Your body’s most interesting hormone
This rather long “paper” is a condensation of much information, regarding the activities and functions of Progesterone in humans. It is intended to provide “lay” persons with the basic information they need to understand the hormone, cooperate with a functional medicine practitioner and make confident decisions about their own healthcare.
If you need more information, check the other titles in this SUBSTACK, or see “you and your hormones”, an excellent site with an amazingly detailed, in-depth, all–encompassing review of the human hormones. The site is great for a scientific “take” on the subject: it’s too complicated for the casual reader, but it’s useful if you need information.
PROGESTERONE: its name and where it comes from
The hormonal action of Progesterone was discovered in 1929, following the discovery of Oestrogen in 1923. It was named thus: “PRO”, meaning for, or supportive of, “GEST”, short for “gestation”, meaning “pregnancy”and “ERONE”, a short form for “hormone”.
In the human body, Progesterone is produced from Pregnenolone, which is made from Cholesterol: the sequence is as follows.
NORMAL PROGESTERONE LEVELS
In men, and in women during the first 7 to 10 days of the menstrual cycle, the progesterone level is low (< 6 ng/ml) *. In women of childbearing age, progesterone production begins to rise at day 14 of the menstrual cycle and after ovulation it rises rapidly to 30–50 ng/mL. If no pregnancy ensues, it falls as rapidly as it rose, by the end of the cycle.
PROGESTERONE IN THE MENSTRUAL CYCLE AND IN PREGNANCY
A relatively small amount of Progesterone is made in the adrenals.
The ovary makes a lot of progesterone, starting on the 13th-14th day of the menstrual cycle, to prepare the lining of the uterus (the endometrium) for implantation of a fertilised egg. The progesterone level peaks on the 21st day and if no egg has been implanted in the uterus by then, the egg cyst shrinks and the blood progesterone level falls to baseline by the 28th day. Without Progesterone, the endometrium can’t keep going and menstruation begins.
If a pregnancy starts, a hormone called human chorionic gonadotropin (“HCG”) is released by the fertilised egg. HCG converts the egg sac in the ovary into a “corpus luteum”, which produces enough progesterone to maintain the pregnancy until the placenta begins to produce its own supply, at 8–12 weeks. The placenta keeps producing large amounts of progesterone (enough to keep the blood level up to 100–200 ng/ml) until a day or two before the baby is born. ** Then the blood progesterone level falls to its baseline level *** and stays down while the mother is breastfeeding.
* It has been suggested that women have better memories than men do because they make more progesterone. I agree; my memory improved when I started taking it.
** The sudden drop in Progesterone availability is the trigger for “parturition” (birth).
*** If the progesterone goes low enough to cause Allopregnanolone deficiency, serious postpartum depression may ensue, needing treatment.
Progesterone is Indispensable in Human Body Systems
So: progesterone is the pregnancy hormone, but it’s much, much more than that. Progesterone is in many ways the body’s most interesting hormone: certainly, it is the second-most-surprising hormone (the most surprising is vitamin D, a hormone made by the skin).
A quick list of progesterone’s activities
Progesterone is converted into Allopregnanolone, the “king of the brain hormones” and “mineralocorticoids”, which control salt output by the kidneys.
It normalizes the menstrual cycle and is necessary for pregnancy.
It puts us to sleep, via Allopregnanolone production.
It improves memory, also by increasing Allopregnanolone.
It supports kidney function and controls mineral levels via the mineralocorticoids.
It acts to prevent breast cancer.
A high progesterone/oestrogen ratio prevents oestrogenic weight gain on the hips, the breasts and the “tummy”.
A low progesterone/estrogen ratio, referred to as “estrogen dominance” is the reason for the classic “Heavy-breasted, Saddlebag-hipped” female figure seen in some young women.
Progesterone and the brain
In the brain, in a process driven and supported by PEA (Palmitoyl Ethanol Amide), Progesterone generates Allopregnanolone. Allopregnanolone * does brain maintenance, promotes normal sleep patterns, repairs demyelinated nerves, helps to control pain, enhances self-image, elevates mood and improves cognition and memory.
Allopregnanolone is anti-anxiety, prosocial and antidepressant **. It cancels the effects of stress (including stress-related intracellular hypothyroidism) and thus prevents high blood pressure.
* Allopregnanolone deficiency causes depression.
** See “Allopregnanolone” in Wikipedia.
Caveat:
1) The synthetic Allopregnanolone, Zulresso, is very expensive. Progesterone is not and PEA is available over-the-counter in health food stores. If you find it is difficult to get a prescription for progesterone, you can take pregnenolone with PEA at bedtime, and depend on conversion of Pregnenolone – to Progesterone – to Allopregnanolone: that works quite well.
2) A new, oral form of Zulresso, “Zuranolone”, has been approved (2023), but the best supplement for Allopregnanolone is bioidentical progesterone cream, prescribed along with PEA (Palmitoylethanolamine), which is available in health food stores.
Subscribe to continue reading
Subscribe to get access to the rest of this post and other subscriber-only content.