CoQ10 for Fertility (Male & Female)

Fertility — scientific infographic poster

Sperm and eggs both depend on mitochondria, and CoQ10 is part of the mitochondrial energy chain as well as a membrane antioxidant, which is why it has been studied in fertility. In men with low sperm motility, placebo-controlled trials (Balercia 2009 and others) found that CoQ10 improved sperm measures, but a 2013 meta-analysis of three trials found that CoQ10 did not increase pregnancy rates, and none of the trials reported live births. In women having IVF, a double-blind trial of CoQ10 600 mg/day in women aged 35-43 (Bentov 2014) was stopped early and found no significant differences, and a trial in women under 35 with poor ovarian reserve (Xu 2018) found more eggs and better embryos without a significant difference in pregnancy or live birth. Cochrane reviews of antioxidants as a group rate the evidence for live birth as very low certainty in both men and women, and a large US trial of a multi-antioxidant formula for men (MOXI) found no benefit. This deep-dive covers these studies, the proposed sperm and egg mechanisms, the doses the trials used and what remains untested.


💥 Interactive Visualization Free Radicals & Your Antioxidant Network Follow one superoxide radical down the whole relay — SOD, catalase, glutathione, vitamin E, vitamin C, NADPH — then release free iron and watch a membrane tear itself apart. Launch → 🫄 Interactive Visualization Fertilization — follow the sperm and time the fertile window Watch 200 million sperm thin to a few hundred at the egg, harden the zona against the second one — then miss the window by two days and see nothing happen at all. Launch →

Table of Contents

  1. Why Reproductive Cells Are Uniquely Mitochondria-Dependent
  2. Sperm Mitochondria & Motility
  3. Oocyte Mitochondria & Reproductive Aging
  4. The Balercia Male-Fertility Trials
  5. Meta-Analyses, Cochrane Review and the MOXI Trial
  6. The Bentov & Casper IVF Trial
  7. Xu 2018 — Young Women with Poor Ovarian Reserve
  8. Doses Used in Male-Fertility Trials
  9. Doses Used in Female-Fertility Trials
  10. Combination Therapy (Zinc, Selenium, DHEA, Vitamin D)
  11. Timing Before IVF: What Was Tested
  12. Patient FAQ
  13. Safety and Interactions
  14. Key Research Papers
  15. Connections
  16. Featured Videos

Why Reproductive Cells Are Uniquely Mitochondria-Dependent

Sperm and eggs (oocytes) both depend on mitochondria, but in different ways. CoQ10 is part of the mitochondrial electron transport chain, carrying electrons from Complexes I and II to Complex III, and it also acts as a fat-soluble antioxidant in cell membranes. That dual role is the reason it has been studied in fertility.

Sperm

A mature sperm cell has three working parts: the head, which carries the father's chromosomes and the acrosome (the enzyme cap used to penetrate the egg's outer coat); the midpiece, where the sperm's mitochondria are wrapped around the base of the tail; and the tail (flagellum), which drives swimming. The midpiece mitochondria supply energy for the tail's movement, and they also produce reactive oxygen species (ROS) as a by-product. Sperm membranes are rich in polyunsaturated fats that oxidize easily, so membrane antioxidants such as ubiquinol (the reduced form of CoQ10) have been proposed as protective.

In the placebo-controlled trial by Balercia and colleagues (2009), described below, men with lower starting sperm motility and lower seminal CoQ10 levels were more likely to respond to CoQ10.

Oocytes

The egg is one of the largest cells in the body and carries a very large population of mitochondria. After fertilization the embryo keeps only the mother's mitochondria, because the sperm's mitochondria are not passed on, so the egg's mitochondria have to power the first cell divisions.

Eggs are formed before a woman is born and stay arrested part-way through meiosis for decades until ovulation. The age-related decline in egg quality has several proposed causes. In a study of eggs from naturally cycling women, abnormal meiotic spindles with misplaced chromosomes were seen in 79% of eggs from women aged 40-45, against 17% of eggs from women aged 20-25 showing aneuploid conditions (Battaglia 1996). Bentov and colleagues (2014) note that most age-related aneuploidy arises at the second meiotic division and is attributed mostly to dysfunction of the cohesin and shugoshin proteins that hold chromosomes together; reduced mitochondrial function is a further proposed contributor.

