Following on from my oestrogen basics blog post (Click here to refresh your memory), I wanted to shift the focus to another of our primary sex hormones, progesterone.

Progesterone is made by the ovaries (and in smaller amounts, the adrenal glands and the placenta during pregnancy). In addition to being, in my opinion, the most influential of our sex hormones, progesterone can reduce inflammation, boost thyroid hormone and metabolism, and help us relax and get a good night’s sleep.

If you remember, the luteal phase of the menstrual cycle occurs after ovulation has occurred. Here’s a reminder.

How does progesterone affect my period health?

The basic breakdown of progesterone and your menstrual cycle looks like this: Progesterone peaks after ovulation and plays a big role in getting the body ready for pregnancy. The levels of progesterone in our bodies can then go two ways.

  1. The egg is fertilized, and progesterone encourages the body to develop blood vessels to nourish the womb and provide nutrients to the developing embryo. Once the placenta is established, it takes over this role – but until then, progesterone from the ovaries supports the pregnancy.


  1. The egg isn’t fertilized, and progesterone levels begin to decline, leading to a thinning of the uterine lining and the eventual shedding of the lining of the uterus, known as menstruation (aka your period).

A lack of progesterone in the blood can mean you haven’t released an egg, and therefore haven’t ovulated.

How does progesterone affect the rest of my body?

Progesterone is sometimes referred to as the “counterbalance” of oestrogen, and can help to regulate our stress responses. Benefits of progesterone include

    • Having a happier metabolism
    • Maintaining balanced levels of thyroid hormones
    • Getting a good night’s sleep
    • Healthier bones
    • A calmer, less reactive nervous system – making it easier to cope with stress and anxiety
    • Hair growth
    • Improved brain health and cognition

It has also been shown to help us build stronger muscles too!

Symptoms of not enough progesterone

Having lower amounts of progesterone can present as PMS, bleeding before your period or spotting, heavy or long periods, acne, hair loss and fibroids.

Low progesterone levels have been associated with polycystic ovarian syndrome (PCOS) and can occur if the luteal phase of your menstrual cycle is shortened or non-existent (i.e. you didn’t ovulate).

How do I know if I have enough progesterone?

Testing progesterone is done primarily with a blood test via a referral from your naturopath or doctor. It’s important to note that if hormone testing isn’t done at the right time in your cycle, it’s a useless test and a waste of money.

The ideal time to test your progesterone levels is in the middle of your luteal phase. For some women, this is known as day 21, however – not everyone ovulates on day 14, so choosing to have your bloods taken on this day is not the most accurate way to get your results.


The definition of where the middle of YOUR luteal phase is at, is approx., 7 days after ovulation, and seven days before your next period.

A good naturopath will not interpret your progesterone results until your period comes. They should then ask, “Was this blood test done within the 14 days before you started your period?” – if the answer is no, your test is not accurate and should be considered wrong. 

Assuming your test was done on the right day, an assessment of your levels can take place.   Progesterone levels fluctuate during the day, every 90 minutes in fact. A low-normal reading of progesterone can suggest your result was taken during on of the slumps – this is not a concern.  

Generalizing, your progesterone levels post ovulation should be at least 9.5nmol/L (aka 3ng/mL). From an optimal health perspective, a good level of progesterone sits more around the 30nmol/L (10ng/mL) mark. The body naturally experiences an increase in progesterone during pregnancy, so higher levels are rarely a cause for concern*  

This is all well and good, but how are you meant to know which day to test? It can be quite confusing if you don’t have a regular menstrual cycle.


Alternative to laboratory testing

Charting your temperature when you wake up is a good (and evidence backed) way to see where your progesterone levels are at. If you see a consistent rise in temperature (and you’re not unwell) AND your luteal phase of your menstrual cycle is at least 11 days – it’s a good indication that you’ve made enough of this sex hormone.

Tracking your temperature at the same time each day is important. Using an oral thermometer to 2.0 decimal places and adding these results to an app such as Flo can be useful, as is using a device like the Daysy fertility monitor. 


NOTE: There’s NO progesterone in birth control, despite what you may have been told.


The form of “progesterone” in the pill is a synthetic form known as a progestin.

This synthetic hormone does not give you the benefits you get with your natural hormones. It does not support healthy periods and it does not help your metabolism, nervous system or your bones/muscles.  


The health of your hormones is a long journey – it takes 100 days for our follicles to develop and many factors can affect your hormonal wellbeing.

Your progesterone levels can be affected by inflammation, irregular blood sugar levels, thyroid disease, a lack of magnesium, iodine, zinc, B vitamins, vitamin D, selenium and more. I’ll speak more on this in another blog.



Progesterone is a crucial sex hormone for your health. It plays a huge role in your menstrual cycle and period health – but also boasts massive benefits for your overall wellbeing.

A boosted metabolism, healthier thyroid, greater sleep and relaxation are just the tip of the iceberg when it comes to progesterone’s positive effects on the body.

Testing your blood levels of this hormone must be done on the correct day to avoid false results, and if you’re on hormonal birth control, you won’t have optimal progesterone levels in your body.

Are you concerned about heavy or long periods of bleeding?

Have you considered your progesterone levels might be part of the problem?

There are many reasons why your hormone levels might not be where you’d like them to be, and my intro to progesterone above explains only the basics.

If you are worried about your hormones and your menstrual cycle,

I have evidence informed protocols and herbal medicines indicated specifically for you to help get your periods and sexual health back under your control.

Book an initial consult to get to the root cause of your hormonal concerns so you can start feeling healthier and more like your sensual self again.

*consistently elevated levels of progesterone above what is considered “normal” may warrant further investigation upon the discretion of your health practitioner

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