Fertility Supplements for Women Over 35: What to Take and Why

Fertility supplements for women over 35 are nutritional compounds taken to support egg quality, hormonal balance, and the biological foundations of conception during the years when natural fertility begins to decline more steeply. The strongest evidence supports a small, targeted set — not the long ingredient lists found on many supplement labels.

Why does fertility change after 35?

Female fertility declines progressively from the late 20s, with the rate of decline accelerating after 35. Two biological shifts drive this. The first is a falling number of remaining eggs — the ovarian reserve — measured indirectly by anti-Müllerian hormone (AMH).¹ The second is a decline in egg quality, driven largely by reduced mitochondrial efficiency inside the oocyte and the gradual accumulation of oxidative damage.²

The mitochondria inside an oocyte produce the ATP needed for chromosomal segregation during meiosis; impaired mitochondrial function is mechanistically linked to age-related meiotic errors.^2,3 The accumulation of these errors raises aneuploidy rates and is widely recognised as the single biggest contributor to lower implantation rates and higher miscarriage rates after 35.

Targeted supplementation cannot reverse these biological shifts, but a focused strategy can address several of the modifiable inputs — providing the substrates the oocyte uses to make ATP, supporting antioxidant systems that limit oxidative damage, and correcting nutrient gaps that affect ovulation, hormone production, or early embryo development. Foundational evidence here comes from animal models showing that CoQ10 supplementation can restore oocyte mitochondrial function in aged mice,³ with subsequent human trials beginning to map the same pathway in clinical settings (see CoQ10 section below).

Which fertility supplements have the strongest evidence for women over 35?

Five supplements form the core evidence-supported foundation for women over 35 trying to conceive. Each addresses a specific modifiable mechanism rather than offering generic "fertility support".

Folic acid: the only universally recommended preconception supplement

Folic acid is the only fertility-related supplement recommended for every woman planning a pregnancy, regardless of age. The UK National Institute for Health and Care Excellence advises 400 micrograms (0.4 mg) daily during the time a woman is trying to conceive and continuing until the end of the 12th week of pregnancy.⁴ A higher dose of 5 mg daily is recommended for those at increased risk of neural tube defects, and is available on prescription.⁴

After 35, methylation efficiency tends to decline alongside other age-related metabolic shifts, which is part of the rationale some practitioners give for choosing methylated folate (5-methyltetrahydrofolate, or 5-MTHF) over standard folic acid. The clinical evidence for routine 5-MTHF in over-35s without an MTHFR polymorphism remains limited, however, and folic acid at the 400 µg dose remains the guideline-backed default.⁴

Vitamin D: correct any deficiency, but don't oversupplement

Vitamin D is involved in ovarian folliculogenesis, endometrial receptivity, and reproductive hormone signalling. The Cozzolino 2020 systematic review and meta-analysis in Fertility and Sterility did not find a significant overall effect of vitamin D status on clinical pregnancy or live birth rates in women undergoing IVF, although several of the included primary studies suggested better outcomes in vitamin-D-sufficient women than in deficient ones.⁵ Correcting deficiency remains the most defensible interpretation of the current evidence; routine high-dose supplementation in women who already have sufficient levels has not been shown to add fertility benefit.⁵

Public Health England recommends 10 micrograms (400 IU) of vitamin D daily for adults during autumn and winter, with year-round supplementation for those at higher risk of deficiency. Women planning pregnancy who suspect deficiency should ask a GP for a 25-hydroxy vitamin D blood test before increasing intake, particularly above 1,000 IU.

Omega-3 (EPA/DHA): more evidence than most realise

A 2022 prospective cohort study of 900 women published in Human Reproduction found that women aged 30–44 trying to conceive had a per-cycle probability of conceiving 1.51 times that of non-users if they were taking omega-3 supplements (fecundability ratio 1.51, 95% CI 1.12–2.04), after adjustment for age, obesity, race, previous pregnancy, vitamin D status, and prenatal/multivitamin use.⁶ The mechanism is thought to involve reduced systemic inflammation, improved oocyte membrane fluidity, and possible effects on follicular fluid composition.⁶

Combined EPA and DHA totalling 500–1,000 mg per day is a typical evidence-based range. Choose a fish oil with third-party purity certification, or an algal DHA product for plant-based diets.

