Quote from: Shantel on March 15, 2014, 11:12:35 AM
I'm always leery of side effects and mine are kind of scary because I had DVT once in my left leg and though my boobs get fuller and feel heavier when I use Progesterone (it's a topical oil based application) I get a weird feeling in that same leg for a day and feel a bit light headed, so I just use it only two or three times a month. The problem is that the endo doesn't really know squat about the side effects, they all know everything about hormone levels and what to prescribe but side effects in MtF patients are a mystery.
There have been plenty of studies (of which I have the full articles) on the use of micronized progesterone either orally or non-orally with review of side-effects. Transsexual women have also been taking it for more than a decade. Here is an early review, one of the first, I believe. This should help alleviate your concern.
Contraception. 1987 Oct;36(4):373-402.
Oral micronized progesterone. Bioavailability pharmacokinetics, pharmacological and therapeutic implications--a review."No side effects have been reported as far as lipids profile, coagulation factors and blood pressure are concerned. Therefore oral micronized progesterone appears suitable for hormonal replacement therapy in various areas, essentially postmenopause therapy, premenstrual syndrome, correction of irregular cycles and pregnancy maintenance."
And a few more...
Gynecol Endocrinol. 1993 Jun;7(2):111-4.
Liver metabolism during treatment with estradiol and natural progesterone.
"Levels of lipoprotein A and liver enzymes did not change. It is concluded that micronized natural progesterone is an attractive means of progesterone supplementation in postmenopausal hormone replacement therapy without any liver-related side-effects."
Gynecol Endocrinol. 1996 Feb;10(1):41-7.
Clinical evaluation of near-continuous oral micronized progesterone therapy in estrogenized postmenopausal women."No significant changes were observed in blood glucose or liver enzymes."
Furthermore, it is prescribed to pregnant women to avoid miscarriage and is similar to the hormone produced in the human body with no increase in DVT associated with it, despite very high levels during pregnancy, reaching up to 400 ng/ml.
Also, this study
The toxicity of progesterone.
Rudel HW; Kincl FA
Tausk, M., ed. Pharmacology of the endocrine system and related drugs: progesterone, progestational drugs and antifertility agents. Vol. 1. New York, Pergamon Press, 1971. (International Encyclopedia of Pharmacology and Therapeutics Section 48) p. 405-409
"The toxicity of progesterone was studied in rats treated for 26 weeks."
"Mortality did not differ appreciably among the groups. Female animals treated subcutaneously had markedly higher body weights after treatment than the other animals. Liver weights were higher in subcutaneously treated females. Atrophy of the gonads was observed in males and females treated parenterally with high doses. Weight changes in the heart, spleen, and kidney were not significant. There were no changes in microscopically examined organs or in hematologic values. Except for the increased body and liver weights of subcutaneously treated females, progesterone did not effect any significant anatomical changes."
This was at doses (given non-orally, hence more potent, in several times) up to approx. 40 times the doses typically prescribed to us orally. The concentrations of progesterone in the blood must have been insanely high!
The only concern I came across was the possibility (although no increased incidence was found) of an increase in risk of cholestasis (obstructed bile flow from liver to duodenum) with high doses of oral progesterone prescribed during the third term of pregnancy when progesterone levels are already naturally quite high in the body.
Also, keep in mind that you are taking progesterone non-orally so there is even less a chance as much less travels through liver.
Lastly, in my review of pharmacokinetics of topically applied progesterone to the skin, I have found it is poorly absorbed in the blood and that there is barely any change in serum levels of progesterone.
From this study (I have the full study)
Menopause. 2013 Nov;20(11):1169-75.
Percutaneous progesterone delivery via cream or gel application in postmenopausal women: a randomized cross-over study of progesterone levels in serum, whole blood, saliva, and capillary blood.The serum levels of progesterone were, on average, with cream and gel (doses comparable to oral),
0.5 ng/ml (Cmax of 0.6 ng/ml) and 0.35 ng/ml (Cmax of 0.4 ng/ml), respectively, during a 24 hour period.
On comparable dose with oral progesterone, in another study, Cmax was found to be 17.3 ng/ml and average levels to be 4.33 ng/ml for the first 10 hours.
As you can see, topically applied progesterone is poorly transferred to the blood.