Nutritionist quick-fire – your CoQ10 top questions, smashed

CoQ10 has become a hot topic in the fertility world for its powerful role in boosting sperm and egg quality (catch our nutritionist’s CoQ10 cheat sheet for fast tips on how to rocket fuel). But with all the buzz, it’s easy to get overwhelmed by questions about dosage, timing, and its benefits. 

In today’s quick-fire, we’re catching up with Head of Nutrition at Zita West Products Rebecca Traylen, tackling your top questions and covering everything from optimum dosage and when to stop taking CoQ10 for fertility (and when to start), to which form is best.

Plus, that all-important ubiquinol vs ubiquinone question. 

Fast-acting and bioavailable, my go-to premium CoQ10 for fertility (shop it here) currently has 10% off at Zita West Products with code TRB10* (site-wide, UK and US) – just pop it in the box at checkout.

1. What sort of dosage is ideal for fertility? 

First things first, it’s important to make the distinction between male and female fertility here – CoQ10 can support both, so let’s get specific!

Male fertility

Studies suggest a daily dose of 150 mg to 200 mg of ubiquinol (the reduced and active form of CoQ10) can significantly improve sperm count, motility, and overall sperm parameters. For example, in a 2015 study, 60 men with low sperm count who took 150 mg of ubiquinol daily for six months saw a 53% increase in total sperm count and a 26% increase in motility.

While we’re on the topic, do read up in our jam-packed library – we recently published a feature on CoQ10’s impact on sperm motility and morphology which might be helpful. 

Female fertility

In women, CoQ10 (particularly in its ubiquinol form) has been shown to improve ovarian function and fertility, especially for those undergoing IVF. 

A 150 mg CoQ10 dose taken daily for four months showed positive effects on ovarian function and hormonal balance. And, another study focusing on women undergoing IVF reported that 100mg CoQ10 (plus 600 mg omega-3) taken for two months before ovarian stimulation significantly increased the clinical pregnancy rate. 

With this in mind, at Zita West we generally recommend 200 mg per day for those undergoing IVF or with low AMH (anti-müllerian hormone). For women who want to improve their egg quality but have no underlying factors which might be impacting their fertility, 100 mg can be beneficial.

2. When should we start/stop taking CoQ10 for fertility?

Again, it helps to be specific. 

For natural conception

As a guideline, start taking CoQ10 at least three months before trying to conceive (TTC). CoQ10 supports mitochondrial function, antioxidant defence and egg quality, so it makes sense to start supplementing well in advance, to maximise its impact. 

For men, sperm production cycles take about two to three months, so starting CoQ10 supplementation three months before trying for a baby is ideal.

Once pregnant, CoQ10 should be stopped. Whilst there are no studies suggesting it’s harmful, we’re yet to see any studies demonstrating its safety and benefit. 

For assisted conception (IVF, IUI, etc)

If you’re undergoing assisted reproductive techniques like IVF, taking CoQ10 three months before ovarian stimulation or fertility treatment is recommended. At transfer, CoQ10 can be stopped.

3. Who might benefit from CoQ10 for fertility?

Okay, so let’s run through the different groups and situations. 

Age 40+ 

CoQ10 production naturally decreases with age, so individuals over 40 may benefit from supplementation to support egg and sperm quality, mitochondrial function, and overall energy levels.

Men with low sperm count or motility

CoQ10 is particularly beneficial for men experiencing fertility issues like low sperm count, motility or poor sperm morphology. Studies have shown its ability to improve these parameters – take a look at our male factor CoQ10 focus for more in-depth information.

Women with ovarian ageing or fertility concerns

Women experiencing ovarian ageing, diminished ovarian reserve (DOR), or those undergoing fertility treatments like IVF may benefit from CoQ10, due to its positive impact on mitochondrial function, egg quality and endometrial thickness. 

Oxidative stress concerns

People with conditions related to oxidative stress – such as polycystic ovary syndrome (PCOS) or endometriosis – may find supplementation with CoQ10 particularly helpful while preparing to conceive.

4. Can you take too much? 

CoQ10 supplements are generally well-tolerated, and no serious side effects have been reported at standard doses of 100-200 mg/day. However, at very high doses (above 1,200 mg/day), some individuals may experience mild side effects such as:

• Gastrointestinal issues (including nausea, diarrhoea, or loss of appetite)
• Insomnia
• Headaches

If these symptoms occur, reducing the dosage or consulting a healthcare professional is recommended.

If you’re concerned, build your intake up slowly and avoid taking before bed, to reduce any impact on your sleep. 

5. How fast can we expect it to work?

CoQ10’s clinical effects aren’t immediate and typically take time to show up clinically. Most studies report improvements after eight weeks (two months) of regular supplementation, though maximum benefits – especially for fertility – may take three to six months due to the longer cycles of sperm and egg production.

6. Which form/type is best?

Ubiquinol (the reduced, active form of CoQ10) is generally considered the most effective form. It doesn’t require conversion in the body, has faster effects, and is three to five times more bioavailable than ubiquinone (the oxidised form). 

Ubiquinol is usually recommended at lower doses for those seeking faster absorption and greater efficacy. When a higher dose (e.g 600mg) is recommended, this is generally for the ubiquinone version.

Getting even more specific, Kaneka ubiquinol is a highly absorbable form of CoQ10, derived from the natural, yeast-fermented Kaneka Q10™, which is bio-identical to the CoQ10 produced by the body. It’s proven to help restore CoQ10 levels more quickly, and has undergone over a decade of scientific testing to confirm its effectiveness.

Looking for the Zita West discount code? Get 10% off the entire Zita West supplement range (US and UK), with code TRB10* at checkout.

*TRB10 is valid once per customer only. Excludes subscription purchase. This offer cannot be used in conjunction with any other offer. Zita West terms of the site apply.