CoQ10: the headline supplement for the over-35 ovary

Coenzyme Q10 is a mitochondrial cofactor that the body produces less efficiently with age. Endogenous synthesis begins to decline in early adulthood and continues to fall through the reproductive years, mirroring the broader pattern of age-related cellular energy decline.⁷

The most cited trial in this space is Bentov et al. 2014, a randomised double-blind placebo-controlled study that gave 600 mg of CoQ10 daily to women aged 35–43 undergoing IVF.⁸ The trial was terminated early on safety grounds related to the polar body biopsy procedure and was underpowered to detect differences in oocyte aneuploidy. Subsequent randomised data from Xu et al. 2018, in 169 women under 35 with poor ovarian response, showed CoQ10 pretreatment for 60 days produced significantly higher numbers of retrieved oocytes, higher fertilisation rates, and more high-quality embryos compared to controls.⁹

Ubiquinol — the reduced form of CoQ10 — is generally recommended for women over 35 because the body's ability to convert standard ubiquinone declines with age. A typical dose is 200 mg of ubiquinol daily, taken with food. Higher doses up to 600 mg are sometimes used in clinical fertility settings but should be discussed with a clinician.

A high-quality prenatal multivitamin

A daily prenatal multivitamin provides the broader micronutrient base that supports ovulation, hormone production, and early embryo development. Key inclusions to check on the label: iodine (150 µg), vitamin B12 (preferably methylcobalamin), zinc, selenium, and choline. UK women of child-bearing age frequently fall short on iodine, B12 (especially on plant-based diets), and choline.

Which supplements should I consider beyond the core five?

Two further compounds have meaningful evidence in specific contexts and may be worth discussing with a fertility-aware clinician.

Myo-inositol is best known for its role in PCOS, but a smaller body of research has examined it in non-PCOS women undergoing IVF. A 100-woman pilot study in non-PCOS patients under 40 by Lisi et al. found that adding myo-inositol to folic acid for 3 months before IVF stimulation significantly reduced the total gonadotropin dose required for follicular maturation; total oocytes retrieved were lower in the myo-inositol group, and clinical pregnancy and implantation rates did not differ significantly between groups.¹⁰ The standard supplement dose is 2 g taken twice daily (4 g total) for at least 3 months. For women over 35 without PCOS, the rationale rests on its insulin-sensitising and oocyte-quality effects rather than ovulation induction.

N-acetylcysteine (NAC) is a precursor to glutathione, the body's main intracellular antioxidant. Its strongest evidence base is in PCOS-related ovulation, but trials in women undergoing IVF have shown improvements in oocyte and embryo quality. NAC at 600 mg twice daily has been used in fertility trials, though it should be discussed with a clinician before adding to an existing supplement stack.

A third supplement, DHEA (dehydroepiandrosterone), is a hormone — not a nutritional compound — and is reserved for women with diminished ovarian reserve (DOR) under the supervision of a fertility specialist. A 2025 systematic review and meta-analysis of 38 randomised controlled trials in women with DOR found that DHEA, testosterone, high-dose gonadotropins, and delayed-start protocols all improved the number of oocytes retrieved during IVF stimulation; effects on clinical pregnancy and live birth rates were less consistent across treatments, although testosterone supplementation showed a statistically significant live-birth improvement (odds ratio 2.19, 95% CI 1.11–4.32).¹¹ DHEA is not appropriate as a routine "over 35" supplement and is included here only to counter the misconception that it is.

How long do fertility supplements take to work in women over 35?

Egg cells go through a roughly 90-day maturation window before ovulation, progressing from the resting primordial follicle pool through preantral, antral, and finally pre-ovulatory stages. Any supplement intended to influence egg quality therefore needs at least three full menstrual cycles to act on the cohort of follicles that will ovulate at the end of that period.

In practical terms, three months is the minimum trial period for assessing whether CoQ10, omega-3, myo-inositol, or NAC is making a measurable difference. Most fertility clinics recommend starting supplementation 3–6 months before active conception attempts or before an IVF cycle. Folic acid should ideally be started 3 months before conception to build folate stores for early pregnancy.⁴

For women over 35 trying to conceive naturally, a reasonable framework is to start supplements, give them three full cycles, and seek a fertility assessment if conception has not occurred after 6 months of regular unprotected intercourse.

