Why Progesterone Is Just as Important as Estrogen

It’s time to bring progesterone into the conversation about women’s health. That’s according to Canadian endocrinology professor Jerilynn Prior in her paper “Women’s reproductive system as balanced estradiol and progesterone actions—a revolutionary, paradigm-shifting concept in women’s health.” In the paper, Professor Prior makes the case that historically there has been a “cultural over-emphasis on estrogen” while “progesterone tends to be ignored or associated with negative effects.”

How science got it wrong about progesterone

Progesterone has been both ignored and mistakenly blamed for side effects it does not cause. How did that happen?

For starters, progesterone was discovered after estrogen and so missed the opportunity to be part of the perfect hormone dichotomy of “testosterone for men and estrogen for women.”

Next, early preparations of progesterone were poorly absorbed orally so progesterone was of little interest to “the estrogen-discovering scientists, the estrogen-treating clinicians and the estrogen-making pharmaceutical manufacturers, [who] all worked together.” (Modern preparations of oral micronized progesterone can be absorbed orally.)

Finally, progesterone was rapidly replaced by synthetic progestins in both research and treatment even though progestins have different (and sometimes opposite) effects compared to progesterone. The side effects and risks of progestins have since been mistakenly attributed to progesterone. (For example, progestins increase the risk of breast cancer, but progesterone reduces the risk.)

Estrogen and progesterone work together to build long-term health

Women have two main ovarian hormones, not one; and physiologically, estrogen and progesterone work as a team. For example, the pre-ovulatory surge of estrogen (estradiol) is necessary for ovulation and the manufacture of progesterone. Estrogen also works in every tissue to promote progesterone receptors.

In turn, progesterone counterbalances estrogen in all parts of the body including:

  • the uterus, where progesterone thins the lining, while estrogen thickens it;
  • the brain, where progesterone is calming, while estrogen is stimulating;
  • the breasts, where progesterone helps to slow cell division, while estrogen increases cell division.

Progesterone can also promote ovulation by providing important hormonal feedback to the hypothalamus.

👉🏽 Did you know? On a blood test, a good peak luteal phase progesterone level is 80 nmol/L which is 100 times more than an average peak estradiol level of 800 pmol/L (0.8 nmol/L).

Together, estrogen and progesterone promote the long-term health of the brain, bones and cardiovascular system. As Professor Prior says in her paper, “normally ovulatory cycles across a woman’s long reproductive life span are needed to prevent osteoporosis and fracture, heart attacks, and breast and endometrial cancers during women’s older years.” In fact, each and every ovulatory cycle is like a deposit into the bank account of long-term health.

Estrogen and progesterone for long-term health.

Do you make enough progesterone?

A regular ovulatory menstrual cycle is the only way to make progesterone.

Definition: An ovulatory cycle is a menstrual cycle in which your basal body temperatures go up with ovulation and stay up for at least 11 days, indicating a healthy luteal phase.

Progesterone deficiency is caused by:

Progesterone as treatment

As Professor Prior explains in her paper, the first step to reclaim progesterone is “to make visible progesterone’s… presence or absence” in a menstrual cycle. This can be done by tracking ovulation with temperatures and/or an at-home progesterone test. Knowing if and when you ovulate is called body literacy.

If progesterone is absent, ovulation (and progesterone) can be restored by reducing stress, eating enough, and promoting optimal general health. See Roadmap to progesterone.

👉🏽 Tip: According to the American College of Obstetricians and Gynecologists (ACOG), ovulation is an expression of general health or a “monthly report card.”

If ovulation cannot be easily restored, there is also the option to take progesterone as cyclic progesterone therapy, which is a promising treatment for PCOS, irregular cycles, and the heavy bleeding of perimenopause.

For more information about progesterone and PCOS, see my paper The central role of ovulatory disturbances in the etiology of androgenic polycystic ovary syndrome (PCOS)—Evidence for treatment with cyclic progesterone.

For more information about progesterone and perimenopause, see my book Hormone Repair Manual.

43 thoughts on “Why Progesterone Is Just as Important as Estrogen”

  1. @larabriden

    Hi Lara, I’ve recently read your period repair manual. I’ve stage 4 endometriosis with recurring endometriomas. I’ve had 3 surgeries in past 4 years. My gynecologist wanted to give me monthly injections to suppress my hormones (temporary menopause) so to prevent another surgery in the short term. I wasn’t prepared to do this and asked him to prescribe me micronized progesterone instead (utrogestan) as I read about this in your book. I’m currently taking serval supplements; DIM, milk thistle, vitex, NAC, zinc, magnesium & vit b complex, tumeric and fish oils. Would any of these affect the micronized progesterone or visa versa?

