Science & methodology

How HerCode actually works.

This page is for readers who want to know what's behind the product. HerCode personalises pregnancy nutrition guidance using selected nutrient-related genetic markers, your stage and your diet pattern. NHS, NICE and SACN guidance remain the foundation. We don't diagnose, predict or prevent.

01

What HerCode is, and what it isn't.

HerCode is a nutrition guidance product, not a clinical service. The clearest way to describe it is to say what it does and what it does not do.

What HerCode is

A nutrition guidance product, anchored in NHS guidance.

  • Personalised pregnancy and fertility nutrition guidance.
  • Built on top of NHS, NICE and SACN guidance, not in opposition to it.
  • Informed by selected nutrient-related genetic markers.
  • Shaped by your life stage and diet pattern.
  • Designed to be used alongside your GP, midwife or fertility clinic.
What HerCode is not

A clinical, diagnostic or predictive product.

  • Not a diagnostic test for nutrient deficiency.
  • Not a predictor of pregnancy outcomes for you or your baby.
  • Not designed for ancestry or family relationship analysis.
  • Not designed to predict disease risk.
  • Not a replacement for advice from a qualified healthcare professional.
02

The panel, by nutrient.

HerCode interprets selected markers across nutrient-related genes. The genes we look at are well-described in the published nutrition genetics literature. The specific markers we select, our scoring rules and our recommendation logic are proprietary to HerCode.

Nutrient
Foundation it supports
Genes we look at
Folate
Early neural tube development; one-carbon metabolism.
MTHFR BHMT PEMT
Vitamin B12
Red blood cell formation; one-carbon metabolism.
TCN2 FUT2
Vitamin D
Bone, immune and cell function.
VDR GC
Iron
Red blood cell formation; energy.
TMPRSS6
Choline
One-carbon metabolism; cell membrane function.
PEMT BHMT
Iodine & selenium
Thyroid hormone; early brain development.
Selected markers
Omega-3 (DHA)
Fetal brain and eye development.
FADS1 FADS2
Vitamin A
Cell differentiation; immune function.
BCMO1
11 genes, selected markers, 9 nutrients. Markers are interpreted as part of a nutrient scoring model. A single genetic marker rarely determines nutritional need on its own — recommendations combine marker-level effects into a nutrient-level result, then translate that into practical guidance.
03

How we choose which markers to interpret.

Not every published genetic association is appropriate to act on. HerCode applies four standards to every marker on the panel.

01

Established mechanism

The marker sits in a gene with documented evidence of effect on a nutrient pathway, not on a downstream clinical outcome.

02

Reproducible interpretation

The marker has a clear, reproducible interpretation rule that returns the same recommendation for the same genotype.

03

Within safety guardrails

Any recommended adjustment stays within reference intakes, upper limits and pregnancy-aware safety guidance.

04

Reviewed annually

The full panel is reviewed at least once a year against new published evidence, with sources re-checked and recommendations updated where needed.

Last full review

Methodology, panel and source library reviewed against current UK guidance.

Reviewed April 2026
04

The sources we use, and the ones we don't.

Every nutrition statement HerCode makes is mapped to a source. We use a three-tier hierarchy. Tier 1 sources are the only sources permitted as the sole substantiation for guidance, claims or public-health statistics in customer-facing copy.

Tier 1 · Must-use sources

UK public health, regulatory and systematic-review evidence.

The only sources permitted as sole substantiation for guidance and claims. These are the bodies that set UK pregnancy nutrition guidance, define authorised health claims and provide rigorous evidence reviews.

  • NHS
  • NICE
  • SACN
  • OHID
  • NDNS
  • GB Health Claims Register
  • NHS Digital
  • HFEA
  • RCOG
  • British Society for Haematology
  • BDA
  • British Nutrition Foundation
  • Cochrane systematic reviews
  • PubMed-indexed systematic reviews
  • COT / FSA
Tier 2 · Useful interpretation

Expert and patient-facing context, never used alone for claims.

Permitted for educational copy and contextual framing. Not used alone to substantiate a claim used in advertising or on a product page.

  • Tommy's
  • Miscarriage Association
  • British Thyroid Foundation
  • UK Iodine Group
  • Specialist NHS Trust patient leaflets
  • Academic cohort studies (e.g. ALSPAC)
Excluded · Not used as source of truth

Sources we deliberately don't rely on.

HerCode does not use supplement brand blogs, influencer content, consumer DNA company blogs, non-UK dosage advice (unless explicitly labelled), single mechanistic papers without systematic review context, animal or in vitro studies for consumer claims, or AI summaries quoting other sources second-hand.

05

Three rules that don't bend.

These rules are the floor under everything HerCode says and does. They apply to the report, the website, the emails and the support team alike. If a sentence breaks one of these rules, it doesn't ship.

Rule 01

NHS guidance is the floor, not the ceiling.

Personalisation by HerCode is added on top of NHS, NICE and SACN advice. If our wording could ever be read as overriding or substituting for that guidance, it is wrong, no matter how appealing the line.

Rule 02

We do not diagnose, predict or prevent.

HerCode does not diagnose pregnancy complications, predict outcomes for a baby, or prevent anything. It informs personalised nutrition support around nutrient pathways. This is non-negotiable in any channel.

Rule 03

Every statement is mapped to evidence.

If a statement is not mapped to an authorised health claim, a piece of UK guidance, or a Tier 1 evidence source, it does not get used. "It sounds true" is not evidence.

Want to see how this turns into a plan?

Read the eight pregnancy nutrition foundations HerCode is built around, or start your own personalised plan.