Inositol benefits and side effects

Inositol: You might not recognize the name, but there’s a good chance you eat it every day. It’s often called Vitamin B8, but it’s not technically a vitamin. Rather, it’s a type of sugar that exists in the human body and also in foods like beans, whole grains, nuts, and citrus fruit. The typical U.S. adult consumes around 1 gram per day, but as a dietary supplement, it boasts a medley of potential health benefits. 

Not only has inositol shown promise in treating polycystic ovarian syndrome (PCOS), regulating blood sugar, and improving fertility for certain people, but it might also have a positive influence on mental health, weight loss, and more. This is the go-to guide for inositol’s various health benefits. 

8 potential inositol health benefits 

Citrus, beans, and whole grains are part of a healthy diet, but here are several reasons someone might consider increasing their intake—or taking an inositol supplement. 

1. It may help control blood sugar

Ask anyone who has diabetes: Blood sugar has a huge influence on day-to-day life, and insulin is essential to maintaining a healthy level. So when muscle, fat, and liver cells can’t effectively respond to insulin—called insulin resistance—it may increase blood sugars way outside the normal range. 

That’s where inositol comes in. Certain research studies have shown its ability to increase insulin sensitivity and balance blood glucose. For example, a study published in 2011 showed that inositol decreased insulin resistance in patients with gestational diabetes, and a meta-analysis published in 2019 corroborated inositol’s glucose-stabilizing effectiveness. People taking it for gestational, Type 1, or Type 2 diabetes should be careful taking it with other diabetes medications since they can lower blood sugar when used together.

2. It may reduce symptoms of polycystic ovarian syndrome (PCOS)

PCOS is a condition that often goes hand-in-hand with insulin resistance. It’s characterized by elevated levels of male sex hormones called androgens, which can cause missed or irregular periods, enlarged ovaries, increased body hair, weight gain, acne, and infertility. Women with PCOS also often have an imbalance of Myo-inositol (MI) and D-chiro-inositol (DCI), which is why inositol therapy can help regulate the menstrual cycle and improve ovarian health. 

One recent study published in Reproductive Health in 2021 showed that administering Myo-inositol can help normalize ovarian function in women with PCOS, while a literature review published in 2019 concluded that MI and DCI delivered in a 40:1 ratio can help level out the condition’s hormone imbalance. Getting the correct dosage is important, though, which requires the insight of a healthcare professional.

Tina Marinaccio, a registered dietician and founder of Health Dynamics, says, “I have had great success using Myo-inositol with my clients with PCOS in controlling blood sugar, weight loss, and increasing fertility. I start them on 2,000 milligrams before a morning meal, and then titrate from there depending upon response and client goals.”

3. It might increase fertility

Note the “might.” Infertility is complicated (and that’s an understatement), with a wide range of causes and treatments, so inositol is far from a one-size-fits-all solution. However, it has shown some promise in the world of reproductive health. In fact, the previously mentioned Reproductive Health study published in 2021 found that Myo-inositol and folic acid improved outcomes for women of reproductive age undergoing in vitro fertilization (IVF). 

“Inositol supplementation plays a critical role in ovulation and healthy egg development, increasing the chances of achieving pregnancy. Women undergoing IVF therapy have more successful outcomes with inositol supplementation,” Marinaccio says. “Besides supporting healthier egg development, inositol improves insulin sensitivity and how the ovaries respond to pituitary hormone gonadotropin.”

However, Marinaccio notes that inositol supplementation research has typically focused on women with PCOS or who are undergoing IVF, so it’s unclear whether it can provide fertility benefits to the general public. 

4. It may improve metabolic syndrome

Metabolic syndrome isn’t a single condition. It means having at least three risk factors that can increase the risk of heart disease, stroke, and diabetes. Those factors include high triglyceride levels, low HDL cholesterol, high blood pressure, high blood sugar levels, and a large waist circumference. 

The use of inositol can’t correct all these issues, but according to Trista Best, a registered dietitian at Balance One Supplements, “it has been associated with improvements in lipid profiles, including reductions in total cholesterol and triglyceride levels.” Additionally, she says, “Inositol may play a role in modulating fat storage and metabolism. Research indicates that it could impact enzymes involved in lipid synthesis, potentially affecting how the body stores and utilizes fats.”

That said, inositol alone can’t solve metabolic disorders. It’s best as part of a comprehensive approach that includes a balanced diet, maintaining a healthy weight, regular exercise, and lifestyle changes.

5. It may regulate cholesterol

Nearly 2 out of every 5 Americans have high cholesterol, according to the Centers for Disease Control and Prevention, and every year it causes 2.6 million deaths worldwide, according to the World Health Organization. That’s why “lower your cholesterol” is a refrain echoed in doctor’s offices across the country. While specialized medications and lifestyle changes can help, so can inositol. 

One systematic review of randomized control trials from 2018 suggested that inositol may lower not just triglycerides, but LDL (aka “bad” cholesterol). It didn’t, however, appear to have any effect on HDL cholesterol (aka “good” cholesterol). However, additional research might be necessary to support this conclusion.

6. It might improve mental health

The brain’s superhighways of neurotransmitters affect many of our emotions—and there’s some scientific evidence that inositol can influence them. “Inositol is involved in the phosphatidylinositol (PI) second messenger system, which plays a crucial role in neurotransmission,” says Best. “This system is linked to the regulation of various neurotransmitters, including serotonin, dopamine, and norepinephrine, which are implicated in mood and anxiety disorders.” 