  2. Hi Lara,

    I recently bought your book on Period Repair Manual and have been reading it a lot. I am 28 and have stage 4 endometriosis with 3 surgeries in the past 4 years to remove large ovarian cysts which have had to be done through open surgery instead of a laparoscopy due to their size. I’m currently recovering from my latest surgery. I am therefore trying to turn towards a more natural and holistic approach to treating my endometriosis. I am currently taking a supplement called DIM (Diindolylmethane) along with milk thistle to try and balance my estrogen. I haven’t come across this supplement in your book and I’m just wondering if it’s something you know about or advise for estrogen excess/endometriosis?

  3. I was having perimenopause symptoms for over 1 year (poor sleep, migraines, joint pain, severe pms & breast pain). After a work up to eliminate other causes my health provider prescribed 100 mg prometrium nightly. I also take magnesium, and several other supplements you recommend and eat wheat and dairy free! It worked wonders for 10 months then suddenly symptoms returned and I am miserable again.

    Is this typical in early perimenopause (not missing periods yet)? Should my dose be adjusted?

  4. Dear Lara, After reading your last post, I started progesterone cyclic therapy (100mg at night). It is my second cycle, however I have early periods (my period came on the 19th of my cycle, plus spotting). I am also taking spironolactone, and I was before I started the progesterone cycle, but I thought it would help with the irregular periods. Although I am of normal weight, I have PCOs, insulin resistance, struggle with acne, hair loss, and insomnia. Without spironolactone, my cycle is normal, around 26 days. My DHT was very high, so I was advised to take it. What should I do, increase the dose of progesterone? Or should I wait one more cycle before changing the dose?

  5. I recently had a partial hysterectomy and had my uterus and ovaries removed due to endometriosis/endometrioma. I still have my cervix. Can you please let me know if you recommend progesterone and/or testosterone for people in my situation? If so, can you share how you think about what’s the right dose? Meaning, do you have target blood levels or target symptoms you work towards?

    • if your ovaries are removed, you are in surgical menopause, which can require estrogen + progesterone therapy, and yes, maybe also an androgen like low-dose testosterone or DHEA. What does your doctor recommend?

  6. Skipping 1 or two months of periods at a time, 1 period in the last 4 months (in between though so I’m not close to 12 months). Should I take progesterone or estrogen AND progesterone? Hot flashes, night sweats, sometimes heart palpitations and feelings of unwellness and anxiety and terror at night also. Magnesium and taurine and still suffering badly from symptoms some days. 45 years old.

    • I am in similar boat to you Jessica. I am 43 with irregular periods and perimenopausal symptoms for last few yrs. Taking Magnesium + Taurine for heart palps and migraine, which has totally helped (bonus that also seems to have helped with bloating and possibly also anxiety and brain fog…). I’ve not had a period for 3 months (bit longer than usual) AND this coincides with suddenly getting MULTIPLE NIGHTLY wakes from reasonably intense/short hot flashes for last 8 wks. Just saw Dr who prescribed Estradiol patch + Progesterone. Have yet to start – considering taking Progesterone only (100mg) based on what I am learning here/in book, but unsure whether to take cyclically or daily in my situation…?

  7. Hi Lara, the protocol from the AMS for cyclical treatment is to take it for. 12 days. You say 14…what is the reason for this? Also will you still get the benefit of progesterone for treating symptoms when you only take in cyclically and not daily? Thank you

  8. Do you know if high dose ibuprofen effects progesterone and ovulation? I am prescribed 2400 mg of ibuprofen daily for inflammatory arthritis. I use the Marquette NFP method and I did not have a peak on the monitor this cycle. I have yet to have a period and I’m on day 50. I have had 2 negative pregnancy tests. I am 40. Does the ibuprofen prevent natural cycle? I was always regular and predictable before this. thanks.

  9. I have read your book The Period Repair Manual. I have endometriosis, had surgery 18 months ago at 42 the surgeon told me mine is a mild case and now there are cysts on my ovaries agai. Dr. wanted to start me on Visanne. I refused it and requested Prometrium. Unfortunately it is not available in UAE and she prescribed Endometrin vaginal suppository. I have used 3-4 days first month and had a normal period not heavy. This month after 4 doses I havent had my period which has never happened to me except for pregnancy. So my understanding is that Prometrium would not have stopped the period right? And Endometrin is a progestin or Body identical hormone?

    • Endometrin is body-identical progesterone. You mean you took it for 4 days leading up to a period that was due? But the period didn’t come? Could be lots of factors such as a later ovulation this month due to using it last month. Which would not necessarily be a proble.
      Or if it’s very high dose, it could prevent a bleed. What dose it is?

