When you are trying to conceive, it feels like absolutely every decision matters - tracking your cycle, identifying ovulation, researching diets and supplements that support reproductive health - there is an overwhelming amount of information to navigate. Amongst that information, you have probably gleaned that inositol has become widely talked-about, particularly for women with PCOS.

But can inositol actually improve fertility, or is the research more complicated than the online conversation suggests? Let’s take a look at where inositol may fit, what it could potentially support and what it cannot guarantee.

Firstly, let's look at how ovulation connects to fertility.

Ovulation occurs when an ovary releases an egg, typically once during a menstrual cycle. For pregnancy to occur naturally, an egg needs to be released, fertilised and successfully implanted in the uterus. If ovulation happens irregularly or not at all, it can become more difficult to conceive because your fertile windows are unclear.

While it it not the only cause, PCOS is one of the most common causes of irregular ovulation. Women with PCOS may experience:

↳ Longer or unpredictable menstrual cycles
↳ Infrequent ovulation
↳ Cycles where ovulation does not occur
↳ Difficulty identifying their fertile window
↳ Longer periods of trying to conceive

Importantly, having a period does not always confirm that ovulation occurred. Likewise, an irregular cycle does not necessarily mean pregnancy is impossible.

You can learn more about PCOS, insulin signalling and why inositol is being studied in Part 1 of our Inositol Series here →

Why can PCOS affect ovulation?

Ovulation relies on carefully coordinated signals between the brain, hormones and ovaries. Higher androgen levels, insulin resistance, and disrupted ovarian signalling may interfere with normal follicle development and egg release.[1]

Insulin resistance can be particularly relevant. When cells do not respond effectively to insulin, the body may produce more to compensate. Higher insulin levels can influence androgen production within the ovaries, which may disrupt the hormonal signals involved in ovulation.[1]

This is one of the reasons researchers have become interested in inositol.

Where does inositol fit?

Inositol is involved in cellular communication, including pathways connected to insulin and reproductive hormone signalling. By supporting the way cells respond to insulin, inositol may indirectly support some of the processes involved in ovarian function and ovulation.

Research has explored whether inositol may influence:

↳ Menstrual-cycle regularity
↳ Ovulation frequency
↳ Insulin sensitivity
↳ Androgen-related markers
↳ Ovarian response during fertility treatment

Some studies have reported improvements in ovulation or menstrual regularity among women with PCOS. However, the available trials vary in quality and have used different inositol forms, combinations and study methods.[2,3] This makes it difficult to predict how any individual woman will respond.

Can inositol help you ovulate?

There is some evidence suggesting that inositol may support ovulation in certain women with PCOS, particularly where insulin resistance is affecting ovarian function.[2,3]

The proposed connection looks something like this:

↳ Inositol participates in insulin signalling
↳ Improved insulin signalling may reduce the need for the body to produce excess insulin
↳ Lower insulin levels may reduce some of the hormonal disruption affecting the ovaries
↳ More supportive ovarian signalling may help some women ovulate more regularly

To be clear, this does not mean inositol directly triggers ovulation in the way that prescribed ovulation-induction medication can. Instead, the possible benefit appears to come from supporting some of the underlying metabolic and signalling pathways that may be contributing to irregular ovulation.

Does more regular ovulation mean improved fertility?

The best answer research can give at this point is 'potentially', but it's important to separate the different stages involved.

↳ A more regular menstrual cycle does not always confirm ovulation
↳ Ovulation does not guarantee fertilisation
↳ Fertilisation does not guarantee implantation
↳ Pregnancy does not guarantee a live birth

If someone begins ovulating more regularly, they may have more predictable opportunities to conceive. However, fertility is influenced by many factors beyond ovulation, such as:

↳ Age
↳ Egg and sperm health
↳ Fallopian-tube health
↳ The uterus and endometrium
↳ Timing of intercourse or insemination
↳ Other medical or reproductive conditions

The current evidence is not strong enough at this stage to claim that taking inositol will guarantee increased chance of pregnancy for all women trying to conceive.[1,2]

What about egg quality?

You may have seen claims that inositol improves egg quality, particularly in content about IVF and assisted reproductive treatment. Myo-inositol is involved in reproductive-cell signalling and has been studied in women undergoing ovarian stimulation. Some studies have reported differences in measures such as ovarian response, medication requirements or characteristics of collected eggs.

However, “egg quality” is a broad term, and improvements in laboratory or intermediate measures do not automatically result in higher pregnancy. Research in this area is still developing, and inositol should not be promoted as a proven way to improve egg quality or reverse the natural effects of reproductive ageing.[2,4]

Can women without PCOS take inositol for fertility?

Much of the interest around fertility relates to women experiencing irregular ovulation, insulin resistance or other PCOS-related concerns, but inositol is not exclusively used by women with PCOS.

There is currently less evidence supporting routine inositol supplementation as a general fertility aid for every woman trying to conceive. If your cycles are regular and you do not have signs of insulin resistance or ovulatory dysfunction, it ought not be assumed that adding inositol will guarantee increased likelihood of pregnancy.

Is inositol a fertility treatment?

Inositol should not be positioned as a fertility treatment or a replacement for prescribed care. This doesn't mean inositol is irrelevant, but its role is different.

Whereas fertility medications are specifically prescribed and monitored to induce ovulation, inositol may be considered as a nutritional support for some of the metabolic and ovarian pathways associated with PCOS.