What’s the Deal with Folate?

Over 40% of the population has a genetic folate mutation. Yes. Forty. Per. Cent. That’s nearly half of us walking around with a vitamin-processing glitch like we’re in some kind of nutrient-based Hunger Games.

No, this doesn't mean you’re going to mutate into a Stranger Things-style demogorgon. But it does mean that if you have one of the folate gene variants, your body is likely doing a below-average job of converting folate into the form your cells actually need. And when it comes to fertility? That’s kind of a big deal.

It’s the silent saboteur of egg quality. The under-researched, under-diagnosed, and totally-under-your-GP’s-radar issue that could be wrecking your hormonal harmony, energy levels, and implantation success rate. Let’s break it down.

So... What Even Is Folate?

Great question, hypothetical reader. Folate (aka vitamin B9) is a water-soluble vitamin your body needs to function like a well-oiled, emotionally balanced machine. It helps form red blood cells, supports DNA replication, and is essential for cellular repair, detoxification, and foetal development.

In short: folate is the group chat MVP. She remembers your food allergies, brings bougie snacks, does the washing up and calls your Uber when you’re emotional about your ex. She’s that girl.

It’s also one of the most important nutrients when it comes to growing a human. Like, up there with progesterone that doesn’t nosedive mid-cycle and an LH surge that actually surges instead of ghosting you like a flaky Hinge date.

And yet (shock, horror) it wasn’t until 1991 that researchers accidentally discovered how important folate was for pregnancy outcomes, specifically in preventing neural tube defects. Yes, 1991. The year Nirvana released Nevermind and Silence of the Lambs came out. (Coincidence? Probably.)

That’s how little funding and attention women’s health got (and often still gets): we only figured out this vitamin was crucial for embryonic development when something went tragically wrong. Insert dramatic sigh.

Can’t I Just Take a Folate Supplement?

Oh sweet summer child. If only it were that easy.

Here’s the tea: most high-street supplements contain folic acid, the synthetic version of folate. For roughly half the population, this is totally fine. But for the other half—i.e. those with MTHFR gene mutations—taking folic acid is like pouring oat milk into a diesel car. Useless at best. Problematic at worst.

Why? Because if you have a mutation in the MTHFR gene (short for methylenetetrahydrofolate reductase—but we’re not going to say that again), your body can’t convert folic acid into methylfolate, the active form your cells can actually use. So the folic acid just floats around your system like a passive-aggressive flatmate—taking up space and contributing nothing. And in some cases, it can build up and interfere with normal detox pathways. Not ideal when you’re trying to grow a baby, balance your mood, or just not feel like a walking duvet.

So... What Should I Be Taking?

Drumroll, please: methylated folate, also called 5-MTHF.

This is the bioavailable version of folate. It comes pre-converted, so your body doesn’t need to do any complicated gene-based wizardry to make use of it. If you have a folate-processing mutation, methylfolate sidesteps the entire issue like a clever vitamin ninja.

Look for supplements that contain:

• Methylfolate

• 5-MTHF

• Or explicitly say “active folate” on the label

Our Top Picks:

• Thorne Stress B Complex – Includes methylfolate and a full B-vitamin profile to help support stress and energy

• Pure Encapsulations B-Complex Plus – Clean, third-party tested, and beloved by functional medicine nerds

Avoid budget brands that list only “folic acid” and have more marketing than science behind them. Your uterus deserves better.

How Much to Take?

For those with a known or suspected MTHFR mutation, aim for 800–1000 micrograms per day of methylfolate. If you’re trying to conceive, going through IVF, or freezing your eggs, this becomes non-negotiable. Otherwise, you’re basically throwing £6,000 at your ovaries and whispering, “good luck babes.”

What Happens If I Just Ignore All This?

Look. If you don’t have a mutation, you might be fine. You might cruise through life converting folic acid like a pro, popping a fizzy vitamin tablet and getting pregnant from a gentle sneeze.

