PCOS and Inositol: Everything You Need to Know

Aug 13

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Hi there,

It’s been a while since I wrote a blog post but after filming the video below on inositol, I knew I wanted to create a companion post so those of you who prefer to read this type of information will have it. Alright, let’s get right into it.

What is Inositol?

Inositol is a naturally-occurring sugar alcohol. Previously, it was classified as a B vitamin (Vitamin B8 to be exact) but because our bodies can and do produce it from glucose, it’s not an essential nutrient (meaning we don’t have to get it from an outside source because we can make it in ample amounts.)

There are nine different types of inositols. Myo-inositol is the most prevalent type in food and in our bodies. In fact, about 99% of the inositol in our bodies is myo-inositol. The remaining 1%, is D-chiro inositol. D-chiro-inositol is made in our bodies by converting myo-inositol into D-chiro inostiol. This conversion is carried out by epimerase, an insulin-dependent enzyme. Keep that in mind. It’ll be really important to what we’ll discuss in the last section.

What foods contain inositol?

Many plant-based foods contain high amounts of myo-inositol. Beans, seeds, nuts, grains, and fruit are where we’ll find the highest concentrations. More specifically, citrus fruit, cantaloupe, great northern beans, and stone-ground wheat have the richest sources.

Side note- as you can see, many of the richest sources are also carb-rich foods. Foods that, unfortunately, often get demonized for being high in carbohydrates. But remember, when we restrict carbohydrate-rich foods, we don’t only end up eating fewer carbohydrates, we also end up eating less of the other nutrients that are found in those foods. Things like fiber, phytonutrients, vitamins, minerals, antioxidants, nutrients with anti-inflammatory properties, and myo-inositol. Plus we miss out on the freedom and joy that comes from eating a wide variety of foods. I think it’s always a better idea to focus on increasing fiber, fat, and protein-rich foods to balance out carbohydrates than it is to eliminate or limit carb-rich foods.

What are the benefits of inositol supplementation for PCOS?

Research has shown, supplementing with inositol can:

improve insulin sensitivity
decrease androgens and the associated symptoms of hyperandrogenism like acne and hirsutism (facial and body hair growth)
improve menstrual regularity
improve egg quality
promote ovulation
decrease LH and improve FSH/ LH ratio
reduce the risk of developing gestational diabetes
improve triglyceride levels

In addition to the benefits above, my clients have reported improved mood, energy, and cravings.

How much inositol should be taken?

The therapeutic dose for inositol for PCOS is 2-4g. Most of my clients take around 4g/ day. Some start off taking a lower dose, Then, we slowly increase if they are prone to hypoglycemia (low blood sugar), are already taking an insulin sensitizer (like metformin), or have a sensitivity to sugar alcohols.

Should I take D-chiro, Myo, or Myo and D-chiro together? Which is best?

In the past, I recommended myo: d-chiro combined in a 40:1 ratio and kind of poo pooed on Myo alone. After taking a closer look at the research, I now recommend either myo-inositol alone or myo and d-chiro combined. Both have great research behind them.

Myo-inositol alone tends to be less expensive than myo and d-chiro combined, so if budget is a major consideration for you, it might be best to go with myo-inositol alone.

On the other hand, myo combined with d-chiro tends to be more expensive but is possibly more effective than myo alone. But that doesn’t mean myo alone is ineffective.

I don’t recommend taking D-chiro inositol alone because there have been some studies that showed alone, in high doses, it can have negative effects on egg quality.

And just in case you were wondering where the 40:1 ratio came from, that’s the ratio we find in plasma. So supplementing at that ratio is simply to mimic plasma concentrations. Other ratios have been tried, but the results weren’t the best.

What brands of inositol do you recommend?

If my clients have decided to take myo-inositol alone, I recommend Jarrow. If they’re going to take myo/ d-chiro combined, I recommend Theralogix Ovasitol.

I always recommend buying supplements directly from the manufacturer or one of their authorized retailers, which you can find on their websites.

If you decide to take Theralogix, you can use PRC code 100368 at checkout for preferred pricing.

What are the side effects?

The most common side effects with inositol are related to the gastrointestinal tract, including things like gas, nausea, and diarrhea. Which makes sense considering the fact that it’s a sugar alcohol.

Are there any safety concerns with inositol? Can it be taken while pregnant or taking other medications and supplements?

Inositol is safe to take while trying to conceive, during pregnancy, and when taking other supplements and medications. Of course, it’s always a good idea to discuss supplements with your personal healthcare team including your dietitian, primary care provider, any specialists, and your pharmacist.

To my knowledge, safety has not been established in breastfeeding but it also hasn’t been shown to be unsafe.

How does inositol work in the body in people with PCOS?

Inositol works as a second messenger for a number of hormones (first messengers) including thyroid-stimulating hormone, follicle-stimulating hormone, and insulin. We’ll take a closer look at how it works with insulin to paint the picture of how it works in our bodies.

In response to our blood sugar rising, insulin is released. Insulin then binds to receptors on our cells. When this happens, second messengers are released. Some of those second messengers are made from inositol.

If all goes as expected, our glucose (sugar) enters our cells, and our blood sugar and insulin levels lower. But things don’t always go as expected.

Sometimes, the cell doesn’t respond to insulin properly. This can result in high blood sugar and high insulin levels as the body continues to produce more and more insulin in an attempt to lower the blood sugar.

In the case of PCOS, there seems to be some dysregulation in inositol metabolism. With insulin resistance, d-chiro and myo-inositol are over excreted in the urine, leading to inadequate amounts of inositol available to make those ever-important second messengers.

Now, recall what I said earlier about D-chiro inositol being converted from myo-inositol by epimerase, an insulin-dependent enzyme.

With insulin resistance, epimerase isn’t activated to the degree that we need it to. Which means myo-inositol doesn’t get converted to D-chiro inositol and we end up with too much myoinositol and not enough d-chiro inositol. Which exacerbates insulin resistance.

Here’s where it can get a little tricky. Everything that I just said about insulin resistance doesn’t apply to the ovaries. It applies to the liver, muscle, and fat cells. The ovaries, on the other hand, remain sensitive to insulin even when the peripheral cells become insulin resistant.

So what happens is, the cells in the ovaries get overstimulated by the rising insulin. This is where epimerase comes back into the picture.

In the ovaries of someone with insulin resistance, the epimerase is over activated and over converts myo-inositol to d-chiro inositol. And too much D-chiro inositol in the ovaries is associated with high androgen levels and poor egg quality.

This combo of too much d-chiro inositol and too little myo-inositol in the ovaries, but too much myo-inositol and too little d-chiro inositol in the fat, liver, and muscle cells is known as the DCI paradox of the ovaries.

So by supplementing with inositol, we can hopefully replete the inositol that is lost in the urine and restore the ideal ratio.

Whew! That was a lot! I hope you enjoyed it and I hope it answered your questions about inositol for PCOS.

Be well,

Kendra