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 PCOS1 and even women without PCOS undergoing fertility treatments2. 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 myoinositol which throws off the balance. So, for fertility goals, you want to make sure your body has both.
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 Myoinositol Plus.
This is one case when the ratio really matters, as some research3 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 resistance4 and Hashimoto’s, an autoimmune thyroid condition.
Thyroid5 hormone synthesis,metabolism, and thyroid autoimmunity are all greatly affected by myo-inositol. Low myoinositol could increase the risk of developing hypothyroidism, but supplementing with myoinositol6 might help (especially when combined with selenium) and even lower thyroid antibodies associated with Hashimotos.
Inositol Dosage for Thyroid
Many of the studies7 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 study8 showed that taking a high dose of inositol (12 grams) each day for four weeks helped people with panic disorder. Another study9 found no benefit for anxiety but noted improvement for depressive symptoms.
Some preliminary evidence suggests that myoinositol (in combination with folic acid) may help improve sleep quality10, 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 2,000 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-inositol11 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 myoinositol 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 insulin12, with studies showing that it can help lower blood sugar along with some prescription drugs13.
Inositol Dosage for PCOS
A dosage of at least 2,000 mg per day of MI and DCI in a 40:1 ratio is generally suggested for PCOS. In addition, women with PCOS may also benefit from vitamin D, vitamin B6, chromium in improving symptoms. For optimal testosterone balance, zinc, spearmint, fenugreek, nettle root, and green tea extract have been shown to be helpful in supporting the body in creating optimal levels. You'll find these ingredients as part of our comprehensive Myoinositol Plus by Dr. Brighten formula.
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.
- 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 dioxide14 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 Myoinositol 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 Myoinositol Plus by Dr. Brighten contains myo-inositol and d-chiro-inositol in the correct ratio, plus additional ingredients that support optimal blood sugar and hormone health. It is well recognized that vitamin B6, vitamin D, chromium, and zinc are supportive of women's hormones. We've included these, plus herbs specifically formulated with androgen balance in mind. Our product 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! The ingredients are sustainably sourced, we use environmental conscious package, and manufactured in the United States. We also commit to third party testing to ensure that we are providing the best quality supplement to our community.
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 2,000 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.
References
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5655679/ ↩︎
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5728865/ ↩︎
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3447676/ ↩︎
- https://www.researchgate.net/publication/312218518_Insulin_resistance_in_the_patients_with_euthyroid_Hashimoto_thyroiditis ↩︎
- https://pubmed.ncbi.nlm.nih.gov/30506520 ↩︎
- https://www.frontiersin.org/articles/10.3389/fendo.2021.662582/full ↩︎
- https://www.frontiersin.org/articles/10.3389/fendo.2021.662582/full ↩︎
- https://pubmed.ncbi.nlm.nih.gov/9169302/ ↩︎
- https://www.ncbi.nlm.nih.gov/books/NBK184852/ ↩︎
- https://pubmed.ncbi.nlm.nih.gov/32933356/ ↩︎
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5655679/ ↩︎
- https://www.hindawi.com/journals/ije/2018/1968450/ ↩︎
- https://pubmed.ncbi.nlm.nih.gov/30614282/ ↩︎
- http://www.eurekaselect.com/article/74473 ↩︎
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