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Sperm Mitochondria & Motility

Asthenozoospermia means reduced sperm motility on a semen analysis, judged against World Health Organization reference limits. “Idiopathic” means no anatomical, hormonal or infectious cause was found. Oxidative stress is one proposed cause; a 2022 Cochrane review notes estimates that 25% to 87% of male subfertility is considered to be due to the effect of oxidative stress (de Ligny 2022).

Sperm function depends on:

CoQ10 is proposed to act on the first three through its roles in ATP production and as a membrane antioxidant. In the trials cited on this page, CoQ10 by mouth raised CoQ10 levels in seminal plasma and in sperm cells (Balercia 2004; Balercia 2009), and lowered a blood marker of lipid peroxidation while raising the total antioxidant capacity of seminal plasma (Nadjarzadeh 2011). Whether these changes lead to more pregnancies is the open question covered in the sections below.

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Oocyte Mitochondria & Reproductive Aging

The fall in fertility with a woman's age is steep. Bentov and colleagues (2014) quote a US national report for 2005 in which the live-birth rate after IVF with fresh embryo transfer fell from 43% in women under 35 to 6% in women over 42. Because donor eggs from younger women do not show the same age-related decline, the egg itself is considered the main target of reproductive aging.

Evidence linking egg mitochondria to egg quality:

A review by Bentov and Casper (2013) sets out the case for mitochondrial dysfunction and oxygen radicals in reproductive aging and discusses CoQ10 deficiency as a possible contributor. This line of reasoning, built largely on animal work, is why CoQ10 has been tested in women having IVF.

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The Balercia Male-Fertility Trials

Giancarlo Balercia and colleagues in Ancona, Italy, published two of the first clinical studies of CoQ10 in men with idiopathic asthenozoospermia.

Balercia 2004 (Fertility and Sterility)

Balercia 2009 (Fertility and Sterility)

A placebo-controlled, double-blind randomized trial:

Results reported in the abstract:

Other trials in men

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Meta-Analyses, Cochrane Review and the MOXI Trial

Lafuente 2013 meta-analysis (Journal of Assisted Reproduction and Genetics)

This meta-analysis pooled three trials of CoQ10 by mouth: 149 men on CoQ10 and 147 on placebo.

The authors concluded that there is no evidence that CoQ10 increases either live birth or pregnancy rates, although sperm parameters improved overall, and that adequately powered trials are needed.

Cochrane review: antioxidants for male subfertility (de Ligny 2022)

The 2022 update of this Cochrane review included 90 studies with 10,303 subfertile men and 20 different oral antioxidants, CoQ10 among them. Its pooled results are for antioxidants as a group; the abstract gives no separate figure for CoQ10.

The reviewers describe the current evidence as inconclusive, because of serious risk of bias, poor reporting of live births and pregnancies, high attrition and small trials. The earlier 2019 version of the review (Smits 2019) had also rated its evidence low to very low quality.

The MOXI trial (Steiner 2020)

The Males, Antioxidants, and Infertility (MOXI) trial was a multicentre, double-blind, placebo-controlled trial at nine US fertility centres in 174 men with male-factor infertility. The antioxidant formula contained vitamin C 500 mg, vitamin E 400 mg, selenium 0.20 mg, L-carnitine 1,000 mg, zinc 20 mg, folic acid 1,000 µg and lycopene 10 mg daily; it did not contain CoQ10. After 3 months, there were no significant differences in sperm morphology, motility or DNA fragmentation, and cumulative live birth at 6 months did not differ (15% with antioxidants vs 24% with placebo). The authors concluded that antioxidants did not improve semen parameters or DNA integrity, and that, although the trial was limited by sample size, treating the male partner did not appear to improve pregnancy or live-birth rates.

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The Bentov & Casper IVF Trial

Yaakov Bentov and Robert Casper at the Toronto Centre for Advanced Reproductive Technology and Mount Sinai Hospital in Toronto led the first randomized trial of CoQ10 in older women having IVF, after their group's work in aged mice.

