Your Hormones in Harmony | Part 6

Progesterone: The Elder Sister

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Dr. Aaron Hartman

March 5, 2024


When I began studying medicine in 1996, I was told that after a woman had a hysterectomy or went through menopause she no longer needed progesterone. It was thought that estrogen was the only important sex hormone for women. We now know that to be antiquated thinking; progesterone is a key hormone with many functions in women’s health. Unfortunately, that outdated thinking persists, and progesterone is still commonly overlooked.

Why is Progesterone So Important?

Let’s begin with the benefits of progesterone in a healthy female. Progesterone has many functions:

  • Promotes healthy sleep
  • Lowers cortisol
  • Supports bone strength
  • Prevents anxiety
  • Supports mood stability
  • Helps with bladder function
  • Lowers risk of breast cancer
  • Fights inflammation
  • Thickens hair on the scalp
  • Improves metabolic rate for healthy weight
  • Improves immune function

Progesterone’s role in lowering cortisol is critical for quality sleep and stress management. Bone health, mood support, immune function, hair health and even metabolism rely on healthy levels of progesterone.

Estrone (E1) is converted to a safer, inactive form of E1 sulfur by progesterone. This is important because other metabolites (breakdown products) of estrone can be cancer-causing and inflammatory. Progesterone helps prevent the creation of these metabolites.

Progesterone Decline

When women are in their early 30s, progesterone levels begin to decline. In their 40s, progesterone drops further and then falls off sharply after menopause.

Progesterone decline actually begins before estrogen, so many hormonal side effects and symptoms women feel are actually due to progesterone insufficiency (and later deficiency). In the past, we’ve been hyper-focused on estrogen, “the younger sister.” However, we now know that estrogen and progesterone must balance each other. Ignoring one and treating the other in isolation will create hormone dysregulation and imbalance.

Lower progesterone levels are a natural part of aging. To keep hormones in a healthy balance as we age, we need to focus on gut health, thyroid health, sugar regulation, stress reduction, and appropriate nutrition. While progesterone, and other sex hormones, will still naturally decrease, all of these health and lifestyle factors will help maintain hormonal balance. You can have lower levels of hormones, still feel great, and have vibrant health, if your hormones are balanced.

You can have lower levels of hormones, still feel great, and have vibrant health, if your hormones are balanced.

Symptoms of Progesterone Deficiency

These symptoms will sound all too familiar to many women out there who are experiencing hormone imbalance:

  • Anxiety
  • Bone thinning (osteopenia)
  • Heavy periods
  • Inflammation
  • Insomnia
  • Irritability and hypersensitivity
  • Low libido
  • Migraine headaches (especially during a woman’s cycle)
  • Mood swings
  • Nervousness
  • Pain
  • Weight gain

One misconception about hormonal health that I often encounter is that only estrogen is involved in bone health. However, estrogen and progesterone in balance are both critical for healthy, strong bones.

Moreover, low progesterone – not low estrogen – is one of the reasons why women begin experiencing heavier periods either after pregnancy or as they age.

Causes of Low Progesterone

  • High saturated fat intake
  • High sugar diet
  • Hypothyroidism
  • Nutrient deficiencies
  • Some pharmaceutical medications
  • Stress

Certain medications can cause progesterone deficiency. For example, antidepressants can cause your progesterone to be low. This is unfortunate because antidepressants are often given to woman to help with anxiety, which is induced by low progesterone. When we give women an SSRI like Zoloft or Prozac, we can actually cause a feed forward cycle and make a hormone deficiency worse by further lowering progesterone.

Hypothyroidism can cause low progesterone, as well as certain nutrient deficiencies such as vitamin A, vitamin B6, vitamin C, and zinc.

In some women, eating too much saturated fat can cause low progesterone. However, I’d like to add a caution here since many of us have been taught for years to avoid fat. We do need some saturated fat in our diet and inadequate amounts can also affect our hormones.

Addressing Low Progesterone

Lifestyle Medicine

The best place to begin in addressing a progesterone imbalance is to work on general health and resilience. Returning to the point I made above: You can have lower levels of hormones, still feel great, and have vibrant health, if your hormones are balanced. If you’ve followed the flow of this series, beginning with the Hormone Hierarchy — first addressing cortisol, insulin, and thyroid, then your gut health — you are well on your way to balance and resilience.

