A Note Before We Begin
PMOS (Polyendocrine Metabolic Ovarian Syndrome) is one of the most misunderstood diagnoses in women’s health. If you’ve recently received this diagnosis, you may be surprised — many women with PMOS have regular periods, no obvious symptoms, and no idea that this condition applies to them until a routine ultrasound or bloodwork tells them otherwise.
In over 25 years of clinical practice, I rarely see PMOS as a black-and-white condition. Most women exist somewhere in the grey zone — a little of this symptom, a little of that one, with presentations that vary enormously from person to person. For a fuller picture of what PMOS actually is and how it presents, I’d encourage you to read The Complete PMOS Guide before diving into supplements.
Drew has 25 years of clinical experience treating fertility and pregnancy-related conditions, and has spent 18 years training acupuncturists and other healthcare practitioners across Ontario in Traditional Chinese Medicine techniques — including Naturopathic Doctors & Medical Doctors .
One more important note: if you are taking any supplements and receive a positive pregnancy test, speak immediately with your prescribing practitioner to confirm what is safe to continue during pregnancy. This applies to everything covered in this article.
Lifestyle First — No Supplement Can Do What This Does
Before getting into supplements, this needs to be said clearly: lifestyle factors are the most powerful tools available for managing PMOS — and no supplement comes close to replicating their effect.
Regular exercise and a diet that minimizes refined grains and processed sugars are foundational. PMOS is fundamentally a condition involving insulin resistance and hormonal dysregulation, and maintaining stable blood sugar levels through diet and movement addresses the root issue in a way that supplements simply cannot.
If you’re not addressing lifestyle, supplements become significantly less effective. Think of them as support — not the solution.
A Note on Metformin
Metformin is a prescription medication commonly used in the management of PMOS, particularly for women undergoing IUI or IVF. It works by improving insulin sensitivity and is often used successfully in fertility treatment settings. It can be tough on the digestive system for some women, but remains an important medical option. If you haven’t discussed Metformin with your doctor, it’s worth raising — it is entirely separate from the supplement options covered here and falls under the care of your medical doctor.
Myo-Inositol — The Most Research-Backed PMOS Supplement
Myo-Inositol is the supplement with the strongest research base for PMOS, and it’s the one I reach for most consistently in clinical practice. It works by improving insulin signalling — a 2017 meta-analysis of randomized controlled trials found that myo-inositol supplementation significantly reduced fasting insulin levels and insulin resistance in women with PMOS, alongside improvements in hormonal balance including reductions in testosterone and increases in SHBG. A systematic review and meta-analysis of randomized controlled trials further found that myo-inositol supplementation significantly increased clinical pregnancy rates and top-grade embryo rates in women with PMOS — supporting its role in improving egg quality.
You may have seen products combining Myo-Inositol with D-Chiro Inositol. While D-Chiro Inositol has its own reearch base, the additional clinical benefit over Myo-Inositol alone in most women is modest — and the cost difference is significant. In clinical practice, Myo-Inositol on its own remains the more practical and cost-effective first choice for most women with PMOS.
A realistic expectation: nothing moves quickly in this field. Inositol requires consistent use over time — the hormonal benefits in the meta-analysis were only significant after at least 24 weeks of use. Patience is part of the protocol.
Berberine — Nature’s Metformin (With Important Distinctions)
Berberine is a natural compound derived from several plants and has earned the informal nickname ‘nature’s metformin’ due to its similar mechanism of action — improving insulin sensitivity and helping regulate blood sugar levels. A meta-analysis of randomized controlled trials found no significant difference between berberine and metformin in alleviating insulin resistance or improving glycolipid metabolism in women with PMOS. A systematic review of 12 randomized controlled trials found berberine significantly reduced total testosterone and LH/FSH ratio compared to placebo — with effects on metabolic markers comparable to metformin in several outcomes.
