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Ovasitol For PCOS: A Scientific Review

Kym Campbell

By Kym Campbell, BSc. | Updated March 18th, 2024

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Key Takeaways

Ovasitol is a combined myo-inositol and d-chiro-inositol supplement for PCOS patients. The 40:1 formulation used is superior to competitor products.

The benefits are well-proven in the treatment of insulin resistance and infertility. It is safe to take during pregnancy.

The benefits of Ovasitol are enhanced by a PCOS-friendly diet. Get started today by joining my free 30-Day PCOS Diet Challenge or by downloading this free 3-Day Meal Plan.

Ovasitol by Theralogix is the market leader in PCOS inositol products.

I was once skeptical of the added value of Ovasitol compared to other formulations. In this article, I explain why I changed my mind. I now recommend this product to women that take part in my free 30-Day PCOS Diet Challenge and Beat PCOS 10-Week Program.

The Benefits Of Inositol

Inositol supplements are well-studied in patients with polycystic ovary syndrome. As I’ve written about in detail here, inositol has the following benefits:

  • Inositol improves insulin sensitivity and hormone balance in both lean and overweight women with PCOS [1-4].
  • Myo-inositol may be as good as metformin for improving insulin sensitivity and testosterone [5, 6, 30].
  • Because of its impact on insulin, inositol can help reduce sugar cravings. This makes it easier to follow a PCOS diet. I see this a lot in my PCOS support group.
  • Myo-inositol helps restore normal ovarian function and more regular menstrual cycles [7]. It can also increase egg quality [8-9].
  • Studies on women receiving fertility treatments have shown increases in pregnancy rates [10-13]. Supplementation also reduces the risk of ovarian hyperstimulation syndrome [9].
  • Myo-inositol has also been shown to have modest benefits for acne [14], hirsutism [15], and weight loss [7, 16]. The size of the effect here is not likely to be life-changing though.

There are ingredients to be wary of when choosing products. And there are some types of inositol you may want to limit when trying to conceive. But if a product contains 4,000 mg/day of myo-inositol, then there are health benefits to be had. This is the typical recommended dose for PCOS.


Daily inositol supplementation can help restore healthy hormone levels in PCOS patients. This can impact a wide range of systems relating to both fertility and metabolic health.

Criticism Of 40:1 Combined Therapy Myo-inositol

Ovasitol by Theralogix is a combination product. It contains 40 parts of myo-inositol for every 1-part D-chiro-inositol. Dosing is 2,000 mg of myo-inositol + 50 mg of D-chiro-inositol, taken twice daily.

Both Theralogix and the scientific community have long said that a 40:1 ratio is the best for PCOS [17-19].

Back in 2017, I was skeptical of this claim. When I looked at the data, all these perspectives were informed by only two randomized controlled trials [20, 21]. Each with shortcomings and limitations.

Other experts had noted that a 40:1 ratio, “seems arbitrary”. They also said that “without further scientific evidence, the 40:1 ratio has no reason to be considered preferable to other available formulations” [22].

A 2019 study dampened these concerns.


Before 2019, many experts raised concerns about the over-emphasis on treatment with a 40:1 combined inositol supplement. This ratio was considered “arbitrary”.

The Study That Changed My Mind

Nordio and colleagues tested various ratios of myo- and D-chiro inositol in women with PCOS. They looked at ratios of 1:3.5, 2.5:1, 5:1, 40:1, and 80:1. They also tested D-chiro inositol alone. Out of all these combinations, they found that a 40:1 formulation was best at restoring ovulation and improving fertility [23]. This randomized, open-label comparison trial made me change my mind.

I now think that products like Ovasitol are the best formulation for women with PCOS. Ovasitol’s 40:1 ratio of inositol isomers has been demonstrated in mouse models of PCOS. It’s also been tested in other clinical trials [23-25].


Recent comparative trials have shown that a 40:1 ratio of myo- and D-chiro inositol is superior for the treatment of PCOS. Ovasitol is the market-leading supplier of this type of inositol supplement.

