Inositol: Benefits, Side Effects, Dosage, and Interactions

Inositol is a type of sugar that influences both the body's insulin response and several hormones associated with mood and cognition. It's often referred to as vitamin B8, but it is not actually a vitamin.

Inositol is found naturally in cantaloupe, citrus fruit, and many fiber-rich foods (such as beans, brown rice, corn, sesame seeds, and wheat bran). It is also sold in supplement form and used as a complementary therapy to treat a wide range of medical conditions, including metabolic and mood disorders.

D-chiro-inositol, inositol hexaphosphate (often referred to as "IP6"), and the compound myo-inositol are the most widely used inositol supplements. They are generally considered safe if taken appropriately.

This article discusses the potential health benefits and uses of inositol. It also covers dosage, preparation, potential side effects, and interactions you should consider before taking this substance.

Potential Health Benefits of Inositol

Inositol plays an important part in cell growth and functioning. Some research has found that inositol may have a number of health benefits, including:

• Lowering the risk of metabolic syndrome, which is a risk factor for a number of conditions including increased belly fat, high blood pressure, and high blood sugar
• Lowering high cholesterol
• Helping the body regulate and process insulin
• Helping relieve anxiety and symptoms of panic disorder
• Reducing the risk of gestational diabetes
• Relieving symptoms of depression
• Relieving symptoms of polycystic ovary syndrome (PCOS)
  

Uses for Inositol

What is inositol used for? Alternative health providers recommend inositol supplements for a wide range of health conditions, including mood disorders, anxiety, ADHD, and PTSD.

However, it is important to use caution when evaluating such claims. While there may be some evidence that inositol might benefit certain conditions, more research is needed. Inositol should not be used as a monotherapy or in place of traditional treatments for these conditions.

There is some research that inositol may benefit some disorders, including mental health concerns, PCOS, and metabolic disorders. Here's a closer look at the science behind the different uses of inositol.

Mental Health Disorders

How inositol affects mental health conditions is not clear. Some research indicates that inositol might play a part in the development of certain mental health conditions, although the exact mechanisms are not clear and more research is needed. It has been suggested that inositol might influence depression, anxiety, and other mental disorders by impacting "feel-good" hormones serotonin and dopamine.

A number of studies have investigated the use of inositol as an add-on treatment alongside selective serotonin reuptake inhibitors (SSRIs), which are used to treat a variety of depressive and anxiety disorders. However, results have not demonstrated an antidepressant effect.

Depression

Inositol may have some positive effects for depression, but it is important to note that the evidence remains inconclusive. One study found that myo-inositol concentration in blood might be a reliable marker for clinical depression.

While an earlier double-blind study found that a daily 12-gram dose of inositol improved depression scores compared to people provided a placebo, the results have not been replicated elsewhere.

Panic Disorder

The compound has also been investigated for its potential impact on anxiety conditions. The benefits have mostly been seen in people with panic disorder in whom depression is common. A small study published in the Journal of Clinical Psychopharmacology investigated the effect of myo-inositol on 20 people with panic disorder.

After being provided a daily 18-gram dose of myo-inositol for four weeks, the participants were given a daily 150-mg dose of Luvox (fluvoxamine)—a commonly prescribed psychiatric drug—for the four weeks. Compared to a matched set of individuals not given myo-inositol, those who were given myo-inositol had an average of 2.4 fewer panic attacks per week.

However, more research is needed to better understand the impact inositol might have on anxiety disorders.

Bipolar Disorder

While research is limited, some studies suggest that inositol might have the potential to reduce symptoms of bipolar disorder. In one study, children affected by bipolar conditions experienced fewer symptoms of depression and mania after taking inositol and omega-3 fatty acids for 12 weeks.

The compound has also been found to reduce psoriasis symptoms in people taking lithium, a drug commonly prescribed to treat bipolar disorder, depression, schizophrenia, and eating disorders. Depending on the usage, lithium-induced psoriasis can affect anywhere from 3% to 45% of people who take lithium.

Metabolic Disorders

There is evidence to suggest inositol has benefits for metabolic disorders that contribute to the development of high blood pressure, diabetes, and metabolic syndrome.

A 2016 pilot study published in the International Journal of Endocrinology reported that people with type 2 diabetes given myo-inositol and d-chiro-inositol daily along with their anti-diabetes drugs had a significant drop in their fasting blood glucose (192.6 mg/dL down to 160.9 mg/dL) and A1C (8.6% down to 7.7%) after three months.

Another small study published in the journal Menopause suggested that myo-inositol may aid in the treatment of metabolic syndrome in postmenopausal women. According to the research, women assigned to six months of myo-inositol supplements experienced significantly greater improvements in blood pressure and cholesterol levels than women provided a placebo.

All of these values translate to an improvement of metabolic syndrome as well as a decreased risk of cardiovascular disease.

Polycystic Ovary Syndrome (PCOS)

D-chiro-inositol may help manage PCOS, according to a small study published in Endocrine Practice. For this study, 20 women with PCOS were given either a placebo or 6 grams of D-chiro-inositol once daily for six to eight weeks.

The results revealed that D-chiro-inositol helped treat several abnormalities associated with PCOS, including high blood pressure and elevated levels of blood fats. In addition, elevated testosterone levels (consistent with PCOS-related hormone imbalances) decreased by 73% compared to 0% for those given a placebo.

Generally speaking, normalization of hormonal balances translates to an improvement of PCOS symptoms.

Possible Side Effects of Inositol

Are there any dangers associated with taking inositol? Inositol is generally considered safe in adults. Side effects, if any, tend to be mild and may include nausea, stomach pain, tiredness, headache, and dizziness. Most side effects occur with doses greater than 12 grams per day.

Although there are some studies to suggest inositol may be helpful in bipolar disease, there is also concern about it possibly causing a manic or hypomanic episode.

There is also some concern that high doses of inositol hexaphosphate may reduce the body's ability to absorb zinc, calcium, iron, and other essential minerals, triggering nutritional deficiencies even if you're eating a balanced diet.

As dietary supplements, inositol products are not tested for safety, and their effect on pregnant people, nursing people, and children has not been established.

Dosage and Preparation

Inositol supplements are sold as tablets and capsules. There is no recommended daily allowance for inositol and there is no standardized dosing schedule.

Manufacturers recommend the following doses for supporting individual conditions:

• Metabolic syndrome: 2 grams twice daily
• PCOS: 2 grams twice daily
• Lithium-related psoriasis: Up to 6 grams once daily
• Anxiety and panic attacks: Up to 12 grams daily

What to Look For

Widely available for purchase online, inositol supplements can also be found in natural foods stores and stores specializing in dietary supplements. To ensure quality and safety, always look for products tested and approved by an independent certifying body like the U.S. Pharmacopeia (USP), NSF International, or ConsumerLab.

If you decide to take an inositol supplement, speak with your doctor to ensure that it's appropriate based on your health and medical history.