Choosing Best Inositol Supplement

How to Choose The Best Inositol Supplements for Fertility, PCOS, Thyroid & More

Dr. Jolene BrightenPublished: Last Reviewed: Balancing Your Hormones, PCOS, Thyroid Leave a Comment

Inositol is a vitamin-like compound found throughout the body, where it plays a significant role in cellular signaling. It's also used as a supplement to improve fertility, help with PCOS symptoms, support thyroid health, and more.

I've seen inositol work wonders for my patients when used in combination with other lifestyle changes. The problem is that not all supplements are created equal, so if you are choosing a supplement without the help of a healthcare professional who really understands inositol, you want to make sure you know how to select an effective and safe product.

In this article, I'll share exactly what I look for so you can confidently choose the best inositol supplement for your goals.

The Best Inositol Supplements for Fertility 

Inositol supplements can support fertility for women with PCOS and even women without PCOS undergoing fertility treatments. It's been shown to increase the frequency of ovulation and even support healthy egg quality.

The reasons why inositol promotes fertility are not entirely understood, but inositol can help the body better respond to insulin, which is linked to improved fertility. 

Which Is Better: Myo-inositol or D-chiro inositol?

One thing that might be behind inositol’s effect on fertility is the fact that there’s a much higher ratio of myo-inositol (MI) to D-chiro inositol (DCI) in the ovaries, and people with PCOS tend to have less MI which throws off the balance. So, for fertility goals, you want to make sure your body has both. 

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Dosage of Inositol for Fertility

A quality inositol supplement should contain myo-inositol and d-chiro-inositol in a 40:1 ratio. The dosage of myo-inositol should be at least 2,000 mg per day, but up to 4,000 mg has been shown to be effective. When it comes to d-chiro-inositol, more isn't always better, with 50 mg appearing to be a good supportive dose.

You’ll find this dose and ratio in carefully formulated inositol supplements like Inositol Plus.

This is one case when the ratio really matters, as some research suggests that taking too much DCI worsens egg quality, so make sure you really pay attention to that ratio.

The Best Inositol Supplements for Thyroid Support

Since inositol supports healthy cell and hormone signaling, it's not surprising that it could also help your thyroid. Interestingly, its impact on blood sugar may play a role, as there's a link between insulin resistance and Hashimoto’s,an autoimmune thyroid condition.

Thyroid hormone synthesis,metabolism, and thyroid autoimmunity are all greatly affected by myo-inositol. Low MI could increase the risk of developing hypothyroidism, but supplementing with MI might help (especially when combined with selenium) and even lower thyroid antibodies associated with Hashimotos.

Inositol Dosage for Thyroid

Many of the studies on myo-inositol and thyroid tested using a minimum of 600 mg each day.

The Best Inositol Supplements for Mental Well-being and Sleep

Myo-inositol could help with mood and mental well-being for people with anxiety, although this particular benefit is less studied than some of the others. Since inositol is involved with neurotransmitter signaling, it could impact mood and feelings of calm.

One study showed that taking a high dose of inositol (12 grams) each day for four weeks helped people with panic disorder. Another study found no benefit for anxiety but noted improvement for depressive symptoms.

Some preliminary evidence suggests that MI (in combination with folic acid) may help improve sleep quality, especially for pregnant women, although more research is needed.

Inositol Dosage for Sleep and Mood

There's not enough evidence to suggest an ideal inositol dosage for sleep or well-being, so I tend to stick with 2000-4000 mg a day which is known to be well-tolerated and generally effective for some other health conditions.

The Best Inositol Supplements for PCOS and Blood Sugar Support

Myo-inositol is the most well-researched form of inositol for PCOS, with studies showing that it can help regulate insulin sensitivity, reduce testosterone production, and improve ovulation.

DCI may also be helpful for PCOS, as it seems to act synergistically with MI to improve insulin sensitivity. Insulin sensitivity is prevalent in women with PCOS and is a major contributing factor to many symptoms. As a signaling molecule, inositol could help make your cells more responsive to insulin, with studies showing that it can help lower blood sugar along with some prescription drugs.

Inositol Dosage for PCOS

A dosage of 2000-4000 mg per day of MI and DCI in a 40:1 ratio is generally suggested for PCOS.

What to Look for in Inositol Supplements

Since inositol is taken for many different reasons, there are a few things you should look for when choosing a supplement.

  • Type. There are 9 different types of inositol, but the two most studied forms are myo-inositol (MI) and d-chiro-inositol (DCI). A quality supplement will contain both of these forms.
  • Appropriate ratio. You want to make sure your supplement matches the ratio studied for effectiveness which is 40:1 MI to DCI. The total dosage of inositol you take may differ depending on why you take it, but the overall ratio should match this as alterations could impact the effectiveness and even lead to adverse outcomes (as I'll share in more detail below).
  • Dosage. The amount you take should be a therapeutic amount that matches what is studied in research for your specific condition. Too much or too little may not bring you the results you're looking for (and waste your money).
  • Quality manufacturing practices. Look for companies that use third-party testing for contaminants, which means they care about what goes into their product and that you're getting what you pay for.
  • Unnecessary fillers or harmful ingredients. You want a pure inositol supplement without fillers or additives that could potentially harm your health. For example, titanium dioxide is a common filler in supplements linked to adverse health outcomes. Cheap doesn't always mean better, so don't let price be your only determining factor.

