Written by Dr Divpreet Sacha. Reviewed by Dr Phoebe Howells. 

Dr Divpreet Sacha is a UK-based GP specialising in fertility and preventative medicine. She works with Neko Health, a preventative health tech company focused on early detection and lifestyle medicine. Divpreet is the creator of the Fertility Foundations programme, an evidence-based online educational programme integrating lifestyle medicine, supplements, exercise, and medical pathways to support fertility. The programme was born from her own experience navigating IVF, miscarriage, and PCOS to help individuals feel informed and empowered throughout their fertility journey.

What is the NG27?

The UK fertility guidelines were updated for the first time in 13 years in March 2026. If you are trying to conceive or preparing to do so, you might be wondering what that means for the care you receive and what, if anything, has changed for you.

NICE, the National Institute for Health and Care Excellence, is the independent body that sets out what best practice looks like for NHS practitioners across England. When NICE publishes a guideline, it sets the floor for the care you're entitled to receive. It doesn't tell your doctor what to do in every situation, but it does define the minimum standard, and crucially, it can prohibit certain conversations from happening at all on the NHS.

Some things have changed. But the questions that matter most to many of the people reading this include: whether your GP can now have a more specific conversation about preconception nutrition, the supplements you are considering, as well as what your numbers actually mean for conception, rather than just population reference ranges. Understanding it gives you more control, not less.

What NICE Does, and What NG257 Changes

NICE produces the clinical guidelines that NHS practitioners across England follow. NG257 replaces guidance that has been in place since 2013, and it is the product of 25 separate evidence reviews.

As I wrote earlier this year, NICE operates at a population level; its purpose is to correct deficiencies and prevent disease, not to optimise fertility for an individual. NG257 does not change that framework.

Why the Supplement and Nutrition Gap Persists

If you were hoping this update would expand what your GP can tell you about preconception nutrition, specific supplements, or whether your vitamin D level is genuinely optimal for conception rather than simply within the NHS reference range, it didn't. The reason is specific.

When NICE sets out to update a guideline, the first step is deciding which questions to review. That scope was set in 2022. Preconception supplementation and lifestyle optimisation were not part of what was being asked. Of 25 evidence reviews conducted for this update, not one examined preconception nutrition or supplementation.

This is not NICE reviewing the evidence on methylfolate, CoQ10, or vitamin D optimisation and finding it wanting. It is those areas that are not being asked about in the first place. The framework NICE uses requires evidence to meet a cost-effectiveness threshold, demonstrate population-level benefit, and be robust enough for NHS implementation. Most of the supplement and lifestyle evidence that matters in a preconception context simply hasn't been studied in that way.

The gap persists because it was never examined.

I trained to believe that clinical excellence meant following the most current, highest-quality evidence available. What I have come to understand, including through my own fertility journey, is that other factors shape what ends up in a guideline: what gets studied, when, and by whom. The evidence above the guideline is not absent. It is structured differently, and the system that produces the floor was not designed to reach it.

Where the Language of the Guideline Matters

Clinical guidelines not only recommend things, but they also prohibit them. The difference between "do not offer" and "consider in selected populations" is the difference between a clinical conversation happening at all.

Before NG257, NICE had not addressed antioxidants for male fertility. The new guideline does. It uses the phrase "do not offer" (Recommendation 1.4.6).

The evidence base NICE drew on includes the MOXI trial (Steiner et al., Fertil Steril. 2020;113(3):552–560), a single randomised controlled trial of one specific antioxidant formulation that did not show a consistent benefit on live birth rates. On that basis, the guideline's position is that NHS clinicians should not recommend antioxidants for men with idiopathic infertility.

The European Association of Urology (2025), the European Society of Human Reproduction and Embryology (2023), and the American Urological Association with the American Society for Reproductive Medicine (amended 2024) all reviewed the same evidence. All three reached a different conclusion: consider antioxidants in selected populations, particularly men with documented oxidative stress or unexplained infertility.

Most antioxidants are low risk and available without a prescription. The clinical question is not whether the NHS should fund them. It is whether a clinician and a patient can even discuss them. Under NG257, on the NHS, that conversation has been formally closed.

A Specific Note for Those With PMOS (formerly PCOS)

The guideline gap doesn't only affect supplementation. For those with PCOS, there is a more immediate practical consequence of this update.

All PCOS-specific guidance has been removed from NG257 while a standalone guideline is being developed, expected in December 2026. In clinical practice, standard ovulation predictor kits can produce misleading results in PCOS, which affects cycle tracking accuracy. Until December, there is no NICE fertility pathway for the most common cause of ovulatory infertility. Specialist support matters more in the interim, not less.

What You Can Actually Do With This

The guideline tells your GP what the minimum standard of care looks like. It does not define what your care has to be.

The supplement and lifestyle evidence that NICE did not review still exists. Form and dose matter, and the research is specific about how. Some examples of this include; 

• Methylfolate may offer some advantages over synthetic folic acid, particularly in individuals with MTHFR gene variants.

• Research suggests CoQ10 may support ovarian response; bioavailability matters here, and not all forms are equal. 

• Form also matters for B12, where Methylcobalamin is the form of B12 most studied in preconception, and B12 deficiency is commonly missed in standard testing.

If sperm health is part of your picture, the same applies to the conversation that NG257 has now formally closed on the NHS. That conversation can still happen. It is just not one your GP can currently initiate.

Staying Informed Without a Scientific Background

Educational resources 

Progress Educational Trust is an independent UK charity that publishes BioNews, a free, regularly updated digest covering fertility science, law, and ethics in accessible language. They have covered NG257 directly, including the questions this article raises. It is one of the few places in the UK where fertility policy is discussed with rigour and without a commercial agenda. Their public events are mostly free to attend.

If you have PMOS

Verity is the UK's PMOS charity. Their booklets, expert resources section, and webinars are produced with clinical input and cover diagnosis, treatment options, and what to expect from specialist care, written for people living with the condition. This is the most useful independent resource available while the standalone NICE PCOS guideline is being developed.

Finding a clinician who can have the conversations your GP currently cannot

The HFEA's clinic finder lets you compare licensed UK fertility clinics on independently verified success rates, inspection outcomes, and patient experience ratings. It is worth using to inform a choice before committing to private care.

For preconception nutrition specifically, the British Dietetic Association runs a searchable directory of HCPC-registered dietitians with a fertility specialism (filter by expertise: fertility). A registered dietitian holds a protected professional title regulated by the Health and Care Professions Council. Nutritionist and health coach are not protected titles. That distinction matters when the conversation involves supplement forms, doses, and how these interact with your specific situation.

The HFEA also publishes its own independent evidence ratings for treatments used alongside IVF, reviewed annually, at hfea.gov.uk/treatments/treatment-add-ons. These ratings use a different framework from NICE and are worth knowing about if you are exploring options beyond what your GP can currently offer.

The next step is not waiting for the guidelines to catch up. It is finding the right support to work with the evidence that already exists.

Key Takeaways

• NICE NG257 (31 March 2026) is the first UK fertility guideline update in 13 years. Preconception supplementation and lifestyle optimisation were not included in the 2022 review scope; of the 25 evidence reviews conducted, none addressed this area. The gap persists because it was never examined. The guideline is a floor; the evidence above it exists and is accessible

• NG257 now explicitly prohibits recommending antioxidants for men on the NHS (Recommendation 1.4.6), a position that diverges from EAU (2025), ESHRE (2023), and AUA/ASRM (amended 2024), all of which recommend consideration in selected populations

• All PMOS guidance has been removed from NG257; a standalone guideline is expected in December 2026; specialist support is especially important in the interim.