Bentov & Casper 2013 (Fertility and Sterility review)

A review titled “The aging oocyte — can mitochondrial function be improved?” It discusses possible causes of age-related decline in female fertility, presents evidence for a central role of mitochondrial dysfunction and oxygen radicals, and explores CoQ10 deficiency as a contributing factor and the effects of giving CoQ10. It is a review, not a trial.

Bentov 2014 (Clinical Medicine Insights: Reproductive Health)

A double-blind, placebo-controlled randomized trial:

Results:

The paper's competing-interests statement discloses that one author had a consultancy agreement with a maker of a CoQ10 product.

The same Toronto group's mouse study (Ben-Meir 2015) is described in the oocyte section above; its findings come from animals and have not been confirmed by a completed human trial of the same design.

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Xu 2018 — Young Women with Poor Ovarian Reserve

Xu and colleagues in Beijing published a randomized controlled trial in 2018 (Reproductive Biology and Endocrinology) in women classed as POSEIDON group 3: under 35 years old, with poor ovarian reserve measures before stimulation.

Design

Results

The authors concluded that CoQ10 pretreatment improved ovarian response and embryo measures in young women with poor ovarian reserve, and that further work is required to find out whether it affects clinical endpoints such as pregnancy and live birth. The trial was in women under 35, so it does not directly test CoQ10 in older women.

Bar chart comparing CoQ10 with control in two IVF trials: in Bentov 2014, aneuploid eggs were 46.5% with CoQ10 against 62.8% with placebo and clinical pregnancy 33% against 26.7%, neither difference significant; in Xu 2018, the fertilization rate was 67.49% against 45.06%, a significant difference, while cumulative live birth was 28.95% against 15.54%, not significant; a side panel summarises the Lafuente 2013 meta-analysis, the 2022 and 2020 Cochrane reviews and the MOXI trial. COQ10 IVF TRIALS: LAB MEASURES AND BIRTHS percent in each group · ns = not statistically significant CoQ10 600 mg/day placebo or no pretreatment Aneuploid eggs Bentov 2014, ages 35-43 46.5% 62.8% · ns Clinical pregnancy Bentov 2014 33% 26.7% · ns Fertilization rate Xu 2018, under 35 67.49% 45.06% · p = 0.001 Cumulative live birth Xu 2018 28.95% 15.54% · p = 0.08, ns WHAT THE REVIEWS SAY Men: Lafuente 2013 sperm measures rose; no rise in pregnancy; no birth data Men: Cochrane 2022 all antioxidants: live birth OR 1.43, very low certainty Men: MOXI 2020 combination without CoQ10: live birth 15% vs 24% Women: Cochrane 2020 uncertain whether antioxidants raise live birth; very low certainty evidence Sources: Bentov et al. 2014 and Xu et al. 2018 (full texts); Lafuente 2013, de Ligny 2022, Showell 2020, Steiner 2020 (abstracts)

Egg and embryo measures compared with pregnancy and birth outcomes in the two CoQ10 IVF trials, as reported by the trial authors.

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Doses Used in Male-Fertility Trials

These are the regimens the cited trials used. They describe research, not a treatment plan.

The trials used CoQ10 (ubiquinone); none of those cited here compared ubiquinone with ubiquinol for fertility outcomes. Combination products containing zinc, selenium, L-carnitine, vitamins C and E and folate are widely sold for male fertility; the largest placebo-controlled trial of such a combination (MOXI, described above) found no improvement in semen parameters, DNA fragmentation or live birth. Smoking, alcohol, heat exposure, excess body weight and some environmental chemicals are often discussed as factors in sperm quality; they are outside the trials cited on this page.

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Doses Used in Female-Fertility Trials

No trial cited here tested CoQ10 in women trying to conceive without IVF, compared doses, or compared ubiquinol with ubiquinone. The 2020 Cochrane review of antioxidants for female subfertility, which included CoQ10 among 63 trials, is summarised in the FAQ below.

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Combination Therapy (Zinc, Selenium, DHEA, Vitamin D)

In fertility practice CoQ10 is often discussed alongside other supplements. The cited evidence on the combinations is limited:

Men: multi-antioxidant formulas

The MOXI trial tested a daily combination of vitamin C, vitamin E, selenium, L-carnitine, zinc, folic acid and lycopene against placebo in 174 men and found no improvement in semen parameters or DNA integrity, and no difference in live birth (Steiner 2020). The 2022 Cochrane review could not draw conclusions from comparisons of one antioxidant with another, because too few studies compared the same products (de Ligny 2022).

