History of heart disease, peripheral vascular disease, COPD, liver diseases, abnormal vaginal bleeding, suspected or known breast malignancy, or any other medical condition which physician investigator deems inappropriate for subject participation. Use of regular psychotropic medication (antidepressants, antipsychotics, or anxiolytics) and recent psychiatric history. Amenorrhea. Current use of oral or other types of hormonal contraceptives. Abuse of alcohol or any other recreational or prescription drug. Regular use of any other tobacco products, including smokeless tobacco and nicotine products. Known allergy to progesterone or peanuts.