For optimal hormonal health, you need a full-spectrum view of your health. We can’t just focus on thyroid, or ovaries, or on any one specific system in isolation. You are a complete whole and more than just the sum of individual systems.

Elevated Progesterone

Progesterone, like all the hormones in this series, is looking for Goldilock’s “Just Right.” It is possible to have too little or too much, and both extremes can lead to complications. However, too much progesterone is usually the result of hormone treatment, so I’ll address symptoms in that context below.

Hormonal Treatments


Most hormonal treatments currently used today are oral forms of progestin (e.g. medroxyprogesterone), which are synthetic forms of progesterone. Be very cautions of using progestins for two reasons. First, when taking an oral progestin, the dose is about 8 – 10 times what is needed to get the right physiologic levels in your blood. These high doses can stress your liver and cause your liver to make metabolic byproducts that can be pro-inflammatory and cancer-causing. The second reason for caution is that progestins (such as medroxyprogesterone) are synthetic, as opposed to bioidentical progesterone. Synthetic “equivalents” are supposed to be biologically equivalent, but ultimately they are not. The byproducts of these synthetic hormones can be harmful to your health.

Side Effects of Progestins (Synthetic Progesterone)

  • Acne
  • Bloating
  • Breakthrough bleeding and spotting
  • Breast tenderness
  • Fluid retention
  • Hair loss
  • Headaches
  • Insomnia
  • Irritability
  • Low energy
  • Low libido
  • Mood issues
  • Weight gain

Progesterone is important for breast health and stimulates breast growth. Bioidentical progesterone is breast-protective, while synthetic progestins can actually promote cancer.

While progesterone can thicken your hair, synthetic progestins can actually cause hair loss. This is how birth control pills and some other oral hormones cause hair loss. Conversely, bioidentical progesterone, if done correctly, can actually help decrease insomnia and irritability. The nuances of medicine are tricky. The devil is always in the details.


How should we treat low progesterone? I’ll summarize with three critical concepts:

  1. First and foremost, Test…Don’t Guess! Progesterone needs to be considered alongside estrogen, thyroid, insulin, and other factors to gain perspective.
  2. For the best long-term health results, only use a bioidentical hormone, not a synthetic progestin.
  3. Finally, testing afterward and periodically is important to make sure you’re not overdosing.

Symptoms of Progesterone or Progestin Overdose

Whether you’re taking bioidentical progesterone or synthetic progestins, it’s possible to take too much. What are some of the signs that you might be taking too much progesterone or progestin? You might notice:

  • Anxiety
  • Back pain
  • Bladder issues
  • Body aches (especially in the legs)
  • Carbohydrate cravings
  • Elevated sugars
  • Increased appetite
  • Increased risk for gall stones
  • Weight gain

These side effects can be mitigated if we test hormone levels after treatment and periodically. It’s so important, so I’ll say it again: Test…Don’t Guess!

Benefits of Progesterone Treatment

Even given the pitfalls noted above, there are many therapeutic advantages of using progesterone. If treatment is done correctly, the benefits can significantly improve a woman’s health and well-being:

  • Aiding weight loss
  • Improving bone health
  • Improving sleep
  • Lowering blood pressure
  • Reducing anxiety
  • Reducing inflammation
  • Reducing the risk of breast cancer
  • Reducing the risk of heart disease
  • Supporting mood
  • Thickening hair

Progesterone treatment does actually lower your risk of breast cancer if balanced appropriately with estrogen. It can reduce anxiety and treat insomnia. It can also lower your risk for heart disease, help with weight loss, and thicken your hair. Progesterone is anti-inflammatory, It can lower blood pressure, and improve bone health. There are even some interesting studies looking at progesterone and its role in improving myelination in multiple sclerosis.

Again, these are some benefits of progesterone treatment when done appropriately, with the right kind of progesterone, balanced properly with other hormones.


Progesterone plays a vital role in women’s health, offering numerous benefits from improving sleep and bone health to reducing the risk of breast cancer and heart disease. The elder sister should not be ignored and be cautious of outdated medical opinions. It’s essential to approach progesterone treatment with care, respecting the Hormone Hierarchy, prioritizing bioidentical hormones over synthetic progestins, and regularly testing hormone levels to maintain balance.

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