Myo-Inositol Powder for Fertility — Theralogix Ovasitol 40:1 Packets

Description

This myo-inositol powder for fertility from Theralogix delivers 2,000 mg of myo-inositol and 50 mg of D-chiro-inositol per packet, in the 40:1 ratio your body maintains naturally. The directions are two packets daily, which puts you at 4,000 mg of myo-inositol and 100 mg of D-chiro. One box holds 180 packets, a 90-day supply. It is unflavored, dissolves in any non-carbonated drink hot or cold, and contains nothing but inositol.

Format is what makes that possible. Most of the clinical research on myo-inositol used 4 grams daily, split into two doses, and 4 grams is far more than capsules can realistically carry, which is why blended capsule formulas deliver a fraction of it. Powder is the only format that can hold a studied dose. So the fair question for any inositol product is a simple one: how close does it get?

This one doesn't get close. It matches. Two packets a day is the trial protocol, dose and schedule both. That is unusual enough to be worth stating plainly, because most products in this category quietly deliver half and let the research on the box do the talking.

What the ingredient does is better established than most supplement claims. Myo-inositol is a sugar alcohol involved in insulin signaling. In women with PCOS, randomized trials have found it improves menstrual regularity, ovulation rates and androgen levels. The 2024 systematic review and meta-analysis in the Journal of Clinical Endocrinology & Metabolism that informed the 2023 International Evidence-based PCOS Guidelines is the current reference, and it concluded the evidence remains limited. Useful, worth trying, not settled. A correct dose does not change that; it just means you are testing the thing that was tested.

The certification is the second reason this one is different. Ovasitol is NSF contents certified, meaning an independent laboratory verified that what the panel claims is what is in the packet. In a category with no pre-market approval, where a supplement's label is essentially a promise, third-party verification is not a marketing badge. It is the difference between a number and a checked number.

The ingredient list is one line long. Myo-inositol, D-chiro-inositol, nothing else — no fillers, no flavoring, no sweetener, no carrier. That matters more than it sounds like it should, because inositol is taken daily for months and every additive is one you are also taking daily for months.

What is not in here is the thing to plan around. There is no folate, no B12, no iron, iodine, choline, DHA or vitamin D. This is a single-purpose product. Your prenatal has to carry the preconception nutrition, and ACOG's 400 mcg of folate before conception needs to come from somewhere else. If you were choosing between this and a formula that bundles inositol with folate, you are choosing between a full inositol dose and a convenient one.

Ninety days is also not an arbitrary box size. Eggs mature over roughly a 90-day window, and cycle changes from inositol generally take two to three cycles to show. One box is about the shortest honest trial you can run.

Why women love it

• 4,000 mg myo-inositol daily: the dose used in the research, not a fraction of it
• The 40:1 ratio: 2,000 mg myo to 50 mg D-chiro per packet, matching the body's own ratio
• Split dosing, as studied: two packets a day mirrors the morning-and-evening schedule the trials used
• NSF contents certified: an independent lab verified the panel, which almost nothing in this category can say
• Nothing else in it: two actives, no fillers, flavoring or sweeteners
• Unflavored powder: dissolves into water, tea or a smoothie, hot or cold
• 90 days per box: matches the roughly 90-day egg maturation window

Best for

• Women with PCOS or irregular cycles who want the dose the trials actually used
• Anyone who has tried a capsule blend and wants to know they are taking a real amount
• People who want third-party verification rather than a label claim
• Those already on a complete prenatal who need inositol and nothing else
• Not a prenatal. No folate, B12, iron, iodine, choline, DHA or vitamin D
• Two servings a day. If a once-daily routine is what you will stick to, this is not it
• A real cost. About $1.14 a day, though per gram of inositol that is close to the cheapest powders

Related reading

If you landed here because of PCOS, Mindy's guide to how PCOS affects fertility covers what's actually happening with ovulation and where supplements sit among the options. Her guide to preparing your body for pregnancy walks through the three months before trying, and what actually matters in a prenatal explains why this is a different category of product and why you need both.

Explore more

This powder sits in our egg quality supplements collection, curated by Mindy Motta, FNP-C, alongside CoQ10 and preconception formulas. Because it contains inositol and nothing else, it is designed to sit next to a prenatal rather than replace one. The wider fertility essentials for TTC collection adds ovulation tracking and IVF support. If you'd rather have inositol inside a multi-ingredient capsule formula and accept a smaller dose for the convenience, the Eu Natural conception supplement takes that approach, with the trade-offs described on its page.

