Taking inositol regularly may reduce the frequency of panic attacks.[1] In one small randomized controlled trial (RCT) in people with panic disorder, taking 12 grams per day of inositol for a month was more effective at reducing the frequency of panic attacks than a placebo.[2] And in another small RCT, taking 18 grams per day of inositol for a month was as effective as a month of daily fluvoxamine (an antidepressant) at reducing the frequency of panic attacks, although antidepressants like fluvoxamine usually take a minimum of 4 weeks to begin working.[3] Inositol appears to be a promising supplement for panic disorder, although more research is needed.[4]
However, if a panic attack is already in progress, taking a dose of inositol may not have any effect on the panic attack: A 1997 study in seven people with panic disorder found that a single 20-gram dose of inositol had no effect on a chemically-induced panic attack.[5]