Inositol (Myo / D-Chiro)
A quasi-B-vitamin that acts as a second messenger for insulin and serotonin signalling. Most evidence-backed natural intervention for PCOS, and a sleeper for anxiety.
Strong for PCOS — multiple RCTs show improvements in ovulation, menstrual regularity, insulin sensitivity, and androgen levels comparable to metformin without the side effects. Strong for panic disorder (12–18 g/day comparable to fluvoxamine in trials). Moderate for OCD and depression. Effects: 8–12 weeks for PCOS markers; 2–6 weeks for mood / anxiety.
Inositol (technically myo-inositol, the most common of nine isomers) is a sugar alcohol that the body uses as a signalling molecule downstream of multiple hormones — most notably insulin, FSH, and TSH. It modulates serotonin receptor sensitivity and has anxiolytic properties. The 40:1 myo-inositol-to-D-chiro-inositol ratio matches what's in healthy ovaries and is the most-studied protocol for PCOS — improving menstrual regularity, ovulation, insulin sensitivity, and androgen levels. Separately, high-dose myo-inositol alone has shown RCT-grade benefit for panic disorder, OCD, and depression. It's safe, well-tolerated, and disarmingly powerful for a 'just a sugar.'
- Form
- Myo-inositol — the standard form, mildly sweet powder, mixes in water. 40:1 myo + D-chiro blend for PCOS (the Ovasitol formulation is the most-studied). Avoid 'inositol hexaphosphate (IP6)' for these uses — different mechanism, different effects.
- Dose
- PCOS: 2 g myo + 50 mg D-chiro twice daily (4 g + 100 mg total). Anxiety / OCD / depression: 12–18 g/day myo-inositol divided into 2–3 doses. General use / sleep: 2–4 g pre-bed.
- Timing
- With food. AM and PM for PCOS dose. Pre-bed for sleep / calm.
- Schedule
- Daily.
- Side effects
- Generally well-tolerated. GI upset, gas, mild loose stools at high doses (>10 g). Dizziness or fatigue in some at therapeutic doses.
- Interactions
- Lithium — inositol may reduce lithium's mood-stabilising effect (mechanism: lithium works partly by depleting inositol). Diabetes medications — additive glucose lowering. Hormonal contraceptives — interaction debated.
- Contraindications
- On lithium for bipolar disorder (without psychiatrist input). Bipolar disorder generally (theoretical mania risk at very high doses).
- Lab markers
- Fasting insulin, HbA1c, and androgen panel (testosterone, DHEAS, free androgen index) for PCOS tracking. Hamilton Anxiety / Y-BOCS for mood/anxiety conditions.
- Food sources
- Fruits (cantaloupe, oranges, strawberries), beans, brown rice, oats, nuts. Total dietary intake is typically 0.5–1 g/day — supplementation delivers far more.
Pairs with
Folate (methylfolate) + vitamin D in PCOS protocols. Magnesium glycinate + L-theanine for anxiety / sleep stack. Berberine, alpha-lipoic acid for additional insulin sensitisation.
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