If you've spent any time researching supplements for hormonal balance, you've probably run into two words that sound almost identical: myo-inositol and D-chiro-inositol. They're not the same thing, and the ratio between them turns out to matter a lot. Myo D-Chiro Inositol+ pairs the two in a 40:1 ratio — the balance the body keeps naturally, and the one most often used in research on women's hormonal health. Like everything we make, it starts with the same promise: third-party tested, every batch, in an NSF-certified, GMP-certified, FDA-registered U.S. facility, with nothing on the label we can't back up. You can see the full Myo D-Chiro Inositol+ product page for pricing and subscription options.
This one is built for women 30 and up who are paying closer attention to hormonal balance — whether that means a cycle that feels less predictable than it used to, wanting steadier ovarian function support, or simply wanting a daily-foundation supplement built around the same ratio researchers actually study, rather than a round number that's easy to print on a label.
Quality first: how Myo D-Chiro Inositol+ is made
Before we talk about ingredients, we want to talk about how we stand behind them. Every batch of Myo D-Chiro Inositol+ is third-party tested by an outside lab for purity and potency — not just tested once during development, but every single batch that goes out the door. It's made in the USA in a facility that's NSF-certified, GMP-certified, and FDA-registered, which means the manufacturing process itself is independently audited, not just the finished bottle.
We also believe in full label transparency: no proprietary blends hiding the actual milligram amounts, no "and other ingredients" doing the heavy lifting. Both the 1,000 mg of myo-inositol and the 25 mg of D-chiro-inositol are printed on the label individually, not folded into a single unlabeled "inositol blend" the way some lower-cost formulas do it — which matters, because the whole point of the 40:1 ratio is knowing the actual numbers on both sides of it. Myo D-Chiro Inositol+ is vegan, vegetarian, gluten-free, non-GMO, sugar-free, and caffeine-free, formulated with women 30+ in mind. You can read more about how we test and where we manufacture on our standards page.
What is myo-inositol, and what does it do for women over 40?
Inositol is a vitamin-like sugar alcohol your body makes naturally and also gets from food — it's found in cell membranes throughout the body and plays a role in how cells respond to insulin and certain hormone signals. There are several forms, but two matter most for women's hormonal health: myo-inositol and D-chiro-inositol. Your body converts myo-inositol into D-chiro-inositol as needed, and in healthy tissue that conversion tends to land in roughly a 40-to-1 ratio — a lot of myo-inositol, a small amount of D-chiro-inositol.
That's the ratio most inositol research on women's hormonal health has used, and it's why Myo D-Chiro Inositol+ is built to match it: 1,000 mg of myo-inositol paired with 25 mg of D-chiro-inositol (as Caronositol®, a branded D-chiro-inositol sourced from carob) in every two-capsule serving.* Together, myo-inositol and D-chiro-inositol support hormonal balance and reproductive health in women, support healthy ovarian function, and help support healthy glucose metabolism and metabolic wellness.*
What does the research say?
Inositol research has grown quickly over the past decade, and most of it centers on the 40:1 myo-inositol to D-chiro-inositol ratio specifically. A 2019 study published in a peer-reviewed OB/GYN journal found that this 40:1 plasma ratio was associated with restored ovulation in women being studied for hormonal and metabolic concerns, and performed differently than other ratios tested (PubMed). A more recent systematic review and meta-analysis, used to help inform the 2023 update of the international evidence-based guidelines on polycystic ovary syndrome, looked across multiple inositol trials and found generally favorable results on hormonal and metabolic markers, while also noting that study quality and dosing vary a lot from trial to trial (Journal of Clinical Endocrinology & Metabolism). A separate review in the National Library of Medicine's PMC archive summarizes myo-inositol's studied role in insulin sensitivity and metabolic health more broadly (PMC).
It's worth being upfront about something here: most of the clinical research on the 40:1 ratio has been conducted in women who were also being evaluated for polycystic ovary syndrome (PCOS), because that's where researchers first noticed the ratio mattered. Myo D-Chiro Inositol+ is a dietary supplement, not a treatment for PCOS or any other diagnosed condition — it's formulated to support hormonal balance, reproductive health, and healthy ovarian function generally.* If you have PCOS or another diagnosed hormonal condition, talk with your doctor about whether inositol supplementation makes sense as part of your overall care.
