This cream contains prescription-strength estrogen and progesterone. The over the counter creams on Amazon and elsewhere, contain a fraction of the dose and are not effective, that is why they are allowed to sell them without a prescription form a licensed medical professional. Dr. Green is a board-certified OB/GYN. The cream he prescribed for you contains a 50:50 ratio of estradiol and estriol, 5 mg/mL (2.5 mg per day). That is about 10 times the strongest dose he could find on Amazon. It also contains 200mg per mL of micronized progesterone.
We understand how confusing this is. It took us a while to really do the math and understand how they get away with selling these hormone creams on Amazon and other places. The answer lies in the dosages and the specific hormones. In the case where these Amazon creams contain real active hormones, the dose is tiny. In some cases the creams contain hormone precursors that sound impressive but aren't even active in the body.