As a healthcare practitioner, I want to feel confident that when I recommend inositol, it's in a quality product that I know will do what it's supposed to do – help my patient get results. That's why I carefully crafted my own inositol supplement that meets all of the criteria listed above to support women's health. You can learn more about Inositol Plus here.

Inositol Supplements to Avoid

When choosing an inositol supplement, look for products that contain MI or DCI. Other types of inositol molecules could have different effects on the body, and they're not nearly as well studied as myo-inositol or d-chiro-inositol.

In addition, many inositol supplements only contain myo-inositol, but as I mentioned earlier, the ratios of MI and DCI are important. Make sure you choose a product that contains both forms of inositol in the correct balance.

Finally, steer clear of any product that doesn't list the inositol content on the label. The amount of inositol in a supplement can vary widely, and without this information, you have no way of knowing if you're getting an effective dose.

When it comes to inositol supplements, more is not always better. In most cases, the dosage recommendations I've listed above are more than enough to see results, and taking too much can actually be counterproductive.

The Best Foods to Increase Inositol in Your Diet

While supplements are the best way to increase inositol levels based on research, you can also get some inositol from foods. These include:

  • Beans
  • Citrus fruits
  • Whole grains, especially brown rice and oats
  • Nuts and seeds
  • Organ meats

As always, getting your nutrients from whole foods is ideal, but if you're not able to get enough inositol from diet alone, supplements can be a helpful addition. Choosing the right supplement can make all the difference when it comes to reaping the benefits of inositol.

Looking to further support your hormones through your diet? Grab my free meal plan and recipe guide to help you get started.

Frequently Asked Questions (FAQs) About Purchasing Inositol Supplements

What Is the Supplement Inositol Good for? 

Inositol supplements have many potential benefits, as this nutrient plays a vital role in various biological processes. Inositol is involved in cellular signaling and has been shown to enhance insulin sensitivity, especially for people with PCOS. It also supports fertility and thyroid health and possibly helps with mood and well-being.

What Is the Best Form of Inositol to Take? 

The best form of inositol to take depends on the condition you're trying to treat, but myo-inositol and d-chiro-inositol are the most well-studied forms. A dosage of 2,000 mg per day of MI and 50 mg of DCI, which is a 40:1 ratio, is generally suggested for PCOS. When it comes to inositol supplements, more is not always better.

Can You Take Inositol Every Day? 

Yes, you can take inositol every day, and it works best to take it consistently. Inositol is considered safe, but if you take certain medications for blood sugar or mental health, it's important to check with your doctor before starting inositol supplements, as they may interact with these medications.

Which Inositol Brand is Best for Women's Health? 

The best inositol brand contains myo-inositol and d-chiro-inositol in the correct ratio, is free of unnecessary fillers and binders, and is manufactured in a facility that follows ethical manufacturing practices—so it does what it's supposed to do for you!

Inositol from Food

Key Takeaways

  • Inositol is a supplement that can be helpful for PCOS, fertility, thyroid health, and more.
  • When choosing an inositol supplement, make sure it contains myo-inositol and d-chiro-inositol in the correct ratio.
  • In most cases, a dosage of 2000 mg of myo-inositol and 50 mg d-chiro-inositol per day is enough to see results.
  • You can take inositol every day, but it's important to check with your doctor if you're taking medications for blood sugar or mental health.
  • The best inositol brand is one that contains myo-inositol and d-chiro-inositol in the correct ratio, is free of fillers and binders, and is manufactured in a facility that follows ethical manufacturing practices.

Now that you know more about inositol and how to choose the best supplement, you can give it a try and see if it makes a difference for you. As always, check with your doctor before starting any new supplement, especially if you're pregnant or breastfeeding.

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About The Author

Dr. Jolene Brighten

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Dr. Jolene Brighten, NMD, is a women’s hormone expert and prominent leader in women’s medicine. As a licensed naturopathic physician who is board certified in naturopathic endocrinology, she takes an integrative approach in her clinical practice. A fierce patient advocate and completely dedicated to uncovering the root cause of hormonal imbalances, Dr. Brighten empowers women worldwide to take control of their health and their hormones. She is the best selling author of Beyond the Pill and Healing Your Body Naturally After Childbirth. Dr. Brighten is an international speaker, clinical educator, medical advisor within the tech community, and considered a leading authority on women’s health. She is a member of the MindBodyGreen Collective and a faculty member for the American Academy of Anti Aging Medicine. Her work has been featured in the New York Post, Forbes, Cosmopolitan, Huffington Post, Bustle, The Guardian, Sports Illustrated, Elle, and ABC News. Read more about me here.