You want to stay away from progestin. Progestin is a laboratory produced progesterone replacement, and it comes with unpleasant side effects, and some possible health hazards.
The best thing to use is natural progesterone, USP. (Pharmaceutical grade progesterone from plant sources, principally wild yam.) This form of progesterone most closely resembles the progesterone that is produced in a woman's body, and has no side effects or healt hazards. The main thing to keep in mind with this form is to find an amount that works for you, and to not use too much or to little.
You want to look for progesterone cream, and you'll want to apply it to your hips, behind, and stomach. With this method, it is absorbed into your fatty tissue where it is available for the body to use as needed. If you use a form that is taken orally, you lose most of it through the liver.
You can usually find this kind of product in good health food stores. Probably not GNC kinds of health food stores, but most other kinds should have it.