What should I avoid taking over 35 when trying to conceive?

Several common supplement choices warrant caution.

• High-dose vitamin A as retinol is teratogenic. Stay below the upper limit of 700 µg/day from supplements (carotenoid forms in food are not the same risk).
• Herbal stimulant compounds marketed for fertility (yohimbe, high-dose DHEA self-prescribed, some Chinese herb blends) lack safety data in pregnancy.
• Ashwagandha and other adaptogens have limited preconception safety data — discuss with a clinician before adding.
• Multiple overlapping prenatals or "fertility complexes" stacked on top of one another can push intakes of zinc, iron, and vitamin A above safe ceilings.
• Energy drinks and high-caffeine pre-workouts are not supplements, but caffeine intake above 200 mg/day during conception attempts and early pregnancy is widely advised against.

Specific interactions worth flagging: CoQ10 may reduce the anticoagulant effect of warfarin, and high-dose omega-3 may add to bleeding risk on blood thinners or before surgery. If you are taking medication for thyroid dysfunction, blood pressure, depression, anticoagulation, or any chronic condition, check supplement interactions with a pharmacist before starting.

Frequently Asked Questions

Can fertility supplements actually improve egg quality after 35?

Supplements cannot create new eggs or reverse age-related decline in the resting follicle pool. They can support the metabolic environment in which existing follicles mature — particularly mitochondrial energy production (CoQ10), antioxidant defence (NAC, vitamin E), and methylation (folate, B12). The realistic framing is "support the egg quality you have", not "boost it back".

Should I take ubiquinol or ubiquinone for fertility over 35?

Ubiquinol is the reduced, biologically active form of CoQ10 that the body uses directly. The conversion from ubiquinone to ubiquinol declines with age, which is why most fertility specialists recommend ubiquinol for women over 35. A typical dose is 200 mg/day of ubiquinol, taken with a fat-containing meal for absorption.

Do I still need folic acid if I'm taking a prenatal multivitamin?

Most quality prenatal multivitamins include 400 µg of folic acid or methylfolate, so a separate folic acid supplement is not required if the prenatal label confirms this dose. Read the label carefully and avoid duplicating the dose, which can mask vitamin B12 deficiency at very high intakes.

How is supplementation different at 40+ compared to 35?

The same biological mechanisms continue to drive fertility changes, but the rate of decline accelerates and ovarian reserve markers (AMH, antral follicle count) typically fall further. Supplement choices remain similar but the case for starting earlier, considering ubiquinol over standard CoQ10, and seeking an early fertility assessment becomes stronger. NAC and myo-inositol also become more frequently considered.

Are fertility supplements safe to keep taking into early pregnancy?

Folic acid should be continued through the first 12 weeks of pregnancy.⁴ Vitamin D and a prenatal multivitamin can typically be continued throughout pregnancy. CoQ10, myo-inositol, and NAC are usually stopped at a positive pregnancy test, as data on continued use during pregnancy is limited. Always confirm with a midwife or obstetrician.

Can my partner take fertility supplements at the same time?

Yes — a parallel male fertility supplement strategy is recommended for couples trying to conceive at any age. Sperm production takes approximately 74 days, so men should begin supplementation at the same time. See our companion guide for couples for the detail.

What if I don't see results after three months?

If three months of consistent supplementation has not been followed by conception (assuming regular unprotected intercourse), supplement choice is rarely the limiting factor. A formal fertility assessment with a GP or fertility clinic — covering AMH, antral follicle count, semen analysis, and tubal patency — is more likely to identify the actionable issue than further supplement trials.

Supporting Your Fertility with FertilitySmart

Fertility nutrition over 35 works best as part of a broader strategy that combines a Mediterranean-style fertility diet, regular physical activity, prioritised sleep, and stress reduction alongside the supplement core described above.

At FertilitySmart, we offer both fertility supplements for women and fertility supplements for men, each formulated with the nutrients discussed in this guide — including folic acid, vitamin D, CoQ10, and a comprehensive micronutrient base. Explore our range of evidence-based fertility supplements formulated for couples planning pregnancy at every age.