But if you do have a mutation (and again, 40%+ of people do), then not addressing it can have some annoying, and sometimes serious, consequences:

1. You’re Constantly Tired

As in: “I got 8 hours of sleep, drank a coffee, and still feel like I just did the Central line at rush hour in July.” You might find yourself being the first to leave the Barry Can’t Swim event, yawning mid-foreplay, or fantasising about nap pods during your follicle scan. Folate is essential for red blood cell production. Low folate means low oxygen delivery to your cells.

2. Your Detox Pathways Are Screwed

Low folate = high homocysteine, which is a marker of poor methylation. Poor methylation = bad detox. That means your body struggles to clear out:

• Estrogen (hello, PMS from hell)

• Histamine (hello, mysterious rashes and mood swings)

• Toxins in general

You might feel moody, puffy, allergic to life, and vaguely unwell in a way no doctor seems able to explain.

3. You Can’t Absorb Nutrients Properly

Low folate often pairs up with low iron, even when your diet is great. You’re eating grass-fed beef and downing green smoothies, yet still somehow look anaemic and feel like a 17th-century maiden in need of smelling salts.

4. It Affects Your Eggs

This is the big one. If you’re thinking about freezing your eggs, going through IVF, or actively TTC, you need optimal folate levels.

Folate deficiency is associated with:

• Poor egg quality

• Failed fertilisation

• Embryo development issues

• Miscarriage

Why risk spending £10k on egg freezing or IVF only to find out you were nutritionally off your game? Not us!

Can I Get Tested for All This?

Yes-ish.

Will My GP Test Folate Levels?

If you go in complaining of fatigue, your GP might test you. Mention fertility and suddenly they’re reaching for the blood forms like it’s Love Island recoupling night. The trick? Be clear and firm:

“Hi, I’d like to check my folate and B12 levels as part of preconception care.”
(Translation: I read the internet. I’m not messing around.)

But here’s the catch: a normal folate result doesn’t actually mean your cells are getting what they need. You can have folate floating around in your bloodstream like a guest who showed up to the party but refuses to engage. Looks present, but slightly useless.

If you’ve got an MTHFR mutation, that folate might not be converting into anything functional, so your cells are essentially ghosted by the one vitamin that was supposed to have their back. Rude.

Should I Test My Genes?

You can! But you don’t have to.

Testing can be helpful if you’re into cycle syncing, have five health podcasts in rotation, and consider your Oura ring part of your personality.

The Two Key Mutations:

• C677T (rs1801133) – the big one. Reduces folate conversion by up to 70%. Roughly 10–15% of the population has this.

• A1298C (rs1801131) – less dramatic, but still worth knowing.

How to Test:

• 23andMe (make sure you export your raw data and analyse it elsewhere)

• SelfDecode

• GeneSight (often used by functional medicine providers)

If testing feels like too much right now, just take the damn methylfolate and move on. Worst case? You pee out some expensive vitamins. Best case? You stop crying every time Mercury goes retrograde.

TL;DR – The Folate Rundown

🧬 40% of people have a genetic mutation that prevents them from processing folic acid.
💊 Most supplements contain folic acid, which is useless (or harmful) for those people.
🥦 Folate is critical for fertility, detox, energy, and egg quality.
✨ The fix? Take methylfolate (5-MTHF) instead.
🩸You can test your folate levels (but don’t trust them blindly) or get genetic testing (optional).

Final Thoughts

Sometimes it feels like there’s a secret language to fertility and women’s health, one where the most important answers are hidden behind acronyms and underfunded research studies. Folate and MTHFR mutations are a perfect example of this: wildly common, deeply impactful, and yet rarely discussed unless you’re already deep in the functional medicine rabbit hole.

You’ve officially levelled up. You understand methylation, you don’t trust folic acid, and you could casually ruin someone’s dinner party with your thoughts on B vitamins. Your eggs? They’re rebranding.