Inositol
What is it?
Inositol is a constituent of phospholipids in cellular membranes, a precursor of secondary messengers in metabolic pathways, a component of reproductive fluids, and essential for tissue growth. (32)(39) Previously considered an essential B vitamin (vitamin B8), it is now known that the human body can synthesize four grams of inositol per day, whereas approximately one gram per day can be obtained from the diet. (14) For this reason, inositol is now mainly referred to as an essential pseudovitamin. (24)
Not be confused with: D-pinitol (structurally related)
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Formulations
Dosing & administration
Adverse effects
At doses greater than 12 g per day, gastrointestinal effects, such as nausea, flatulence, and diarrhea, may occur. However, the incidence of these events is considered mild and does not increase in severity as the dose increases. (8) Increasing doses (300 to 2400mg) of DCI has been shown to negatively impact oocyte quality in patients with PCOS. (25)
Pharmacokinetics
Absorption
Distribution
- SMIT1/SMIT2 and the H+ myo-inositol transporter are responsible for inositol uptake throughout the body and brain. (14)
- Myoinositol can pass the blood-brain barrier for distribution to the brain and cerebrospinal fluid in rats. (36)(37)
- Myoinositol is also distributed to seminal fluids, prostate, epididymis, and seminal vesicles, and is high in follicular fluid of healthy Px, but low in PCOS Px. (4)
- D-chiro-inositol is highly distributed to fat, muscle, and the liver, but is low in the brain and heart in humans. (31)
- D-chiro-inositol is high in follicular fluid of PCOS Px, but low in healthy Px. (4)