Progesterone vs Progestins

In my 40s I started taking progesterone to manage my period symptoms. I didn’t understand anything about progesterone, or progesterone vs progestins. I just did what my functional medicine practitioner told me to do.

Recently I have learned a lot more about progesterone. I have also learned that the world of progestogens (more on this below) is very confusing.

The Role of Progesterone

Progesterone is a hormone produced by the body that plays an important role in the female reproductive system. It helps to regulate the menstrual cycle, prepare the uterus for pregnancy, and maintain a pregnancy.

Progesterone levels normally rise after ovulation and keep increasing throughout a pregnancy, helping to support the developing fetus. During the menopause transition, progesterone levels decline and become irregular due to anovulation, leading to a decrease of fertility and other symptoms. The symptoms are mostly caused by the unbalanced ratio between estrogen and progesterone.


Progesterone to protect uterusBoth prescribed progesterone and progestins are classified as progestogens. To be classified as a progestogen, the drug must bind to and activate progesterone receptors in the lining of the uterus to enable implantation of a fertilized egg and support early pregnancy.

Protect The Uterus

When it comes to menopausal hormone therapy, progestogens are used to protect the endometrium. The endometrium is the inner epithelial layer, along with the mucous membrane lining the uterus, which thickens during the menstrual cycle in preparation for the possible implantation of an embryo.

Without a progestogen, systemic estrogen therapy can cause abnormal cells or cancer to grow in the endometrium. Meaning, if you have a uterus and take systemic estrogen you need to take a progestogen so that the lining of the uterus doesn’t become cancerous or present with abnormal endometrial cells.

Side note: Systemic estrogen medication contains a higher dose of estrogen that is absorbed throughout the body compared to local estrogen treatment. There are different methods of delivery for systemic estrogen such a skin patch, gel, cream, spray (not available in Canada), ring, or pill. Local estrogen is applied directly to the vagina and vulva at lower doses than systemic estrogen. Typically, local estrogen does not require a progestogen to protect the endometrium since a lower does is used and known to not increase estrogen levels beyond postmenopause levels. As always, seek advice from a qualified medical practitioner.

Heavy Menstrual Bleeding

Progestogens can also be used to help control heavy menstrual bleeding, which can be part of your normal cycle or can be one of many period changes that can happen in perimenopause. Progestins are more potent than ‘natural’ progesterone, and better for controlling heavy bleeding.

Progesterone vs Progestins

Progestins are said to be ‘synthetic’ and are produced in a lab by manipulating other chemicals to link to progesterone receptors and act like the progesterone in the body. The molecular structure of progestins differs from the molecular structure of prescribed or ‘natural’ progesterone. Prescribed progesterone has the same molecular structure as the progesterone produced by your body. Prescribed progesterone is therefore sometimes referred to as ‘bioidentical’.

The progestogen used in combination birth control pills and mini pills are progestins. Mini pills are progestin-only contraception. Whereas combination birth control pills contain estrogen and a progestin.

Prescribed progesterone and progestins are different. And there are many different types of progestins. The team at Women Living Better have done a great job of outlining those differences.

progesterone vs progestin

Prescribed Oral Progesterone (Micronized Progesterone)

Prescribed progesterone is a hormone produced in a lab from plants and has a molecular structure similar to the progesterone that is produced by our bodies. Sometimes referred to as ‘bioidentical’ or ‘natural’ progesterone, these terms can be misleading as it is a drug that is produced in a lab.

To date there has not been a randomized controlled trial to evaluate the safety of prescribed progesterone vs progestins. There have been questions raised, but no conclusive studies, on whether progestins may increase breast cancer risk vs. prescribed oral progesterone.

Progesterone for Premenstrual Syndrome

In my 40s, symptoms of premenstrual syndrome started to reappear. They had been managed by taking birth control pills for years. After having babies, those symptoms seemed to have resolved. Then in my early 40s I started experiencing cystic acne, mood swings, irritability, crying spells, outrageous food cravings, fatigue, constipation, and trouble sleeping.

And my period returned to a shortened cycle of about 15 days, which is what prompted me to start hormonal birth control in my early teens.


Compounded Progesterone

At the time I was under the care of a functional medicine practitioner. They prescribed compounded progesterone on a cyclical basis to help alleviate my symptoms.