  10. Hi Lara,

    I have your Period Repair Manual book and can’t wait for your new book to come out. In the meantime, I need your advice. My period started being irregular when I was 33. I completely lost my period 9 years ago when I was 41. I don’t have any menopausal symptoms but I lost a lot of hair since my period stopped. My DHEAS is higher than normal for my age. Can I start taking estrogen and progesterone now? If yes, do I need to take them separately (14 days each) or at the same time?

    Thank you,

  11. If a young girl has very low estrogen from her ovaries and has insulin resistance, how does she increase her bodies sensitivity to insulin and increase the estrogen naturally and permanently? The low estrogen is responsible for her lack of ovulation so how does she increase estrogen. You need estrogen to induce ovulation; not vice versa.

  12. “On a blood test, a good peak luteal phase progesterone level is 80 nmol/L

    If my day 21 Progesterone tests all show around the early 40’s nmol/L”(that’s half!), should I be taking Prometrium? I’m 46.

    I personally dont like week 3 in my cycle because I feel irritable, sick and tired (and was really sick throughout both pregnancies – guessing it’s from Progesterone) … then feel much better in the last week before my periods.

  13. Hi Lara. I have started cyclical prometrium 100mg for worsening pmdd symptoms potentially caused by a crash in progesterone in my literal phase ( I had several bloods taken last month)I felt great initially then irritability started coming back. My day 21 bloods showed my progesterone levels through the room 146 apparently only that high in pregnancy and I have to stop.
    Is this normal?
    I feel soo deflated as I thought this was going to work I’ve tried everything

    • How soon (how many hours) after taking the progesterone was the blood test done? It will naturally cause a transient rise in serum levels, but that is usually not a problem.

      • About 13hours.
        The dr at the Australian menopause centre said this was not ok and I probably wouldn’t be able to take it.
        I actually did feel like early pregnancy my breasts were untouchable sore!!

  14. Hi. I started cyclical prometrium 100mg this month for pmdd symptoms they think are caused by a crash in progesterone in my literal phase (I had bloods over last month) anyway, I was feeling soo much better then all the symptoms started coming back I had bloods on day 21 of my cycle to check and progesterone is through the roof, apparently only that high in pregnancy and I have to stop taking it. I feel soo deflated. Is this normal?

  15. Hi ma’am

    Since the beginning of my first period I got severe pain
    Even of my severe menstrual cramps
    My period is regular and I ovulate each month

    Since 2 year I have recurring uti infection

    But unfortunately I’m trying to get pregnant since one year but in vain

    Last month I got my period on 17 November and ovulate on 3rd December
    I do the progesterone and estradiol test on my 23rd day of my period.
    progesterone was 6.19
    Estradiol was 154.00

    Since I started reading your book I have learned a lot on my body and have realized that doctor have tell me a lot of lies

    Hope to hear from you as soon as possible. I really need your help ma’am

    Thanks in advance

  16. Are you supposed to keep doing progesterone therapy forever? I understand that progesterone contracts the LH irregularities, however, once you stop progesterone, it will likely be the same, or am I wrong?

  17. Thank you do much for this article, Lara.
    I am 47 with regular cycles. I still have at least 16 days luteal phase. According to blood test and ovulation test, I am still ovilating with good levels of ptogesterone, which was confirmed by my ob-gyn, but for the past 6 months there’s no temperature rise beyond 36.3-5°C. It used to get to 36.8°C after ovulation. I am confused. Without temperature rise, does my body get benefits of progesterone? Thank you vety much!

    • you’re making significantly less progesteorne than you did when you were younger. As indicated by the low temperatures and as is expected at 47. Just curious, what was your serum progesterone reading?

    • Thank you very much, Lara, for your comment. My progesterone reading was 49.9 nmol/l (day 16 of my cycle, I ovulated on day 9-10), estradiol was 268 pmol/l. On the day 3 of the same month prolactin was 150 mIU/l, FSH 8.3 IU/L, LH 4.9 IU/L, insulin 2.8 mIU/L.

      Do I benefit from the progesterone even without temperature rise, or is it better to supplement with Prometrium?
      Thank you very much!

      • 49 is a good reading for mid-luteal, but as I describe in period repair manual, progesterone fluctuates on a 90-minute cycle, so one spot reading does not tell the story of the luteal phase as a whole. If your temperatures are lower, then you’re making less progesterone overall.

  18. The peer reviewed paper wasn’t as fun to read to my lay eyes as your posts are but go you! Your work is amazing. You’ve helped so many of us regular folk make better decisions about our health.

    I find I’ve managed my health and weight issues by fasting a week before ovulation. I know you’ve said that we need glucose to ovulate but if the body can convert fat to glucagon through glucongenesis, do you know if I’ll still ovulate to get that lovely progesterone you speak so highly about?

    • Great, thanks for the feedback.

