Fosamax Dosage. The Fosamax dosage that you are prescribed will depend on the condition being treated, whether you want to take a daily or weekly dose, and other factors. The recommended dose for osteoporosis in men and postmenopausal women is either Fosamax 70 mg once weekly or Fosamax 10 mg once daily. Regardless of your Fosamax dosage, you must remain upright for at least 30 minutes after taking it.