Hi Pepperminty,
I'm not sure if you mean bioidentical progesterone or progestins but they each have a different effect on SHBG.
According to this study progesterone raises SHBG
https://www.ncbi.nlm.nih.gov/pubmed/6538615Levonorgestrel, a progestin used in Mirena, lowers SHBG
https://www.ncbi.nlm.nih.gov/pubmed/6778889...but taken together with ethinylestradiol, like in BCP's , it has little or no effect on SHBG as ethinylestradiol raises SHBG significantly
And according to this research on Tibolone progestens downregulate estrogen- forming enzymes and also induce estrogen- inactivating enzymes.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1924982/. (Page 14)
I'm not sure what they mean by progestogens but I assume both progesterone and progestins?
ZRT lab also mentioned that excessive progesterone can downregulate estrogen receptors
https://www.zrtlab.com/blog/archive/progesterone-estradiol-pg-e2-ratioI just found this information recently and I'm still trying to process it myself but find it very enlightening to say the least.
If progesterone / progestins really downregulate estrogen than that would explain a lot!
I hope this information will give you some inside and maybe others too.
I'm not a native English speaker, I'm from the Netherlands. So my apologies in advance for any mistakes in my language I made.
Alicess