Dr Fiona McCulloch ND

Dr Fiona McCulloch ND Get the newest research on natural women's health, and PCOS!

I write about science-based natural medicine for women and I've been practicing in Toronto for 21 years. My undergraduate degree focused on molecular biology and genetics and my approach blends science with modern clinical nutrition. Most of all, women are the heroines of their own health journeys - it's my greatest honour to act as a guide along this path.

🔔As of today, PCOS has been officially renamed to PMOS!The new acronym stands for ✨Polyendocrine Metabolic Ovarian syndr...
05/12/2026

🔔As of today, PCOS has been officially renamed to PMOS!

The new acronym stands for ✨Polyendocrine Metabolic Ovarian syndrome✨

💖This includes the fact that PCOS is often a metabolic condition that is lifelong and impacts the entire endocrine system, which is wonderful

The name itself being focused on cysts has certainly been confusing and incorrect for a very long time.

⚠️That being said, a different acronym may create more confusion. Even though the old name was not accurate, I was not for the acronym change as PCOS/PCOM . The debate included changing the name to one that was more accurate but with the same acronym (PCOS) so it would continue to be recognized.

🤔also, we don’t fully understand the different subtypes of PCOS (yet).
For example: not everybody with PCOS has insulin resistance

😬it also sounds a lot like PMS!

⬇️What do you think?

05/11/2026

✨PCOS without Insulin Resistance aka “Lean” PCOS. Which treatments can help?

⬇️Share your experience below or ask a question!

05/07/2026

🧐Is natural progesterone always better than synthetic progestins for PCOS?

It is important to understand the differences before you decide. Not covered here: synthetic progestins also work as birth control whereas natural progesterone can often enhance fertility.

⬇️Do you have any questions about progesterone or experiences to share? Add them below!

12/01/2025

🥴Starting progesterone and having side effects? Why it can often be a bumpy start (especially if you have high estrogen levels) and what to expect over time!

It’s important to note that some people aren’t ever able to tolerate progesterone but this isn’t as common as the situation I describe here.

11/30/2025

☝️Hear these stories every day

🦋PCOS and Hypothyroid (Low Thyroid Function) have a lot of similar symptoms! 👭To make things even more confusing, it’s c...
04/10/2024

🦋PCOS and Hypothyroid (Low Thyroid Function) have a lot of similar symptoms!

👭To make things even more confusing, it’s common to have both of these conditions.

Many studies have found that patients with PCOS have a much higher incidence of thyroid disease - around 22% of patients with PCOS have Hshimoto’s thyroiditis - an autoimmune condition that affects the thyroid.

⭐️Both PCOS and thyroid conditions affect the metabolism and can be linked to inflammation which is why there is so much overlap between them

But, it’s very possible to differentiate between them - swipe through the slides to see the differences in symptoms between the two, and lab tests for each condition.

⁉️Got any questions about PCOS or Thyroid? Ask me below and I’ll do my best to answer!

❤️PCOS causes a variety of risk factors for heart disease yet it is STILL often thought of as a condition that only affe...
02/04/2024

❤️PCOS causes a variety of risk factors for heart disease yet it is STILL often thought of as a condition that only affects fertility.

February is -started a decade ago by with . Those of us in the community know of many members who have been impacted by heart disease!

👩🏻‍⚕️It’s important to start heart screening early with PCOS and keep a close eye on lipids, insulin resistance and chronic inflammation. With the right support that starts early, heart disease can be prevented.

🩺PCOS affects every system in the body and managing it is a lifelong journey. Awareness is so important - yet most patients who are diagnosed with PCOS are not told about these risks - this takes away the opportunity for patients to prevent disease! Cardiovascular disease happens gradually over time - the earlier we can prevent it the better!

⁉️Got any questions about heart health and PCOS? Ask me below and I’ll do my best to answer!

Pmid : 35118445, 32727622, 38269234, 34677405, 37937441

🤔What causes low progesterone?In order to understand how low progesterone happens it’s critical to know how progesterone...
01/13/2024

🤔What causes low progesterone?

In order to understand how low progesterone happens it’s critical to know how progesterone is made!

📆Although a small amount of progesterone is made by the adrenals, large amounts are made ONLY after ovulation. Once ovulation has occurred the follicle transforms into the corpus luteum (CL), a temporary structure which makes progesterone for two weeks. If pregnancy does not happen, the CL dissolves, the period arrives and the next cycle begins.

⚠️Ultimately, this means that ANY condition that stops or impairs ovulation will *definitely* cause low progesterone.

➡️PCOS often stops ovulation altogether or causes it to be delayed. Due to the structure of follicles in PCOS, there also may be less production of progesterone post-ovulation.

➡️Hypothyroidism can affect the corpus luteum which is a highly metabolic structure. Without thyroid hormone it may struggle to make progesterone (38190029, 1427622)

➡️Inflammatory cytokines can inhibit progesterone production from the CL (31139895, 26161038, 26161038)

➡️And in endometriosis, it’s been found that local inflammation is linked to progesterone resistance. (28423456)

➡️Stress and undereating signal danger to the brain or lack of food for reproduction. The pituitary shuts down ovulation in order to conserve energy and avoid pregnancy during times of stress or lack of food.

