Living with polycystic ovary syndrome (PCOS) can be exhausting. On top of symptoms such as weight gain, infertility, and metabolic conditions, the journey toward diagnosis and treatment is often long, frustrating, and confusing. Together, these challenges result in a significantly lower quality of life across multiple metrics, such as social functioning and mental health.
One potential treatment that has gained attention is inositol. Inositol is a naturally occurring molecule that can be taken as a supplement and has been the subject of multiple studies and randomized controlled trials as a remedy for PCOS.
Read on to learn some of the most important research findings—what inositol is, how it works, and whether it might be a viable treatment option for PCOS.
Why have people tried using inositol to treat PCOS?
Although it is not part of established diagnostic criteria, 50-90% of people with PCOS experience insulin resistance, as PCOS and insulin resistance perpetuate each other in a vicious cycle. When people with PCOS struggle with weight issues, it is often due to insulin dysregulation. Not only can insulin resistance contribute to PCOS symptoms, but it also raises the risk of long-term health conditions.
Read more about PCOS and insulin resistance here.
Given the impact of insulin resistance and its downstream effects, one medication often considered part of an overall approach to PCOS is metformin. Metformin is a medication that improves insulin sensitivity in part by decreasing glucose production in the liver. While this medication is relatively well tolerated, some patients have side effects or seek additional treatment options.
Like metformin, inositol is an insulin sensitizer. Researchers hypothesize that this supplement could be an additional treatment option that simultaneously addresses insulin resistance symptoms and improves fertility and reproductive outcomes in PCOS patients.
What is inositol?
Inositol is a sugar that is structurally similar to glucose. The human body can naturally synthesize it from a form of glucose in the kidneys, liver, and other tissues. It is found in various foods, including but not limited to grapefruit, peanuts, and green beans. Inositol can also be taken as an oral supplement.
There are nine different types of inositol, known as isomers. The most common isomer is myo-inositol, while the second most common is D-chiro-inositol. Both molecules are part of complex signaling pathways that regulate blood sugar and play a role in reproductive function.
Myo-inositol promotes fertility by enabling follicle-stimulating hormone (FSH) signaling, which prompts egg cell maturation. Meanwhile, D-chiro-inositol, usually present at much lower levels, helps ovarian cells synthesize normal amounts of androgens.
In healthy people, Myo-inositol and D-chiro-inositol exist in a specific ratio. However, recent research has revealed that people with PCOS tend to have too much or too little of one of the isomers. Scientists hypothesize that this imbalance of inositol ratios in PCOS patients affects fertility, androgen levels, and other symptoms of PCOS.
Does inositol work for PCOS?
Following the discovery of altered inositol metabolism in PCOS patients, scientists hypothesized that supplementation could help restore the healthy ratio of inositol isomers to relieve PCOS symptoms. In recent years, research groups worldwide have conducted a wide range of studies to assess the therapeutic potential of inositol in people with PCOS.
Current research consensus indicates that treatment with myo-inositol, D-chiro-inositol, or a combination thereof can potentially improve ovarian function, hormonal imbalances, and glycemic regulation in people with PCOS. However, study results have varied; some show significant improvements, and others show only minor effects. The positive results highlighted below will need to be confirmed by additional research in the years to come.
Stabilizing metabolic health and improving some associated symptoms
In randomized controlled trials, myo-inositol, D-chiro-inositol, and combination inositol treatments have mitigated the effects of insulin resistance as measured by glucose-to-insulin ratios and fasting insulin.
Scientists remain unsure whether inositol supplementation directly impacts insulin signaling and sensitivity at a molecular level or indirectly through altering cascading pathways. Moreover, the strength of inositol’s impact on insulin and downstream effects has varied across randomized controlled trials, with some showing little to no change.
Metabolic pathways are incredibly complex, and no silver bullet can address every symptom or correct every imbalance. Inositol could be considered as part of a comprehensive approach to address glucose and insulin management.
Improving reproductive health
Since PCOS is one of the most common causes of female infertility, Myo-inositol, often in combination with folic acid, has been extensively studied as a treatment for improving reproductive health in PCOS because of its role in FSH signaling (mentioned above). D-chiro-inositol has also shown some promise.
Clinical studies have indicated that inositol can:
- Restore or improve ovulation and regular menstruation. Combined treatment with myo-inositol and folic acid increased ovulation and caused a majority of PCOS patients with infertility to develop menstrual cycles—70% of subjects in one large observational study and 100% in a small controlled study.