      It’s not that we need glucose to ovulate; we need a certain level of insulin. ie. low fasting insulin can switch off ovulation. The best marker of what’s going on is LH in ratio to FSH. Low LH is often a clear marker of undereating or undereating carbs.

  19. I (40 years)suffer from pcod And adenomyosis. Doing lifestyle changes (off dairy off gluten ).. exercise movement. ..supplements … hv read ur book period repair manual and know that I need micronised progesterone but whom to get it prescribed from ? Gynae doesn’t understand it. Self medication not a gud idea. Am from New Delhi INDIA. Pls help.

    • Brand names for oral micronized progesterone include Prometrium, Utrogestan, Endometrin, Crinone, Cyclogest, Endogest, Endometrin, Estima, Geslutin, Gesterol, Gestone, Progesterone, Progestogel, Prolutex, Proluton, Prontogest, Strone, Susten, and others.

  20. Fascinating—although I can’t access the whole article. I believe you’ve said in some of your prior posts that for women who aren’t in peri/menopause, it’s better to try to make more progesterone naturally, but this seems to be saying that taking progesterone may be a better course of action for some women with PCOS (which I have). Has your thinking on this changed? How do you know if you are better off trying to increase progesterone naturally or if you need to take a progesterone supplement?

    • oh, the full article should have been available from that link. You can also access the PDF from CeMCOR’s site Paradigm Shift in Women’s Reproductive Health.

      As for progesterone and PCOS, it IS important to try to establish ovulation and therefore natural progesterone production. That is the ultimate goal of cyclic progesterone therapy but it will also induce some progesterone withdrawal bleeds in the early stages of treatment.

      • I do ovulate every cycle, I just have irregular cycles with delayed ovulation and often don’t have great temperature shifts and/or shorter luteal phases (some cycles are better than others, there is a lot of variation). I’m 36, but this has always been an issue. Would progesterone supplementation be appropriate for someone like me, or do I just keep trying to support my own progesterone with B6, vitamin C, magnesium, etc?

      • I do ovulate every cycle, but I have longer cycles with variations in cycle length (usually 35-50 days), and variations in temperature rise/luteal phase length, so I know that my progesterone levels are not great. I am 36 but this has been the case my whole menstruating life. I am considered about the effect of the low progesterone levels (and less frequent ovulation) on my bone density and endometrial cancer risk, among other things. So that’s what made me wonder if I just keep trying to support progesterone with things like B6 and vitamin C, or if I should pursue a progesterone supplement.

        • short answer, progesterone supplements can be helpful, yes.
          Longer answer, you still want to try to figure out why you’re not ovulating more regularly. Possibilities: PCOS-type situation, undereating and/or over-exercise, low carb, vegetarian or vegan, nutrient deficiency, high prolactin, thyroid, gluten and more.

          The strategy is to correct the underlying issue and then the regularity and robustness of ovulation should improve on its own.

          • I know I have lean PCOS (normal weight but I carry extra weight around my stomach); I am both insulin resistant and have elevated DHEA-S. I have cut out gluten, dairy, and sugar and take a number of the supplements you recommend, and I have seen some improvements, but my ovulation is still easily delayed by stress and I struggle with sleep issues and cortisol. I’m just not sure where to start with a progesterone protocol, even if I could find a sympathetic doctor (I’m in the US), because I do ovulate, but not on the same day every cycle. So not sure how to superimpose the progesterone onto my cycle, and if this would be temporary or indefinite, continuing into perimenopause?

          • Thanks fire replying, Dr Briden. To answer your question, my last FSH/LH was done Sept 2019, and it was FSH 6.2, LH 5.6. I had weaned my baby in July 2019. The year before I had a profile done when I was nursing and hadn’t started cycling yet and had FSH was 5.5 and LH 9.9. I always have normal thyroid, had DHEA-S of 345 while nursing and 255 when not. History of very low Vitamin D. I have moderate jawline acne (better now that I cut out dairy), hirsutism, and my hair is thinning along my hairline. My last 6 cycles have been 39, 28 (v short luteal phase), 44, 29, 49, and 32 days. I have slow temp rise and/or shorter luteal phase in many of my cycles. I was diagnosed with glucose intolerance (after 3 hour test) in my last pregnancy. I eat carbs moderately but not low-carb, do not restrict calories, and have cut out sugar, dairy, and gluten.

            My PCOS is not dramatic enough that my doctors care much about it, and I have 4 kids, so technically no infertility (although I had several early miscarriages which I think were down to low progesterone). At this point I am concerned about hair loss (not sure if progesterone would help), bone density, cancer risk, etc, and I’m wondering if I should be supplementing progesterone to be proactive about my health.

          • Also, I don’t know if this was helpful, but my testosterone results were

            Testosterone 20
            Free Testosterone 1.7
            Bioavailable Testosterone 3.2
            SHBG 50

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