🩸Another factor not mentioned in the slides is that the CL needs a massive amount of blood flow ! The CL has a rate of blood flow and need for oxygen that exceeds other tissues. Membranes of the luteal cells are in close proximity to capillaries to support this need (10617764). Good circulation is likely a factor in the production of progesterone.

⁉️Got any questions about progesterone? Ask me below and I’ll do my best to answer. Keep in mind that I can’t give personal medical advice on the ‘Gram

⭕Progesterone, Progestins and Progestogens - what’s the deal?We only make significant amounts of progesterone after ovul...
12/20/2023

⭕Progesterone, Progestins and Progestogens - what’s the deal?

We only make significant amounts of progesterone after ovulation! It is made from the shell of the follicle surrounding the egg (the corpus luteum/CL) for 2 weeks then it dissolves and our levels drop until the next ovulation.

📅It’s natural to have a large amount of progesterone in the body for 2 out of every 4 weeks during the reproductive years.

A few effects of progesterone:

✅Changing the endometrial lining into a “secretory” state that opposes the effect of estrogen
✅Lowers levels of LH and testosterone ( in androgen excess/PCOS)
✅Lightens heavy menstrual bleeding
✅Essential for embryo implantation and healthy pregnancy
✅Calming effects on the brain ( GABA receptors), helps sleep
✅Antiinflammatory
and more!

Progestins are different than progesterone- but they do change the endometrial lining into a “secretory” state that opposes the effect of estrogen

However they don’t have the same effects as progesterone on many other tissues. Certain progestins have testosterone-like actions, others have estrogen-like actions and yet others have actions similar to cortisol

When it comes to risk they are all different as well.

❌Natural progesterone (without estrogen) has NOT been found to increase the risk of clot

❌The progestin-only pill used for birth control (without estrogen) has NOT been found to increase the risk of blood clot.

⚠️Injectable synthetic progestin (Depo Provera) DOES increase the risk of clot

⚠️When synthetic progestins are combined with estrogen (for example in birth control) they DO increase the risk of clot.

⚠️Different progestins have DIFFERENT clot risk when combined with oral estrogen.

⚠️Topical estrogen (ie: the patch or gel) combined with synthetic progestin has a lower risk of clot compared to when it's combined with oral estrogen.

⚠️Topical estrogen combined with natural micronized progesterone has an even lower risk of clot.

⁉️Got any questions about progesterone, progestins or progestogens? Ask me below and I’ll do my best to answer!

👩🏻‍⚕️Two Common Types of Hair Loss : Androgenetic Alopecia and Telogen Effluvium - but how can you tell the difference?...
12/14/2023

👩🏻‍⚕️Two Common Types of Hair Loss : Androgenetic Alopecia and Telogen Effluvium - but how can you tell the difference?

Hair loss is extremely common and many people will experience it in their lifetime. In many cases it’s one of these two types.

It’s possible to have both types at once but most people have a predominance of one type of the other.

⬅️Swipe through the slides to read all the details about each type of hair loss

⭐Androgenetic alopecia (also known as pattern hair loss) is common in patients with PCOS as it’s linked to higher levels of androgenic hormones like testosterone and in particular DHT which has a powerful action in the scalp and skin.

Another common time for this type of hair loss to start is in perimenopause and menopause - this is not usually related to high levels of androgens but rather a sensitivity to androgens, changes in other hormone ratios or genetics.

⏰Androgenetic alopecia tends to be a lifelong condition from the time it starts and will fluctuate depending on how different elements involved are happening.

It does respond to treatment, however and people can have significant improvements in the condition!

⭐Telogen effluvium is fully reversible once the cause is removed. However if the cause is not removed, the shedding continues on and on!

🗓️Hair loss always takes FOREVER to respond - many hairs are already preprogrammed to fall out months ahead of time (hairs in telogen) (see my last post for more info). And, hair regrowth happens at around 1 cm per month.

There are other types of hair loss such as alopecia areata (autoimmune) and many others - so if in doubt see a dermatologist or trichologist for a scalp biopsy to diagnose!

⁉️Got any questions about hair loss, treatments, tests? Ask me below and I’ll do my best to answer?

💇🏻‍♀️Strict, extreme diets and rapid weight loss are a common cause of hair loss. This is a process called “telogen effl...
12/12/2023

💇🏻‍♀️Strict, extreme diets and rapid weight loss are a common cause of hair loss.

This is a process called “telogen effluvium” and it’s delayed by 2-4 months from the event which triggers it. In this case, rapid weight loss is the trigger.

🔌Hair is a very demanding tissue energy-wise - it grows quickly and it is very expensive for the body to produce.

Rapid weight loss signals to the brain that there is not enough food in the environment, which could mean imminent starvation or something extremely dangerous for our survival.

Hair is something that the body views as expendable. If there is not enough food to eat - why use so much energy on growing hair?

👋🏻In these situations, the body rightly says “Bye, hair, see you later”

This is why hair sheds in clumps, rapidly in telogen effluvium. The good news, is this hair all regrows once the stressor has resolved.

🙄It also without saying that not giving any support to patients and telling them to “Just Lose Weight” when they are diagnosed with PCOS is NOT helpful.

This can often start patients on a journey of yo-yo dieting, eating disorders, self-blame and anxiety.

✅If anything causes anxiety, it’s that!

⁉️Got any comments or stores about diagnosis, hair loss or being told to “just lose weight?” Comment below and I’ll do my best to respond!

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