to be having a little bit of immune system problems and I want to boost it to help her get rid of her mange and other skin allergies. I read that I could give her neem oil, vitamin C, Omega Fatty Acids, and Zinc to help her immune system. Now I buy for myself vitamin C and Flaxseed and Fish oil for omega fatty acids, and they are pure, all natural vitamins and so forth, so I was wondering if I could just take those and grind them up or empty the capsules into her food or just straight give her the whole pill, or do I have to go all out and spend however much money to buy vitamins that were specifically designed for a dog? Please help, I would like to know, considering that I do not have a lot of money. Thank you.