The fertility supplement market is large, profitable, and largely unregulated. Patients preparing for IVF are a receptive audience — understandably so, because the desire to do everything possible before a cycle is very human. The problem is that most supplements sold for fertility have limited, conflicting, or no clinical evidence behind them.
This guide reviews the supplements most commonly discussed in IVF contexts, what the evidence actually shows, and where the uncertainty lies.
The Evidence Standard to Keep in Mind
The HFEA categorises fertility treatment add-ons (including some supplements) into a traffic light system based on evidence. Most supplements fall into the red or amber categories — meaning either no evidence of benefit or evidence that is insufficiently robust to recommend routinely.
A supplement "working" in a small study does not mean it improves live birth rates in a larger, properly controlled trial. Many early positive findings in fertility research do not replicate. Be cautious of confident claims.
CoQ10 (Coenzyme Q10)
What it's claimed to do: Improve egg quality by supporting mitochondrial energy production in oocytes.
What the evidence shows: There is biological plausibility — eggs are metabolically demanding cells and mitochondrial function declines with age. Some small studies have shown improvement in egg quality markers and fertilisation rates. However, there are no large, well-controlled randomised trials demonstrating improved live birth rates.
Who might consider it: Patients with low ovarian reserve or poor previous egg quality, particularly over 35. Some fertility consultants recommend 200–600mg/day for 3–6 months before a cycle.
Verdict: Plausible mechanism, insufficient evidence for live birth benefit. Low risk. May be worth trying if you have poor ovarian reserve and time before your cycle, but do not expect certainty of benefit.
DHEA (Dehydroepiandrosterone)
What it's claimed to do: Increase ovarian response to stimulation in poor responders by supporting androgen environment in the ovaries.
What the evidence shows: DHEA has been studied specifically in poor ovarian responders (patients who produce few eggs despite stimulation). Some studies show modest improvements in follicle number and live birth rates in this group. A 2021 meta-analysis suggested modest benefit in poor responders.
Caution: DHEA is androgenic — it raises testosterone levels. It should not be used in patients with PCOS/PMOS or those with high AMH, as it may worsen hyperandrogenism. It is typically prescribed or supervised rather than self-prescribed.
Who might consider it: Patients classified as poor ovarian responders (low AMH, low AFC, previous poor response). Only with consultant supervision.
Verdict: Some evidence of benefit in poor responders specifically. Not for general use or in PMOS patients.
Inositol (Myo-Inositol and D-Chiro-Inositol)
What it's claimed to do: Improve insulin sensitivity and egg quality, particularly in patients with PCOS/PMOS.
What the evidence shows: This is one of the better-evidenced supplements in the fertility context. Inositol (particularly myo-inositol) has been shown in multiple studies to improve insulin resistance, reduce androgen levels, and improve egg quality and IVF outcomes in patients with PCOS. The biological mechanism is understood — inositol is a second messenger in the insulin signalling pathway.
Who might consider it: Patients with PCOS/PMOS, insulin resistance, or irregular ovulation. Also sometimes used in patients with poor egg quality without a PCOS diagnosis.
Verdict: Reasonable evidence, particularly for PMOS patients. Low risk. Often combined with folic acid. See PCOS renamed PMOS: what it means for IVF patients.
Vitamin D
What it's claimed to do: Support implantation and egg quality; deficiency is associated with worse IVF outcomes.
What the evidence shows: Vitamin D deficiency is very common in the UK (due to limited sunlight), and observational studies consistently show an association between adequate vitamin D levels and better IVF outcomes. However, whether supplementing in those who are deficient causes the improvement, or whether the association reflects something else, is harder to prove causally.
Who might consider it: Almost everyone in the UK, given widespread deficiency. NHS guidance recommends 10 micrograms/day for the general UK population, particularly in autumn and winter.
Verdict: Correcting deficiency is low-risk and sensible. Whether supplementing above adequate levels improves outcomes is unclear.
Folic Acid
What it's claimed to do: Reduce neural tube defect risk in early pregnancy.
What the evidence shows: Strong evidence. Folic acid supplementation in the periconception period is established NHS guidance — 400 micrograms/day for women trying to conceive and in the first 12 weeks of pregnancy. Women with certain medical conditions or family history may need higher doses (5mg).
Verdict: Not optional — this is a standard recommendation with strong evidence. Start before you begin IVF preparation if you have not already.
Melatonin
What it's claimed to do: Reduce oxidative stress in follicles, improving egg quality.
What the evidence shows: Melatonin is present in follicular fluid and has antioxidant properties. Some small studies have shown improved fertilisation rates and embryo quality. Evidence is limited and no large trial has confirmed live birth benefit.
Who might consider it: Sometimes considered in poor responders or patients with previous poor egg quality. Typically taken at night, 3mg, for 6–8 weeks before egg collection.
Verdict: Plausible mechanism, limited evidence. Low risk at standard doses.
Omega-3 Fatty Acids
What it's claimed to do: Support embryo quality and reduce inflammation.
What the evidence shows: Omega-3 has general health benefits and some evidence for positive effects on sperm quality. Evidence for improving IVF outcomes in women is limited but some observational studies suggest association with better embryo quality.
Verdict: Low risk, general health benefit regardless of fertility effect. Reasonable to include.
What Is Not Worth Taking
Supplements with no meaningful evidence: Many branded "fertility supplements" combine multiple vitamins and minerals with minimal evidence for any of the individual components at the doses used. The labelling is often misleading.
High-dose antioxidants in male partners: There is some evidence that high-dose antioxidant supplementation in men with sperm DNA fragmentation may help. However, indiscriminate high-dose antioxidant use is not evidence-based. See sperm DNA fragmentation.
Frequently Asked Questions
Q: When should I start taking supplements before IVF?
A: For supplements targeting egg quality (CoQ10, DHEA, inositol), 3–6 months before the cycle is typically recommended — the rationale is that the eggs recruited in a stimulated cycle completed their initial maturation up to 90 days before collection. For folic acid, start as soon as you are trying to conceive. For vitamin D, correcting deficiency can begin at any point.
Q: Should I tell my clinic what supplements I am taking?
A: Yes, always. Some supplements interact with medications or affect hormone levels. Your clinic needs a complete picture of what you are taking.
Q: Can I take supplements during stimulation?
A: Some should be stopped during stimulation — check with your clinic. DHEA is typically stopped before or at the start of stimulation. Others (folic acid, vitamin D, inositol) are generally continued. Always confirm with your clinic.
Q: Do fertility supplements make up for poor egg quality?
A: No supplement reliably reverses age-related decline in egg quality. They may support optimal conditions in the time before collection, but they are not a substitute for realistic prognosis-setting with your consultant, particularly if you are over 38.
Q: My partner is also taking supplements. Which ones actually help for male fertility?
A: The evidence is somewhat stronger for male supplementation than for women's egg quality supplements. Antioxidants (vitamin C, vitamin E, CoQ10), zinc, selenium, and omega-3 have evidence for modest improvement in sperm parameters. Refer to a reproductive urologist or andrologist if your partner has significant sperm abnormalities.
This article is for information only. Discuss any supplements with your fertility consultant before your IVF cycle, as interactions and contraindications vary.