Inositol has become one of the most talked-about supplements in the PCOS community — and for good reason. But as with many popular supplements, the social media hype can outrun the actual evidence. Let me give you an honest summary.
What is inositol?
Inositol is a naturally occurring sugar alcohol found in foods like fruits, beans, grains and nuts. It plays a role in insulin signalling and is involved in several hormonal pathways. There are multiple forms, but the two most studied for PCOS are myo-inositol (MI) and D-chiro-inositol (DCI).
What does the research actually show?
The evidence for myo-inositol in PCOS is genuinely promising, particularly in women with insulin resistance. Studies have shown improvements in:
- Insulin sensitivity and fasting glucose
- Menstrual cycle regularity
- Androgen levels (testosterone)
- Ovulation rates in some women
- Outcomes in assisted reproductive technology (IVF)
The most commonly studied ratio is 40:1 myo-inositol to D-chiro-inositol, typically 4g of MI combined with 100mg of DCI daily. This appears to more closely mimic the body's natural ratio.
Who is most likely to benefit?
The evidence is strongest for women with PCOS who have insulin resistance. If your PCOS is primarily driven by other factors — such as elevated androgens without significant insulin resistance — the benefit may be more limited. This is why I always recommend discussing supplementation with your healthcare team, ideally after blood tests to understand your metabolic picture.
Is it safe?
Inositol has a good safety profile and is generally well tolerated. Some women experience mild GI symptoms (nausea, loose stools) at higher doses. It is not recommended during pregnancy without medical supervision.
My take
Inositol is one of the more promising supplements I recommend in my PCOS practice — but it's a complement to a good dietary foundation, not a substitute for it. It won't override a diet high in ultra-processed foods or compensate for other lifestyle factors. Think of it as a helpful addition, not a solution in itself. And please — always buy from a reputable brand and let your doctor know you're taking it.