For internal use, zinc sulfate is just fine. The stomach is far more acidic than a dilute zinc sulfate solution. Shampoos like Neutrogena T-Gel or Nizoral are recommended. Although the pattern of hair loss in women is different from that in men, they, too, suffer from androgenic alopecia. The hormone, dihydrotestosterone, causes hair loss in both men and women.
Women can use minoxidil.
However, Upjohn is currently re-examining that recommendation. Use it on all balding and thinning areas. It comes in a plastic bottle with a spray applicator. Most of it settles on the scalp and spreads by itself. Use 4 or 5 sprays and apply it up to three times daily.