Open Instagram, type "fertility supplement", and you will be sold a stack of eight bottles for £90 a month before you have finished scrolling. As a GP, I get asked about these every week. As someone who was once the woman Googling supplements at midnight, I understand exactly why.
So here is the honest version: what UK guidance actually recommends, what has some evidence, what has none, and what to avoid. It applies whether you are trying naturally or preparing for IVF.
The two that everyone should take
Folic acid
The one supplement with unambiguous evidence. Folic acid reduces the risk of neural tube defects such as spina bifida. The NHS advises 400 micrograms a day from before you conceive until the twelfth week of pregnancy. Because the neural tube closes in the first weeks, often before a positive test, "before you conceive" is the point.
Some people need the higher 5 milligram dose, available on prescription from your GP:
- A BMI of 30 or over
- Diabetes
- Taking anti-epilepsy medication
- A previous pregnancy affected by a neural tube defect, or a family history in either partner
- Coeliac disease or other conditions that affect absorption
- Sickle cell disease or thalassaemia
If any of those apply, ask. It is a two-minute conversation and it matters.
Vitamin D
The NHS advises 10 micrograms (400 IU) a day for everyone in the UK between October and March, and all year round if you are pregnant, breastfeeding, have darker skin, or spend little time outdoors. If you are trying to conceive, take it all year. Low vitamin D is common in the UK, particularly in South Asian, Black and Middle Eastern communities, and it is cheap to correct.
Things to avoid
- Vitamin A (retinol) in supplement form, and liver or liver products. High doses can harm a developing baby. Check any multivitamin: pregnancy and conception formulas leave it out for this reason.
- Cod liver oil, because of the vitamin A. Plain fish oil is a different product.
- Anything with "proprietary blend" and no doses on the label. If you cannot see how much is in it, you cannot judge it.
- High-dose anything without a reason. More is not better, and some fat-soluble vitamins accumulate.
The maybes: some evidence, no guarantee
Coenzyme Q10
The most-asked-about supplement for "egg quality". The theory is plausible: it supports energy production in cells, and eggs are energy-hungry. The evidence is small studies, mostly in women with a poor response to IVF drugs, with mixed results and no convincing effect on live birth. Low risk of harm, moderate cost. If you take it, know that you are buying a maybe.
Myo-inositol
Mainly studied in PCOS, where it may improve ovulation regularity and some metabolic markers. Evidence on pregnancy and live birth rates is weaker and inconsistent. NICE does not recommend it as a fertility treatment. Again, low risk, uncertain benefit.
Omega-3
Good for general health and pregnancy; the evidence that it improves conception is thin. Two portions of fish a week, one oily, gets you there through food.
Antioxidants for men
Vitamin C, vitamin E, zinc, selenium and similar are widely sold for sperm quality. The best available review of the trials rates the evidence for improving live birth as low quality. If a semen analysis shows a problem, the more useful conversation is with a clinician about causes, not with a supplement website about cures.
What about a "fertility multivitamin"?
Fine, if it contains 400 micrograms of folic acid and 10 micrograms of vitamin D and no vitamin A. A branded conception multivitamin is a convenient way to get those two, and most of the other ingredients are along for the ride. A generic pregnancy multivitamin at a fraction of the price usually contains the same things.
If your household income is low, check whether you qualify for the NHS Healthy Start scheme, which includes free vitamins.
Food first, and why that is not a cop-out
Most of what supplement marketing sells you is a feeling of control. The things that reliably improve your chances are unglamorous: not smoking, keeping alcohol to none or very little, a weight in the range your body ovulates best at, enough sleep, and a diet with plenty of vegetables, wholegrains, legumes, fish and olive oil. That Mediterranean-style pattern is associated with better fertility outcomes in several studies, and it costs less than the bottles.
If you have PCOS, endometriosis, thyroid disease or coeliac disease, the diet and supplement conversation is different and worth having with your GP or a registered dietitian, not a comments section.
The short version
- Folic acid 400 micrograms daily, or 5 milligrams on prescription if higher risk, from now.
- Vitamin D 10 micrograms daily.
- No vitamin A supplements or liver.
- CoQ10, inositol and omega-3 are maybes, not musts.
- Spend the rest of the money on food, sleep and, if you need it, another cycle.
The supplements chapter of Fertility Foundations goes through each of these in more depth, including the studies behind the maybes, so you can decide with the evidence in front of you rather than an advert. And if you are about to start treatment, preparing for IVF in the UK: a GP's checklist puts the supplements in context with everything else.
Sources: NHS: planning your pregnancy; NHS: vitamins, supplements and nutrition in pregnancy; NHS: vitamin D; NICE guideline CG156; Cochrane review, antioxidants for male subfertility.