Related Reading

• How to Improve Egg Quality Naturally
  The pillar guide to the science of egg quality and the lifestyle and supplement levers that influence it.
• Trying to Conceive at 35+
  The wider TTC strategy for the over-35 reader, covering timing, lifestyle, and when to seek specialist input.
• What Does CoQ10 Do for Fertility?
  Single-supplement deep dive on the most discussed compound for older eggs.
• Vitamin E for Fertility
  The antioxidant case for vitamin E in egg quality support.
• Magnesium and Fertility
  The often-overlooked mineral that underpins hundreds of metabolic reactions relevant to conception.
• Fertility Diet
  The Mediterranean-style eating pattern with the strongest fertility evidence base.
• Top 10 Fertility Supplements
  The broader supplement landscape with evidence-graded entries.
• Boost Fertility in Your 40s Naturally
  The same logic applied to the next age band.
• Myo-Inositol for Fertility and PCOS
  Detailed breakdown of inositol mechanism, dosing, and PCOS-specific protocols.

References

1. La Marca A, Sunkara SK. Individualization of controlled ovarian stimulation in IVF using ovarian reserve markers: from theory to practice. Hum Reprod Update. 2014;20(1):124-140. doi.org/10.1093/humupd/dmt037
2. Wang T, Babayev E, Jiang Z, et al. Mitochondrial unfolded protein response gene Clpp is required to maintain ovarian follicular reserve during aging, for oocyte competence, and development of pre-implantation embryos. Aging Cell. 2018;17(4):e12784. doi.org/10.1111/acel.12784
3. Ben-Meir A, Burstein E, Borrego-Alvarez A, et al. Coenzyme Q10 restores oocyte mitochondrial function and fertility during reproductive aging. Aging Cell. 2015;14(5):887-895. doi.org/10.1111/acel.12368
4. National Institute for Health and Care Excellence. Maternal and child nutrition: nutrition and weight management in pregnancy, and nutrition in children up to 5 years (NG247). NICE; 2025. nice.org.uk/guidance/ng247
5. Cozzolino M, Busnelli A, Pellegrini L, Riviello E, Vitagliano A. How vitamin D level influences in vitro fertilization outcomes: results of a systematic review and meta-analysis. Fertil Steril. 2020;114(5):1014-1025. doi.org/10.1016/j.fertnstert.2020.05.040
6. Stanhiser J, Jukic AMZ, McConnaughey DR, Steiner AZ. Omega-3 fatty acid supplementation and fecundability. Hum Reprod. 2022;37(5):1037-1046. doi.org/10.1093/humrep/deac027
7. Hernández-Camacho JD, Bernier M, López-Lluch G, Navas P. Coenzyme Q10 supplementation in aging and disease. Front Physiol. 2018;9:44. doi.org/10.3389/fphys.2018.00044
8. Bentov Y, Hannam T, Jurisicova A, Esfandiari N, Casper RF. Coenzyme Q10 supplementation and oocyte aneuploidy in women undergoing IVF-ICSI treatment. Clin Med Insights Reprod Health. 2014;8:31-36. doi.org/10.4137/CMRH.S14681
9. Xu Y, Nisenblat V, Lu C, et al. Pretreatment with coenzyme Q10 improves ovarian response and embryo quality in low-prognosis young women with decreased ovarian reserve: a randomized controlled trial. Reprod Biol Endocrinol. 2018;16(1):29. doi.org/10.1186/s12958-018-0343-0
10. Lisi F, Carfagna P, Oliva MM, et al. Pretreatment with myo-inositol in non polycystic ovary syndrome patients undergoing multiple follicular stimulation for IVF: a pilot study. Reprod Biol Endocrinol. 2012;10:52. doi.org/10.1186/1477-7827-10-52
11. Conforti A, Carbone L, Di Girolamo R, et al. Therapeutic management in women with a diminished ovarian reserve: a systematic review and meta-analysis of randomized controlled trials. Fertil Steril. 2025;123(3):457-476. doi.org/10.1016/j.fertnstert.2024.09.038

Marina Carter

Health & Fertility Writer at FertilitySmart

Marina translates reproductive health research into accessible, evidence-led guidance for individuals and couples planning pregnancy. Her work focuses on the science of preconception nutrition, egg and sperm quality, and the broader lifestyle factors that influence fertility outcomes. Read Full Bio →