I took the compounded progesterone starting on day 12 of my cycle, and if I made it to day 25, I stopped. Otherwise, I would stop when I started to bleed. I would then resume taking the progesterone on day 12 of my next period. Note: day 1 of your cycle is the first day you start to bleed.

See the sub-heading ‘Pharmaceutical vs Compounded’ below for more information.

Progesterone for PMDD

I had good success managing bothersome symptoms of premenstrual syndrome (PMS) with cyclical dosing of compounded progesterone. Daily progesterone, in a pharmaceutical formulation, has recently become ‘the’ tool in my perimenopause toolkit to manage debilitating symptoms that may indicate premenstrual dysphoric disorder (PMDD). Note: PMDD has a specific criteria for diagnosis and is currently recognized as a psychiatric disorder.

Turns out what I thought was PMS might actually be PMDD.

PMS and PMDD Can Get Worse

Compounded progesterone worked well for the return of my PMS symptoms in my 40s, but these got progressively more severe. Perimenopause can make PMS and PMDD worse. In my case, the symptoms came back with a vengeance. A rather scary incident that you can read about here, prompted me to try birth control pills again. That didn’t go well, despite having taken oral contraceptives for years with no issue.

It turned out that a nightly dose of pharmaceutical progesterone was the answer. And for now, it seems to be working well. It is important to note that this is my personal story and experience. It does not necessarily contain scientifically recognized treatments for PMDD and PMS where the goal is to create anovulation and stop the fluctuation in allopregnanolone.

An Important Hormone?

The symptoms that prescribed progesterone has helped me manage are numerous. Many of them very significant. Early on it was cystic acne, a short menstrual cycle, significant cramping, mood swings, and sleep disturbances. My symptoms were well managed with cyclical progesterone that was compounded in a compounding pharmacy.

More recently, pharmaceutical progesterone taken daily has helped with significant challenges like night waking, outrageous premenstrual abdominal pain, and mental health symptoms, including bouts of depression that were frankly, quite scary.

micronized progesterone vs progestin

Micronized Progesterone

Micronized progesterone is listed in the NAMS 2022 Hormone Therapy Position Statement as a treatment option for hot flashes and night sweats, as well as sleep disturbances. Outside of this mention by NAMS in its 2022 position paper and the information provided by the Centre for Menstrual Cycle and Ovulation Research (CeMCOR), progestogens only seem to be mentioned as an option for heavy bleeding and as the complimentary hormone in hormone replacement therapy. Needed to protect the uterus from the cancer-causing potential of estrogen on the endometrium, but otherwise unnecessary seems to be the implication.

Prescribed progesterone is also called micronized progesterone. This term refers to how progesterone is made. The progesterone taken from plants has to be made into smaller bits, or micronized, in order to make it active in the body. Note: only the oral form of progesterone is approved by Health Canada.

Before this technique was discovered in 1980, prescribed progesterone didn’t work as a pill because the stomach and intestines made it inactive in the body. Prior to this discovery, which became commercially available in the mid-1990s, progestins were developed and used to act as progesterone.

Pharmaceutical vs Compounded

When I started taking prescribed progesterone, I had understood that it was only available in a compounded product. However, you can get prescribed progesterone in a pharmaceutical product under the brand name, Prometrium. There are also generic brands available.

The active ingredient in the pharmaceutical and compounded products are the same, but the fillers are different.

As with any medication, have the risks and benefits explained to you by a qualified practitioner.

As per all of the scientific menopause associations regarding compounded products:

“The only circumstance where prescribers might consider using hormone therapy compounds is if women cannot tolerate a government-approved preparation, for reasons such as allergies to ingredients.”

“The bioidentical hormone therapy compound has safety concerns such a minimal government regulation and oversight, over- or under-dosing, presence of impurities or lack of sterility, lack of scientific efficacy and safety date, and lack of labels or inserts describing risks.”

Prescribed Progesterone or Progestins?

Would a progestin help me manage my symptoms in the same way progesterone has? I don’t know. There doesn’t seem to be much information available comparing progestins and prescribed progesterone.

What I do know is that I can’t imagine my life right now without prescribed progesterone. I wonder how many others might benefit if the uses, benefits, and risks of both prescribed progesterone and progestins were further studied and better understood.


This post contains information about a personal experience and does not necessarily reflect scientifically recognized treatments. Everyone’s perimenopausal experience will be unique. Indication of treatment and treatments offered can be different. Health concerns and treatment options should always be discussed with a qualified health provider in the context of your unique circumstances.