- Improve cellular quality of eggs and embryos in patients undergoing assisted reproduction via in vitro fertilization (IVF) or other approaches. Multiple studies demonstrate that including myo-inositol supplementation in both IVF and ICSI for PCOS patients significantly increased the number of large, mature egg cells available for harvesting and sped up the in vitro embryo development process, making it easier and more efficient to obtain blastocysts for implantation.
- Help prevent and treat gestational diabetes in PCOS patients who become pregnant. Treatment with myo-inositol reduced risk by more than 80% and improved blood sugar regulation in patients who had already developed gestational diabetes.
Despite these promising results, data is still lacking regarding the most crucial fertility outcomes: pregnancy and live birth rates. Most studies so far have not followed patients to a birth endpoint. Multiple papers point out this shortcoming in the field, so new studies will hopefully fill that critical gap soon.
Alleviating psychological symptoms associated with PCOS
Inositol may help address the psychological challenges of PCOS in two ways: directly, by facilitating signaling in the brain, and indirectly, by improving PCOS symptoms that often lead to depression.
Inositol has been studied as a psychiatric treatment separate from PCOS because it is involved with a messenger system in the brain. Randomized controlled trials showed that inositol treatment could improve depression and anxiety, as evidenced by decreased panic attacks and lowered scores on depression assessments.
Many PCOS patients experience depression. Scientists acknowledge that a multitude of factors may contribute to this, including body image, struggles with fertility, hormonal imbalances, and low vitamin D. Based on the reproductive and metabolic benefits demonstrated across multiple studies, some researchers have suggested that inositol may be able to produce indirect psychological benefit in addition to direct neurophysiological effects by improving troublesome physical symptoms. However, there have not yet been any randomized controlled trials that specifically examined the psychological impact of inositol supplementation on PCOS patients.
Lowering androgen (i.e., testosterone) levels
Inositol supplements have also lowered androgen levels and rebalanced ratios of other sex hormones in PCOS patients compared to placebo treatments in some studies. This decrease in androgens has been shown to have downstream positive effects on androgen-related symptoms such as increased body hair, alopecia, weight gain, and acne.
Is inositol a safe treatment for PCOS?
Myo-inositol is a generally safe compound tolerated well by many patients with minimal possible side effects at standard doses.
The safety profile of D-chiro-inositol is much less well-developed, but clinical studies have yet to report toxicities or other dangerous side effects. People are less likely to encounter D-chiro-inositol supplements exclusively; most formulations contain either myo-inositol alone or a combination of the two isomers.
How do you take inositol?
Inositol is currently an over-the-counter dietary supplement that does not require a prescription. But without the help of a medical professional, it can be challenging to determine which products are most likely effective in treating your particular PCOS symptoms.
In research studies and clinical practice, typical inositol dosages for PCOS and metabolic disorders is 2g of active ingredient taken once or twice daily. Studies published so far have assessed patients over a set amount of time, usually in a matter of months, so there is no research-based recommendation regarding the duration of treatment.
Endocrinologists have pointed out that commercially available inositol supplements vary widely in their composition—one paper presents a list of formulas in which the ratio of myo-inositol to D-chiro-inositol ranges from 0.4:1 to 104:1. Based on preliminary studies focused on restoring ovulation, some scientists believe a 40:1 ratio may be the most promising treatment combination. Still, definitive answers will require more clinical studies.
On top of paying attention to isomer ratios, it’s essential to be aware of the presence of additional compounds in any supplement. Many inositol dietary supplements contain added substances such as vitamin C, zinc, and glucomannan. There is little research on how the effects of these active ingredients may change when combined. Some research also supports taking both inositol and folic acid to promote fertility.
The verdict: Should people with PCOS seek out inositol treatment?
Inositol may be a helpful supplement in the treatment of PCOS.
Since formulations of over-the-counter inositol supplements can vary widely, consulting a physician or another expert is worthwhile when selecting a specific treatment. Finally, even in best-case scenarios, PCOS is a highly multifaceted condition with a wide range of symptoms and affected biological systems. Inositol is unlikely to be a magical cure-all that addresses every issue at once. Maintaining optimal metabolic health through diet and lifestyle should always be at the core of your PCOS strategy.
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