Cheapest Places To Buy Ovasitol

You can buy Ovasitol on Amazon. Many pharmacies also stock it. For the best deal though, you should buy it directly from your local distributor.

USA: US customers can buy Ovasitol from Theralogix here. Use the link provided or type in the Provider Referral Code (PRC) A29927 at checkout. This will get you $14 off the retail price for a 90-day supply.

Canada: Canadian customers can purchase Ovasitol directly from Theralogix Canada here. Use the link provided or type in discount code KYM at checkout for $10 off the retail price. Please note that your discount will only show up at the final stage of checkout.

When Is Inositol Worth Taking?

If you’re struggling with infertility or insulin resistance, then inositol is well worth considering. Especially if you’re already taking insulin-sensitizing prescription medications.

When used as directed, inositol supplements are safe. So much so, that women with PCOS are sometimes advised to take myo-inositol during pregnancy [26-28]. The ingredients used in Ovasitol are naturally present in the body. This means that the downside risk is low. It’s also fairly affordable, as results are typically observed within 3 – 6 months.


Inositol supplements, like Ovasitol, are suitable for the majority of people with PCOS. This is a safe, effective, and relatively affordable PCOS treatment.

How To Enhance The Benefits Of Ovasitol For PCOS

Dietary supplements like Ovasitol are only one of many evidence-based PCOS natural treatments. The way to get the best results with Ovasitol is to change your diet too. This helps address the underlying mechanisms that cause PCOS. Switching to the best macros for PCOS, for example, can reverse insulin resistance. Eliminating foods like gluten, dairy, and sugar reduces inflammation. While each change on its own is small, collectively, they make a big difference.

To start putting a PCOS diet into practice, sign-up for my free 30-Day PCOS Diet Challenge. Or get started today with this free 3-Day Meal Plan.


The benefits of nutritional supplements, like Ovasitol, are much greater when combined with a PCOS-friendly diet.

The Bottom Line

Ovasitol is a safe and effective PCOS treatment. While the marketing claims are many, there is good scientific evidence supporting its use. Recent evidence shows that the 40:1 formulation used in Ovasitol is superior to competitor products. For PCOS women struggling with infertility or insulin resistance, then inositol supplements are well worth considering.

Whether you take inositol or not, dietary change is essential for getting your PCOS in check. Start this process by signing up for my free 30-Day PCOS Diet Challenge. Or begin today with this free 3-Day Meal Plan.


What is the Ovasitol dosage for PCOS? Ovasitol is an unflavored inositol powder. It comes either in a canister or in individual packets. A single dose is one leveled scoop from the canister, or one packet.

How long do I need to take Ovasitol? At least 3 months is recommended. By 6 months, most benefits will be realized. Discontinuation may cause symptoms to return unless you’ve made diet and lifestyle changes in the meantime.

Do I need a prescription for Ovasitol? No. Inositol is a nutritional supplement that’s available over the counter.

What are the side effects? No relevant adverse effects were found in several studies that used 4000 mg per day of myo-inositol throughout pregnancy [28, 29].

Can I take Ovasitol with Metformin? Myo-inositol-containing supplements can improve insulin sensitivity as much as metformin [5, 6, 30]. Caution is warranted when taking both of these medicines together. Your metformin dose may need to be reduced or ceased.

Ready to Take Action?

  • Join my free 30-Day PCOS Diet Challenge here. This is a unique program where you'll receive weekly meal plans, shopping lists, and helpful video lessons. You'll also be part of a motivated and inspiring community of like-minded women.

  • Download my free 3-Day PCOS Diet Meal Plan here. This is perfect for getting started if you aren't ready to commit to 30 days.

  • Join my PCOS Monthly Meal Planning Service here. This service includes hundreds of PCOS recipes within a pre-populated, yet customizable meal plan. It's designed to save you time and help you apply a PCOS diet.

  • Sign up for my Beat PCOS 10-Week Program. This is a comprehensive program that covers diet, PCOS-centric emotional eating, exercise, stress management, and much more. All within a support group environment. The 10-Week Program includes the same recipes and meal plan as my monthly meal planning service.


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