This hormone is primarily made in the ovaries of women and testicles and adrenals of men. It has several important functions for each sex.
For women, one of the important roles of progesterone is in balancing estrogen effects on the uterus, keeping the lining from overgrowing and causing the shedding during the menstrual cycle.
During the first 2 weeks after menses, progesterone is produced in very small amounts. When an egg is released at ovulation (about 2 weeks into the cycle), progesterone production really begins and continues for approximately 2 weeks while estrogen is high, exerting a balancing effect. Near the end of that time, both hormones begin declining, sometimes rapidly (causing more symptoms) and other times more gradually until they are both at very low levels and the next menses ensue.
Progesterone is essential for creating a thickened uterine lining that can receive a fertilized egg, thus creating a viable pregnancy. One of its important jobs is to prevent excess estrogen effects. Any young woman planning to get pregnant should make sure that she has healthy progesterone levels. Inadequate progesterone can result in a miscarriage and it is an important factor in determining fertility.
Progesterone also has a major effect on mood. To control this, it is extremely important during the 2 weeks leading up to a menstrual cycle that the body produces adequate amounts of progesterone.
Low progesterone during this time can lead the way to estrogen dominance, which creates PMS symptoms and emotional imbalance.
The more infrequently a woman ovulates, the less progesterone she is producing. But progesterone plays other important roles in our bodies, too. In both sexes, it is a critical factor in maintaining brain function including good cognition and memory. Progesterone has positive effects on neurons and helps to regulate neurotransmitters, such as dopamine and GABA (associated with learning, memory, and a sense of calmness).
Progesterone is a natural anti-depressant and sleep aide with its major effects on neurotransmitters of several types.
Scientists are currently looking at progesterone replacement to aid in the prevention of memory loss and to limit adverse effects on the brain after brain trauma.
Progesterone has shown beneficial effects when administered immediately after strokes and heart attacks to help reduce global cerebral ischemia. In these events, the lack of oxygen to the brain has negative effects on memory and cognitive function. The use of progesterone in these circumstances has been demonstrated to reduce the narrowing of the brain’s memory center, the hippocampus.
Furthermore, progesterone is required for healthy bone development and preservation, and plays a significant role in the prevention of osteoporosis. It is directly involved with maintaining good bladder function, acting as a natural diuretic to regulate fluid balance.
Progesterone provides healthiness to hair, skin, and nails, and helps prevent hair loss.
It protects against endometrial cancer, prostate cancer, and fibrocystic breast disease. Blood sugar and insulin levels are better regulated in both men and women when progesterone is optimal.
The thyroid function is directly affected by progesterone levels, so it naturally follows that temperature regulation is supported by this hormone.
It is a misconception that a hysterectomy eliminates the need to give progesterone even when estrogen is replaced through hormone therapy. Although this surgery clearly makes the effect of progesterone on the now missing uterus lining irrelevant, it fails to take into consideration all the other functions of progesterone in the body.
During a hysterectomy, the receptors for progesterone on every cell of the body are not removed! They are still there and need progesterone to create the physiologic balance they influence.
In short, progesterone affects nearly every part of our body. It can be taken as capsules orally without negative effects by most people, under the tongue in the form of rapid dissolve tablets, or as suppositories or creams in the vagina or rectum. Because of specific molecular aspects of progesterone and the variation in patients’ skin absorption, topical application may not be the best delivery method for consistency in dosing.
All said, progesterone affects nearly every part of your body, male and female, and is a very important hormone in ensuring our well- being.
Jane Kennedy, CFNP, MN, MPH