Even so, Best says inositol isn’t a substitute for comprehensive mental health treatment and that a balanced diet, regular exercise, and mental health support play important roles. Plus, researchers have mixed opinions on whether inositol is truly an effective treatment for mental health conditions, so more data is probably necessary. Still, there’s some evidence it might influence certain disorders. 

Panic disorders

Panic attacks are sudden bursts of intense fear or anxiety that can be so crippling that some people mistake them for heart attacks. For anyone with a panic disorder, these attacks come seemingly out of nowhere and happen frequently. Yet patients who took 18 grams of inositol per day for one month had fewer panic attacks each week during a study published in 2001. Likewise, an earlier small study demonstrated that patients’ panic attacks decreased in frequency and severity after taking inositol. 

Mood disorders

Everyone has moods, but when they hit peaks or valleys and simply don’t return to normal, it could be a mood disorder. The two most prevalent and well-known are depression and bipolar disorder—both of which may respond to inositol. An analysis of randomized, placebo-controlled trials suggested inositol could potentially combat depression, particularly in patients with premenstrual dysphoric disorder. Drugs for bipolar disorder often deplete inositols, so one study concluded that taking an inositol supplement alongside lithium and valproic acid could reduce side effects. 

Obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) manifests as repeated, unwanted thoughts that compel someone to take certain actions—often in ways that interfere with daily activities. In a study published in 1996, patients with OCD taking 18g of Myo-inositol per day had significantly lower scores on the Yale-Brown Obsessive Compulsive Scale than when taking a placebo. 

7. It may accelerate weight loss

When it comes to weight loss, there’s no get-thin-quick scheme. However, when combined with a healthy diet and exercise, inositol has shown some promise. In one recent study of 43 overweight PCOS patients, those who dieted and took Myo-inositol achieved greater weight loss than those who dieted without taking Myo-inositol. Still, everyone’s body is different, so efficacy may vary. 

“Most research on inositol and weight loss centers around people with PCOS,” Marinaccio says. “But inositol supplementation can be used as an adjunct treatment to lifestyle change for weight loss for healthy individuals, and people with diabetes and prediabetes.”

Best agrees that inositol works as a supplemental treatment. “While there is some promising research suggesting that inositol, particularly Myo-inositol, may contribute to improved insulin sensitivity, appetite regulation, and lipid metabolism, it is not a standalone solution for weight management,” says Best. “A comprehensive approach to weight management, encompassing a balanced diet, regular physical activity, and lifestyle modifications remains crucial.”

The bottom line is that the research around inositol as a weight loss treatment is ongoing, and anyone who thinks it might help should consult a healthcare professional first. 

8. It might improve sleep quality

Experts have spilled a lot of ink over the years on the importance of sleep. It’s crucial for physical and mental wellness, but many people still struggle to get a solid night of shut-eye. Inositol might help, although the evidence for its efficacy as a sleep age is largely anecdotal right now. Still, one study from 2017 linked low concentrations of frontal cortex Myo-inositol to poor sleep (and depression) in adolescents, and another study from 2020 connected it to better sleep quality in pregnant women. 

How to take inositol

Most people consume inositol almost every day without even thinking about it. That’s because it’s in some very common foods, including whole grains, beans, brown rice, nuts, citrus, cantaloupe, and other fresh fruits. Simply eating more of these food sources will increase inositol intake, but it might be hard to eat enough of them to hit the levels required for treating certain medical conditions. That’s why people with PCOS, diabetes, mood disorders, or metabolic disorders might want a more concentrated dose. 

Inositol tablets and capsules are available over the counter, but it’s often best to consult a doctor before taking them for two main reasons. The first is that inositol may interact with certain medications, particularly diabetes medicines, since both can decrease blood sugar levels. The second is that there are multiple forms of inositol—each with its own properties—and no official standards for dosing. 

Different conditions may require different doses of inositol. For example, someone with PCOS might need Myo-inositol and D-chiro-inositol at a 40:1 ratio, while someone with gestational diabetes might need 4 g of only Myo-inositol. Plus, it’s often coupled with folic acid, although not always. A healthcare provider can provide professional medical advice on the best type of inositol and dosage for each condition. 

Side effects of eating inositol 

The Food and Drug Administration (FDA) has categorized inositol as “GRAS,” which means “generally regarded as safe.” Taken in small doses, inositol rarely causes adverse effects, but they’re still possible. In one study that administered the supplement at or above 12 g per day, patients reported nausea, diarrhea, gas, headaches, and dizziness. These mild side effects didn’t increase in severity, though, even at 30 g per day. 

There’s very little data on the effects of inositol on nursing mothers, although natural breast milk is rich in Myo-inositol, which may be healthy for the developing brain. 

Bottom line 

Although inositol has an array of research-backed benefits, a lack of major side effects, and over-the-counter availability, inositol isn’t a super drug—but this nutritional supplement can help certain people with healthcare provider approval. Showing positive effects for people with PCOS, metabolic syndrome, and high blood sugar, and promise in fertility and depression, it’s an attractive option. And while it’s present in plenty of foods, just remember: Consult a doctor before taking an inositol supplement (either pill or tablet form), since different conditions require different types and doses.