Although often marketed as “Vitamin B8,” inositol is actually a type of sugar molecule, not a vitamin. Inositol can be made in the body or ingested through the diet. It plays a role in cellular messaging, some neurotransmitter activity, and endocrine function.

Inositol is not an FDA-approved medication, but researchers have studied inositol for diabetes, polycystic ovarian syndrome, cancer, and mood disorders. For example, researchers have found the benefits of inositol for certain anxiety disorders compared to placebo.

Very few studies have researched inositol as a treatment for PMDD symptoms. One study of eleven patients with PMDD found no benefit of inositol compared to placebo when patients were treated for six menstrual cycles (Nemets et al, 2009). Another study found improvement in the severity of depressive symptoms in PMDD patients treated with inositol (Gianfranco et al, 2011).

Overall, larger clinical trials are needed to determine if inositol has a role in reducing PMDD symptoms. There are currently no approved vitamins or supplements for PMDD treatment.

Patients should always discuss individualized treatment plans with their primary healthcare provider and be sure to disclose to their doctor any vitamins or supplements they may be taking.

Jordan C. Barone - IAPMD CAB Affiliate. MD/Ph.D. Candidate (Medical Scientist Training Program)