Women: DHEA and other add-ons

DHEA is a hormone, not an antioxidant. The 2024 Cochrane review of androgens for women having assisted reproduction found that DHEA pretreatment likely results in little to no difference in live birth or ongoing pregnancy (OR 1.30, 95% CI 0.95 to 1.76; 9 trials, 1,433 women; moderate-certainty evidence); data on adverse events were sparse (Naik 2024). No trial cited on this page tested CoQ10 combined with DHEA and vitamin D. Inositol, melatonin and DHEA in IVF are covered on the inositol fertility page.

Polycystic ovary syndrome (PCOS)

The one randomized trial of CoQ10 with clomiphene for ovulation induction in clomiphene-resistant PCOS (101 women, published in 2014) was retracted in 2023; the retraction notice in PubMed does not state the reason (El Refaeey 2014; notice PubMed PMID: 37683569). No other CoQ10 trial in PCOS is cited on this page.

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Timing Before IVF: What Was Tested

The two IVF trials gave CoQ10 for about two months before the cycle: two months before and up to egg retrieval (Bentov 2014) and 60 days before the IVF-ICSI cycle (Xu 2018). The rationale offered is that eggs grow and mature over a period of months before ovulation, so a supplement would need time to affect the eggs retrieved.

Neither trial compared different lengths of pretreatment, so claims that CoQ10 must be started a fixed number of days or months before stimulation, or that shorter courses give smaller effects, were not tested in the trials cited here. Neither trial tested CoQ10 in frozen embryo transfer cycles or in donor-egg cycles.

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Patient FAQ

Q: Is there evidence that CoQ10 improves pregnancy rates in women in their late 30s?
Not yet. The one placebo-controlled trial in women aged 35-43 having IVF (Bentov 2014) was stopped early, enrolled fewer women than planned, and found no significant differences in aneuploidy or pregnancy. The 2020 Cochrane review of antioxidants for female subfertility, which included CoQ10 among 63 trials and 7,760 women, was uncertain whether antioxidants improve live birth (OR 1.81, 95% CI 1.36 to 2.43; 13 trials, 1,227 women; very low-quality evidence) and found that they may improve clinical pregnancy (OR 1.65, 95% CI 1.43 to 1.89; 35 trials, 5,165 women; low-quality evidence), with no difference in miscarriage (Showell 2020). The reviewers concluded that there is limited evidence in support of oral antioxidants for subfertile women.

Q: Does CoQ10 help men with low sperm motility?
In men with idiopathic asthenozoospermia, placebo-controlled trials and a meta-analysis found improved sperm measures such as motility and concentration (Balercia 2009; Lafuente 2013), though one trial found no significant change (Nadjarzadeh 2011). The meta-analysis found no increase in pregnancy rates, and none of its trials reported live births (Lafuente 2013).

Q: What doses were used in the IVF trials?
Both IVF trials used 600 mg/day for about two months before the cycle (Bentov 2014; Xu 2018). Different durations were not compared.

Q: Ubiquinol or ubiquinone for fertility?
The fertility trials cited here describe their supplement as CoQ10; the Bentov and Xu reports describe CoQ10 capsules rather than ubiquinol, and the Balercia trials measured ubiquinol in semen after giving CoQ10. No cited trial compared the two forms for fertility outcomes.

Q: Was 600 mg/day well tolerated?
In the Xu 2018 trial no local or systemic side effects were reported over 60 days, although 16 women stopped because they found the three-times-a-day schedule hard to keep up. A 2008 safety review, written by employees of a CoQ10 manufacturer, put the observed safety level from clinical trials at 1,200 mg/day (Hidaka 2008). The 2022 Cochrane review found that antioxidants as a group may cause more mild stomach upset in men (de Ligny 2022).