A quiet companion for the wait

Stirring a packet into a glass twice a day gives the waiting a shape. It doesn't shorten it. Our fertility affirmation candles were made for the part of this that no routine fixes.

A note from Mindy on reading the panel

I want to use this product to make a point that will save you money across every supplement you ever buy. Read the supplement facts panel, not the front of the box. The panel is the document that has to be accurate. And read the real one: product listings on resale sites are frequently out of date or simply wrong, sometimes describing a formulation the company stopped making years ago.

On this panel, three things stand out.

First, the dose is the studied one. Two packets gives you 4,000 mg of myo-inositol and 100 mg of D-chiro, split morning and evening, which is the protocol from the PCOS trials rather than an approximation of it. I spend a lot of time telling people that the product in their hand contains half of what they read about. This is the rare page where I don't have to.

Second, the ratio is deliberate. 40:1 myo to D-chiro is the ratio found in healthy ovarian follicular fluid, and it is the ratio the research used. Products that use more D-chiro are not giving you a stronger version of the same thing.

Third, and this is the one I would flag hardest: there is no folate in here. None. That's a coherent design choice for a single-ingredient product, and I prefer it to a half-dose of everything, but it means your prenatal is doing all of that work. If you are taking this instead of a prenatal rather than alongside one, you have a folate gap, and folate before conception is the single most evidence-backed supplement decision in this entire category. Bring both to your appointment.

Two practical notes. Inositol at 4 grams can loosen stools, so start with one packet daily for the first week and add the second, rather than beginning at the full dose. And give it three months before judging it. Cycle changes typically take two to three cycles to appear, and egg maturation runs on roughly a 90-day window, which is why the box is 90 days.

On the price: it is more than most inositol on the shelf, and I want to be straight about why. Per gram of inositol it costs about the same as the cheap powders. You are paying for twice the dose and for a third-party check that the dose is real. Whether that check is worth the difference is a fair thing to decide for yourself.

— Mindy Motta, FNP-C

FAQs

How much myo-inositol is in Ovasitol?

2,000 mg of myo-inositol and 50 mg of D-chiro-inositol per 2.22 g packet. The directions are two packets daily, which comes to 4,000 mg of myo-inositol and 100 mg of D-chiro. That is the dose and the split schedule used in most of the PCOS research, rather than a reduced version of it.

Is 4 grams of inositol the right dose?

It's the amount most of the clinical trials used, typically split across morning and evening. Products delivering 2 grams once daily give you half of that, which may still help but isn't the protocol that was studied. If you have been taking a capsule blend and wondering whether you're taking enough, this is the comparison to make.

What does the 40:1 ratio mean?

It's the ratio of myo-inositol to D-chiro-inositol, and 40:1 is what's found in healthy ovarian follicular fluid. The research used this ratio deliberately. More D-chiro isn't a stronger formula, it's a different one, and the trials that shaped current practice used 40:1.

Does Ovasitol contain folate?

No. It contains myo-inositol and D-chiro-inositol and nothing else — no folate, no B12, no fillers or flavoring. That means your prenatal has to carry the preconception nutrition, including the 400 mcg of folate ACOG recommends before conception. Take this alongside a prenatal, not instead of one.

What does NSF contents certified mean?

An independent laboratory verified that the product contains what the label says it contains. Supplements aren't approved before they go on sale, so a panel is essentially a promise from the manufacturer. Third-party certification is the only routine way that promise gets checked, and very few products in this category carry it.

Can I take this if I have PCOS?

Myo-inositol is one of the better-studied supplement options in PCOS, with randomized trials showing improvements in cycle regularity and ovulation, though the 2023 International Evidence-based PCOS Guidelines note the evidence remains limited. This product delivers the dose those trials used. Whether it's right for you is a conversation with your provider, particularly if you're also on metformin.

When should I start, and how long before I know?

Start on day one of your cycle if your cycles are regular, since that makes any change easier to track, and at any time if they're irregular. Plan on at least three months. Eggs mature over roughly a 90-day window and cycle effects from inositol usually take two to three cycles to appear, which is why one box is a 90-day supply.

Will it upset my stomach?

Inositol can cause loose stools, gas or nausea at higher doses, and 4 grams is a higher dose. Start with one packet daily for the first week and add the second rather than beginning at the full amount. If symptoms persist past a couple of weeks at either dose, raise it with your provider.