Beyond hormonal balance specifically, myo-inositol has also been studied more broadly for its role in how the body responds to insulin, which is part of why it's often discussed alongside metabolic wellness, not just reproductive health. The PMC review linked above walks through this connection in more detail if you want to go deeper on the mechanism. As with most dietary supplements, study designs, doses, and the populations studied vary from trial to trial — we think it's more useful to link you to the actual research than to oversell what any one study found.
What's inside Myo D-Chiro Inositol+ (per serving)
Every fact below comes straight off our own label — nothing here is estimated or rounded up.
- Myo-Inositol — 1,000 mg
- D-Chiro Inositol (Caronositol®) — 25 mg
- Other ingredients: Hypromellose (vegetable capsule), microcrystalline cellulose
- Count: 60 capsules — a 30-day supply at the directed dose
- Serving size: 2 capsules, once daily
How and when to take it
As a dietary supplement, take two capsules once a day. For best results, take them 20 to 30 minutes before a meal, or as directed by your healthcare professional. Because it's caffeine-free, there's no reason it has to be a morning-only supplement — some women prefer taking it before dinner instead. The main thing is consistency: inositol is something your body responds to over weeks, not hours, so it works best as a steady daily habit rather than an occasional one.
Safety, side effects, and who should talk to a doctor first
Do not exceed the recommended dose. Pregnant or nursing mothers, children under the age of 18, and individuals with a known medical condition should consult a physician before using this or any dietary supplement. Keep out of reach of children. Do not use if the safety seal is damaged or missing. Store in a cool, dry place. If you're currently taking medication for a hormonal or metabolic condition, or you have a diagnosed condition like PCOS, talk with your doctor before adding any new supplement to your routine — inositol can interact with how your body manages blood sugar.
Myo D-Chiro Inositol+ FAQs
Is myo-inositol the same thing as D-chiro-inositol?
No. They're related compounds your body interconverts, but they aren't interchangeable, and research suggests the ratio between them — not just the total amount — is what matters for hormonal health.*
Why a 40:1 ratio specifically?
That's the ratio most commonly found in healthy tissue and the one used in most of the clinical research on inositol and women's hormonal health, which is why Myo D-Chiro Inositol+ is formulated to match it.*
Is this a treatment for PCOS?
No. Myo D-Chiro Inositol+ is a dietary supplement formulated to support hormonal balance, reproductive health, and healthy ovarian function generally.* It is not intended to diagnose, treat, cure, or prevent any disease, including PCOS. Talk with your doctor about any diagnosed condition.
Can I take Myo D-Chiro Inositol+ with my multivitamin or other supplements?
Generally yes, but because inositol can affect glucose metabolism, it's worth mentioning to your doctor or pharmacist if you're on medication for blood sugar or hormonal conditions, so they can flag any interactions specific to you.
How long until I notice anything?
Hormonal support supplements are a slow build, not a quick fix — most women take inositol consistently for at least a full cycle or two before evaluating how it fits their routine. Individual results vary.
Does Myo D-Chiro Inositol+ contain caffeine or stimulants?
No. It's caffeine-free, so it won't affect sleep or stack with your coffee, and there's no reason it has to be taken at a specific time of day beyond the 20-30 minutes before a meal suggestion.
How Myo D-Chiro Inositol+ fits a daily routine
Because it's caffeine-free and taken just once a day, Myo D-Chiro Inositol+ slots in easily next to whatever else is already part of your morning or evening — a glass of water at breakfast, or a few minutes before you start prepping dinner.
Hormonal balance rarely lives in isolation — sleep, stress, and midlife hormonal shifts all interact with each other, and a lot of the women who reach for Myo D-Chiro Inositol+ are already paying attention to one or more of those. It pairs easily as a daily-foundation add-on rather than a replacement for anything else in your routine; there's no reason it can't sit next to a multivitamin or a magnesium supplement in the same daily glass of water.
If you're navigating perimenopause or menopause alongside hormonal balance more broadly, our guide to Menopause+ covers a different stage of the same conversation, and our piece on black cohosh, red clover, and dong quai looks at some of the other botanicals commonly researched for women's hormonal health.
Sources
- The 40:1 myo-inositol/D-chiro-inositol plasma ratio is able to restore ovulation — PubMed
- Inositol for Polycystic Ovary Syndrome: A Systematic Review and Meta-analysis — Journal of Clinical Endocrinology & Metabolism
- Myo-inositol for insulin resistance, metabolic syndrome, PCOS, and gestational diabetes — PMC, National Library of Medicine
- Inositol — Dietary Supplement Label Database, NIH Office of Dietary Supplements
Individual results vary.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