Q: What is known about CoQ10 during pregnancy?
In a randomized, double-blind, placebo-controlled trial in 235 women at increased risk of pre-eclampsia, CoQ10 200 mg/day from 20 weeks of pregnancy until delivery was associated with less pre-eclampsia (14.4% vs 25.6%; RR 0.56; 95% CI 0.33-0.96) (Teran 2009). Published safety data in pregnancy are limited to small trials of this kind.

Q: What about donor-egg IVF?
The rationale for CoQ10 in IVF is the aging of the woman's own eggs. No trial cited here tested CoQ10 in donor-egg cycles.

Q: What about PCOS-related infertility?
The only randomized trial of CoQ10 in PCOS found for this page was retracted in 2023 (El Refaeey 2014). Inositol in PCOS is covered on the inositol fertility page.

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Safety and Interactions

Decisions about supplements during fertility treatment belong with a clinician, because they interact with the treatment protocol.

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Key Research Papers

  1. Balercia G, Mosca F, Mantero F, Boscaro M, Mancini A, Ricciardo-Lamonica G, Littarru G. (2004). Coenzyme Q(10) supplementation in infertile men with idiopathic asthenozoospermia: an open, uncontrolled pilot study. Fertility and Sterility 81(1):93-98. — PubMed PMID: 14711549
  2. Balercia G, Buldreghini E, Vignini A, Tiano L, Paggi F, Amoroso S, Ricciardo-Lamonica G, Boscaro M, Lenzi A, Littarru G. (2009). Coenzyme Q10 treatment in infertile men with idiopathic asthenozoospermia: a placebo-controlled, double-blind randomized trial. Fertility and Sterility 91(5):1785-1792. — PubMed PMID: 18395716
  3. Lafuente R, González-Comadrán M, Solà I, López G, Brassesco M, Carreras R, Checa MA. (2013). Coenzyme Q10 and male infertility: a meta-analysis. Journal of Assisted Reproduction and Genetics 30(9):1147-1156. — PubMed PMID: 23912751
  4. Safarinejad MR. (2009). Efficacy of coenzyme Q10 on semen parameters, sperm function and reproductive hormones in infertile men. Journal of Urology 182(1):237-248. — PubMed PMID: 19447425 — The journal published an expression of concern in 2023 (doi:10.1097/JU.0000000000003110).
  5. Bentov Y, Casper RF. (2013). The aging oocyte—can mitochondrial function be improved? Fertility and Sterility 99(1):18-22. — PubMed PMID: 23273985
  6. Bentov Y, Hannam T, Jurisicova A, Esfandiari N, Casper RF. (2014). Coenzyme Q10 supplementation and oocyte aneuploidy in women undergoing IVF-ICSI treatment. Clinical Medicine Insights: Reproductive Health 8:31-36. — PubMed PMID: 24987272
  7. Xu Y, Nisenblat V, Lu C, Li R, Qiao J, Zhen X, Wang S. (2018). Pretreatment with coenzyme Q10 improves ovarian response and embryo quality in low-prognosis young women with decreased ovarian reserve: a randomized controlled trial. Reproductive Biology and Endocrinology 16(1):29. — PubMed PMID: 29587861
  8. Ben-Meir A, Burstein E, Borrego-Alvarez A, Chong J, Wong E, Yavorska T, et al. (2015). Coenzyme Q10 restores oocyte mitochondrial function and fertility during reproductive aging. Aging Cell 14(5):887-895. — PubMed PMID: 26111777 — Mainly an animal (mouse) study.
  9. Nadjarzadeh A, Sadeghi MR, Amirjannati N, Vafa MR, Motevalian SA, Gohari MR, Akhondi MA, Yavari P, Shidfar F. (2011). Coenzyme Q10 improves seminal oxidative defense but does not affect on semen parameters in idiopathic oligoasthenoteratozoospermia: a randomized double-blind, placebo controlled trial. Journal of Endocrinological Investigation 34(8):e224-e228. — PubMed PMID: 21399391
  10. Smits RM, Mackenzie-Proctor R, Yazdani A, Stankiewicz MT, Jordan V, Showell MG. (2019). Antioxidants for male subfertility. Cochrane Database of Systematic Reviews 3:CD007411. — PubMed PMID: 30866036 — Superseded by the 2022 update (de Ligny 2022).
