Progesterone is produced from cholesterol with pregnenolone as a metabolic intermediate . In the first step in the steroidogenic pathway , cholesterol is converted into pregnenolone, which serves as the precursor to the progestogens progesterone and 17α-hydroxyprogesterone. These progestogens, along with another steroid, 17α-hydroxypregnenolone , are the precursors of all other endogenous steroids, including the androgens, estrogens, glucocorticoids, mineralocorticoids, and neurosteroids. Thus, many tissues producing steroids, including the adrenal glands , testes , and ovaries , produce progestogens.
Tibolone has tissue -selective estrogenic effects, with desirable effects in bone , the brain , and the vagina , and lack of undesirable action in the endometrium and breasts .  Its tissue selectivity is the result of metabolism , enzyme modulation (., of estrogen sulfatase and estrogen sulfotransferase ), and receptor modulation that vary in different target tissues, and differs mechanistically from that of selective estrogen receptor modulators (SERMs) such as tamoxifen , which produce their tissue selectivity via means of modulation of the ER.   As such, to distinguish it from SERMs, tibolone has been described as a "selective tissue estrogenic activity regulator" (STEAR),  and also as a "selective estrogen enzyme modulator" (SEEM). 
The exact dosing instructions for nitric oxide supplement is not known. However, most supplements contain an average dose of grams of L-arginine and L-citrulline. We suggest you follow a process known as tolerance mapping to understand just how much nitric acid is required for your body. The process is simple. All you have to do is start with a small dose in Week 1. During the first week, make sure you note down the benefits and side effects that you are feeling. Once your body has adjusted to the lowest dose possible, you can then increase the dosing until you start feeling beneficial effects. Gradually, your body starts adjusting to the supplement and you will hit your optimal dose. However, the temporary recommendations for the supplement that you can take 2000mg-6000mg per day for optimum effects. Please note that overdosing is possible as dose variations can happen due to physiological differences. In case you notice diarrhea, vomiting, weakness, and nausea, stop the supplement immediately and consult your personal physician. Please note that liquids are absorbed much faster than solids and dosages for liquids will be lower than that of solid preparations.