Can Progesterone Be Too High?

Francesca Lyon, Director of Nutrition at FUTURE WOMAN explores the idea that progesterone may be our most important hormone and breaks down whether having too much progesterone can help or hinder our hormone, physical and mental health. 

I am going to ruffle a few feathers here, but I believe that progesterone is our most important hormone. And yet its sister hormone estrogen gets all the attention! Not just in terms of research (where there’s 3x as much) but also in the availability and approach of hormone replacement therapy. Doctors almost always prescribe body identical estrogen to patients experiencing menopausal symptoms, but rarely body identical progesterone.

Progesterone is a hormone that we need to be talking about MUCH more in the hormone health world, not just for fertility but for mental health, physical health, sleep and mood.  

You may know progesterone for its fertility supporting benefits, or its role in pregnancy. Or maybe you are experiencing the first hand importance of progesterone as your levels are dropping in perimenopause leading to symptoms like shorter cycles, PMS, poor sleep, increased anxiety and irritability. 

First lets dig into what progesterone is and why it is so vital for women’s health:

Progesterone is an endogenous steroid hormone primarily produced by the corpus luteum (a temporary endocrine gland created from the follicle that released the egg) after ovulation, but smaller amounts are also secreted by the adrenal cortex.

We often hear of the importance of progesterone for fertility, and the fact that during pregnancy, the corpus luteum provides progesterone production for the first 10-12 weeks. And yes, progesterone is crucial for preparing the uterine lining for implantation of a fertilised egg and helps maintain a pregnancy until the placenta develops. But beyond pregnancy, progesterone plays an incredibly important role including having calming and soothing effects on the body and brain. Progesterone also acts as a natural antihistamine, reduces inflammation, regulates immune function, supports the thyroid, and is vital for brain, bone, and breast health. It also helps balance sleep and promotes a healthy menstrual cycle. 

So to summarise we NEED progesterone for our vitality and wellness as women, not just for pregnancy but for mental and physical health and we need it in optimal levels too. 

So why is progesterone not spoken about more?

Despite its wide-ranging benefits, progesterone is often not given enough attention compared to estrogen. As I mentioned the widespread assumption that estrogen is the primary female hormone has negatively impacted women’s health in several ways, including a significant disparity in research funding, limited availability of body-identical progesterone HRT options compared to multiple brands, dosages, and forms of estrogen, and the exclusion of progesterone in most hormone testing.

In daily clinical practice I have seen that low progesterone is a common hormonal imbalance seen in women of all ages, linked to various symptoms such as anxiety, poor sleep, heavy periods, spotting, fertility issues, and worsened PMS. Conditions like PCOS, endometriosis, and thyroid issues are also commonly linked to low progesterone.

So progesterone is vital but can you have too much of it?

Like with all of our hormones, we function best and have the most balance in our body and mind when our hormones are in their optimal range, therefore this means not too low and also not too high. 

Although I am always advocating for more progesterone, especially in perimenopause (yes that may mean you need progesterone support as early as 35!) and ALWAYS in conjunction with oestrogen HRT, it is true that yes, progesterone levels can also be too high. 

Essentially elevated progesterone may be a sign that something else is going on, for example it can be associated with ovarian cysts and chronic stress, or, rarely, ovarian cancer or congenital adrenal hyperplasia (CAH).  Of course it is also high in pregnancy and when high levels of progesterone Hormone Replacement Therapy (HRT) are taken.

Symptoms associated with high progesterone levels can include breast tenderness, abdominal cramping, back pain, vaginal bleeding, and dizziness due to low blood pressure. High progesterone can also slow down the digestive system, potentially causing slow transit time, constipation, and bloating. Additionally, some women with high progesterone may experience fatigue and insulin resistance which can lead to symptoms such as weight gain, acne and even head hair loss. 

What about progesterone in PMDD?

Progesterone and PMDD is a very interesting topic, as many women with PMDD have a very sensitive reaction to changing levels of progesterone, in particular to allopregnanolone (a neurosteroid and metabolite of progesterone). Therefore some women find their PMDD symptoms worse when progesterone is increased or they take progesterone HRT, whereas others find great improvements with higher levels of progesterone as this can prevent fluctuations of progesterone across the luteal phase. I have found in clinical practice that each case is different and an individualistic approach needs to be taken before deciding if progesterone needs to increase for that person. 

Progesterone and HRT

At FUTURE WOMAN, we are advocates for body or bio identical progesterone HRT in perimenopause as opposed to synthetic progestins which can worsen symptoms like weight gain and leave estrogen unopposed outside the uterus. But it’s not a silver bullet – like all HRT it needs regular testing and adjustment. In early perimenopause, progesterone without estrogen can provide many benefits and may be all that you need. But in later stages of perimenopause when estrogen levels are dropping, progesterone may worsen symptoms and reduce estrogen’s brain protecting effects.

So how do you test progesterone?

To determine progesterone levels, testing is necessary. While regular, healthy ovulatory cycles usually indicate sufficient progesterone production, factors like stress, PCOS, perimenopause, over-exercise, and under-eating can lead to low levels due to lack of or poor ovulation.

GPs typically test progesterone using blood tests, often around day 21 of a 28-day cycle or 7 days before the expected period. However, progesterone levels fluctuate throughout the day and the luteal phase. Therefore I always advocate for urine testing, like the FUTURE WOMAN Advanced Hormone Test, as it is considered a more accurate method as it reflects the average progesterone levels over 24 hours. It also measures progesterone metabolites, alpha-pregnanediol (a-Pregnanediol) and beta-pregnanediol (b-Pregnanediol) which can provide vital information especially around why you may be struggling with anxiety or poor sleep. 

To summarise, we need more of the spotlight on progesterone, and this is why I am always advocating for women to be testing their levels to ensure they have optimal levels as every woman deserves to feel their best, to feel well and vibrant, as well as feeling calm, clear and level headed.