To be clear: Berberine is not Metformin. It does not have the same depth of clinical research behind it, and it is not a replacement for a medication prescribed by your doctor. However, for women looking for a natural approach to blood sugar regulation in the context of PMOS, the research on berberine is genuinely interesting — particularly given its comparable effects on insulin resistance and androgen levels in the available trials.
One important note: Berberine is not recommended during pregnancy. If you receive a positive pregnancy test while taking Berberine, speak with your practitioner immediately about whether to continue.
NAC (N-Acetyl Cysteine) — Versatile and Underrated
NAC is one of those supplements that keeps appearing across multiple fertility conditions — and PMOS is no exception. As a powerful antioxidant, NAC helps address the oxidative stress that is commonly elevated in women with PMOS. A 2025 systematic review and meta-analysis of 22 studies involving 2,515 women found that NAC was associated with statistically significant increases in progesterone and endometrial thickness in women with PMOS — supporting follicular development and ovulation through its antioxidant and insulin-sensitizing properties. A meta-analysis of 18 studies involving 2,185 participants further found evidence supporting NAC’s role in ovulation induction and pregnancy rates in women with PMOS.
What makes NAC particularly interesting is its broader applicability. Beyond PMOS, research has highlighted its potential benefits for egg quality and endometriosis — making it one of the more versatile tools in a fertility supplement protocol. For women with PMOS who are also concerned about egg quality or have co-existing endometriosis, NAC addresses multiple areas with a single supplement.
As with all supplements covered here, dosage matters significantly — and the right amount for your situation is best determined with the guidance of an experienced practitioner.
Spearmint Tea — A Simple and Gentle Option
Spearmint tea may not be the first thing that comes to mind when researching PMOS supplements, but a small number of studies have found it may help reduce androgen levels — the elevated male hormones that contribute to some of the more visible PMOS symptoms like excess hair growth and acne.
The evidence base is modest and this is not a primary intervention, but for women looking for gentle, low-risk additions to their protocol, spearmint tea is a reasonable and accessible option.
Magnesium — Often Overlooked, Worth Considering
Magnesium deficiency appears to be common in women with PMOS. A cross-sectional analysis of 1,000 women with PMOS found that those with higher serum magnesium levels had significantly lower fasting glucose, insulin resistance scores, and testosterone — suggesting that magnesium status may be meaningfully connected to the metabolic and hormonal features of PMOS.
Whether supplementing directly improves these markers is less settled. A systematic review of randomized controlled trials found that magnesium supplementation alone did not produce significant improvements in inflammation, oxidative stress, or metabolic markers in women with PMOS — though combinations with other supplements showed more promise and the general evidence base for magnesium improving insulin sensitivity is stronger.
What is well established is magnesium’s broader role in hormonal health, sleep quality, and stress regulation — all of which are relevant to PMOS management. Given how common magnesium deficiency is generally, and how inexpensive and well-tolerated magnesium supplements tend to be, it remains worth discussing with your practitioner — particularly if sleep disruption, stress or constipation are part of your picture.
Chromium — Blood Sugar Support
Chromium is a trace mineral that plays a role in insulin function and blood sugar regulation. Some research has found that chromium supplementation may improve insulin sensitivity in women with PMOS, complementing the dietary and lifestyle approaches mentioned earlier.
The evidence is not as robust as for Myo-Inositol or Berberine, but chromium represents a reasonable addition to a comprehensive PMOS supplement protocol — particularly for women whose primary concern is blood sugar regulation.
The Bottom Line
PMOS is a complex, highly individual condition — and the grey zone is where most women actually live. No two PMOS presentations are identical, which means no two supplement protocols should be identical either.
The supplements covered in this article represent some of the most research-backed options available. But dosage matters, timing matters, and your individual presentation matters most of all.
Exercise regularly. Minimize refined grains and processed sugars. Address blood sugar stability through lifestyle first. Then consider supplements as part of a broader, personalized approach — ideally guided by a practitioner who understands both the research and your specific situation.
This is the third article in the fertility supplement series. Read the first article: Fertility Supplements — What You Really Need to Know and the second: Egg Quality Supplements — What the Research Actually Says