  11. Showell MG, Mackenzie-Proctor R, Jordan V, Hart RJ. (2017). Antioxidants for female subfertility. Cochrane Database of Systematic Reviews 7:CD007807. — PubMed PMID: 28752910 — Superseded by the 2020 update (Showell 2020).
  12. Van Blerkom J, Davis PW, Lee J. (1995). ATP content of human oocytes and developmental potential and outcome after in-vitro fertilization and embryo transfer. Human Reproduction 10(2):415-424. — PubMed PMID: 7769073 — Replaces an off-topic entry (a zebrafish insecticide study, Wang 2010) that had been cited here for oocyte mitochondria.
  13. de Ligny W, Smits RM, Mackenzie-Proctor R, Jordan V, Fleischer K, de Bruin JP, Showell MG. (2022). Antioxidants for male subfertility. Cochrane Database of Systematic Reviews 5(5):CD007411. — PubMed PMID: 35506389
  14. Showell MG, Mackenzie-Proctor R, Jordan V, Hart RJ. (2020). Antioxidants for female subfertility. Cochrane Database of Systematic Reviews 8(8):CD007807. — PubMed PMID: 32851663
  15. Steiner AZ, Hansen KR, Barnhart KT, Cedars MI, Legro RS, Diamond MP, et al.; Reproductive Medicine Network. (2020). The effect of antioxidants on male factor infertility: the Males, Antioxidants, and Infertility (MOXI) randomized clinical trial. Fertility and Sterility 113(3):552-560.e3. — PubMed PMID: 32111479
  16. Battaglia DE, Goodwin P, Klein NA, Soules MR. (1996). Influence of maternal age on meiotic spindle assembly in oocytes from naturally cycling women. Human Reproduction 11(10):2217-2222. — PubMed PMID: 8943533
  17. Naik S, Lepine S, Nagels HE, Siristatidis CS, Kroon B, McDowell S. (2024). Androgens (dehydroepiandrosterone or testosterone) for women undergoing assisted reproduction. Cochrane Database of Systematic Reviews 6(6):CD009749. — PubMed PMID: 38837771
  18. El Refaeey A, Selem A, Badawy A. (2014). Combined coenzyme Q10 and clomiphene citrate for ovulation induction in clomiphene-citrate-resistant polycystic ovary syndrome. Reproductive BioMedicine Online 29(1):119-124. — PubMed PMID: 24813752 — Retracted (retraction notice: PubMed PMID: 37683569)
  19. Hidaka T, Fujii K, Funahashi I, Fukutomi N, Hosoe K. (2008). Safety assessment of coenzyme Q10 (CoQ10). BioFactors 32(1-4):199-208. — PubMed PMID: 19096117
  20. Spigset O. (1994). Reduced effect of warfarin caused by ubidecarenone. Lancet 344(8933):1372-1373. — PubMed PMID: 7968059
  21. Engelsen J, Nielsen JD, Winther K. (2002). Effect of coenzyme Q10 and Ginkgo biloba on warfarin dosage in stable, long-term warfarin treated outpatients. A randomised, double blind, placebo-crossover trial. Thrombosis and Haemostasis 87(6):1075-1076. — PubMed PMID: 12083489
  22. Engelsen J, Nielsen JD, Hansen KF. (2003). Effect of Coenzyme Q10 and Ginkgo biloba on warfarin dosage in patients on long-term warfarin treatment. A randomized, double-blind, placebo-controlled cross-over trial. (article in Danish, English abstract) Ugeskrift for Laeger 165(18):1868-1871. — PubMed PMID: 12772396
  23. Teran E, Hernandez I, Nieto B, Tavara R, Ocampo JE, Calle A. (2009). Coenzyme Q10 supplementation during pregnancy reduces the risk of pre-eclampsia. International Journal of Gynaecology and Obstetrics 105(1):43-45. — PubMed PMID: 19154996

PubMed Topic Searches

  1. PubMed: CoQ10 male fertility sperm motility
  2. PubMed: CoQ10 IVF oocyte quality
  3. PubMed: ubiquinol IVF pretreatment
  4. PubMed: oocyte mitochondria aneuploidy
  5. PubMed: poor ovarian responder CoQ10 DHEA
  6. PubMed: male fertility antioxidant stack

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Connections

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