What are progestins and progestogens?
Progesterone is the female hormone that in women prepares the endometrium (lining of the uterus) for a potential pregnancy. Progestogens have the same biological activity as naturally occurring progesterone but the chemical structure has been slightly altered to improve stability and absorption. Progestins are synthetic progestogens that have a different chemical structure to progesterone but similar biological effects.
Progestins and progestogens are used medically for contraception, hormone replacement therapy in menopausal women and to treat certain conditions like endometriosis.
Use of progestins and progestogens for transgender hormone therapy
Although the clinical opinion is mixed on their effectiveness of use, progestins and progestogens can be used as part of the feminization regime for male to female transgender hormone therapy1. The rational for this is that adding progesterone in some form more closely simulates the female hormone cycle. However, there are also some side effects including, weight gain, oedema, and mood swings. There is also an increased risk of developing breast cancer2.
Progesterone suppresses testosterone production and is also thought to support breast development in transgender hormone therapy, which is one of the roles of progesterone in females. Although oestrogen is primarily responsible for breast development in females, progesterone is involved in regulation the growth and differentiation of breast tissue. Also during pregnancy, progesterone contributes to increasing the size of breasts and the nipples in preparation for lactation.
Progestins, which are synthetic progestogens, available are:
Medroxyprogesterone and hydroxyprogesterone are both administered by injection and are more potent and longer-acting than natural progesterone. Medroxyprogesterone is also available for oral administration as is dydrogesterone. Progestins are more active when taken orally than natural progesterone and do not have other hormonal effects.
Micronized progesterone, in which natural progesterone is reduced to tiny particles for better absorption, is available as a gel and as capsules.
Progesterone is also available for injection in an oil base for stability.
- Wierckx K, Gooren L, T'Sjoen G. Clinical
review: Breast development in trans women receiving cross-sex
hormones. J Sex Med 2014 May;11(5):1240-7
- Axlund SD, Sartorius CA. Progesterone regulation of stem and progenitor
cells in normal and malignant breast. Mol Cell Endocrinol
2012 Jun 24;357(1-2):71-9.