Inositol

Best for

Reduce excess androgens in PCOS

Likely strong benefit · 550–4000 mg/day for 7–26 weeks · 6 meta-analyses , n=31.3k

30 papers · 4 claims · 76 outcomes scored · 4 positive

Outcomes

What inositol actually does, by outcome

Each row is one outcome with effect size, evidence base, the dose that worked in trials, and time to first effect. Magnitude tiers come from native-unit MCID where available, Cohen's d otherwise.

Outcome Effect size Evidence Dose Weeks Rank

Reduce excess androgens in PCOS Likely strong benefit

Lowers the hormones that cause acne, unwanted hair, and missed periods in PCOS.

7 meta-analyses n=31k 550–4000 mg 7–26 wk #1/3

27493664·28544572·29042448·29178904 +3 more

large

7 meta-analyses n=31k Meta-analyzed I²=97%

550–4000 mg

7–26 wk

#1 /3

Improve ovulation and fertility hormones Likely strong benefit

Strengthens the estrogen and progesterone signals that drive ovulation.

3 meta-analyses n=30k 550 mg 26 wk #2/10

27493664·41235304·41757236

large

3 meta-analyses n=30k Meta-analyzed I²=93%

550 mg

26 wk

#2 /10

Restore ovulation in PCOS Large effect, needs confirmation

Triggers the egg release that PCOS has been stalling.

4 meta-analyses n=729 600–4000 mg 7–10 wk #1/2

28544572·29178904·38163998·41757236

large

4 meta-analyses n=729 Meta-analyzed I²=75%

600–4000 mg

7–10 wk

#1 /2

Improve insulin sensitivity Promising early signal

Your cells respond to insulin again so your pancreas works less hard.

11 meta-analyses n=31k 4–4000 g 8–26 wk

27493664·28544572·29042448·33553394 +7 more

moderate

11 meta-analyses n=31k Meta-analyzed I²=93%

4–4000 g

8–26 wk

—

Outcome	Effect	Evidence	Dose	Weeks	Rank
Reduce excess androgens in PCOS Likely strong benefit	large	7 meta-analyses n=31k Meta-analyzed	550–4000 mg	7–26 wk	#1/3
Improve ovulation and fertility hormones Likely strong benefit	large	3 meta-analyses n=30k Meta-analyzed	550 mg	26 wk	#2/10
Restore ovulation in PCOS Large effect, needs confirmation	large	4 meta-analyses n=729 Meta-analyzed	600–4000 mg	7–10 wk	#1/2
Improve insulin sensitivity Promising early signal	moderate	11 meta-analyses n=31k Meta-analyzed	4–4000 g	8–26 wk	—

Buy well

Recommended Inositol products

Real products that dose Inositol where the research does, in a clean formulation, from brands we've audited. We only list ones we'd stand behind.

Chosen for adequate Inositol dosing vs. the studied range, a clean formulation (grade A–C), and independent brand-quality audits. Not sponsored.

Risk profile

Adverse events and known drug interactions

Safety events

Grade 3 adverse events (various: dyspnea, dizziness, pain, arthralgia, cataracts reported in myo-inositol arm) severe

gastrointestinal side effects (nonspecific) mild

nausea mild

diarrhoea mild

flatulence mild

headache mild

bloating mild

fever mild

Drug interactions

Metformin moderate increases effect

other moderate decreases effect

Co-studied with

Supplements that share evidence with inositol

Vitaminb9 52 shared outcomes · d=0.57
Drug:Metformin 26 shared outcomes · d=0.36
Vitamind 11 shared outcomes · d=0.32
Riboflavin 11 shared outcomes · d=0.32
Vitaminb6 11 shared outcomes · d=0.32
Vitaminb12 11 shared outcomes · d=0.32
Zinc 11 shared outcomes · d=0.32
Lactobacillusrhamnosus 11 shared outcomes · d=0.32
Bifidobacteriumanimalis Species 11 shared outcomes · d=0.32
Fattyacids 11 shared outcomes · d=0.32
Iron 11 shared outcomes · d=0.32
Calcium 11 shared outcomes · d=0.32
Iodine 11 shared outcomes · d=0.32
Carotene 11 shared outcomes · d=0.32
Vitamin Unspecified 11 shared outcomes · d=0.32
Lactalbumin 8 shared outcomes · d=0.50

Sources

Generated August 14, 2026

Inositol

What inositol actually does, by outcome

Recommended Inositol products

Adverse events and known drug interactions

Supplements that share evidence with inositol

More evidence for Inositol

The Sweet Messenger: How Inositol Went From "Vitamin B8" to a Careful Yes

Best Supplements to Lower Blood Pressure in Pregnancy (2026)

Best Supplements for Fatty Liver Disease (NAFLD), Ranked by Evidence

Metabolic health: evidence map across 82 supplements

Vitex (unspecified)

Alpha Lipoic Acid

Inositol

Recommended Inositol products

More evidence for Inositol

NewThe Sweet Messenger: How Inositol Went From "Vitamin B8" to a Careful Yes

NewBest Supplements to Lower Blood Pressure in Pregnancy (2026)

NewBest Supplements for Fatty Liver Disease (NAFLD), Ranked by Evidence

NewMetabolic health: evidence map across 82 supplements

NewVitex (unspecified)

NewAlpha Lipoic Acid

The Sweet Messenger: How Inositol Went From "Vitamin B8" to a Careful Yes

Best Supplements to Lower Blood Pressure in Pregnancy (2026)

Best Supplements for Fatty Liver Disease (NAFLD), Ranked by Evidence

Metabolic health: evidence map across 82 supplements

Vitex (unspecified)

Alpha Lipoic Acid