Why NAC and omega-3 are recommended, as part of your FET prep

Jessie Day, in partnership with Zita West Products  |   17 Apr 2024

If you’re anything like us, you’ll identify with getting pretty specific – granular, even – when it comes to IVF prep. 

For an FET (frozen embryo transfer), well, we want the supplements to match. There’s nothing broad-brush about an FET, and we’re looking for a carefully put-together list – ideally, a pack – of the supplements to factor in, when getting ready for transfer day. All backed up with the latest research, of course, and tips for matching dietary support, too. 

So, following a few updates to the Frozen Embryo Transfer Pack by the (legendary) development team at Zita West Products – we wanted to know, why NAC? There’s a lot of buzz around this star player right now, but what makes n-acetyl cysteine (NAC) one to factor in, when preparing for FET? 

And, while we’re at it, let’s get a refresher on omega-3. We know it’s mega-good for our fertility (and tricky to source enough from diet alone), but why give it a top spot in FET prep? 

All of this, and – as always, when chatting to team Zita West – so much more. Let’s dive in. 

Ready to order? TRB readers get 10% off the entire Zita West supplement range (US and UK), with code TRB10* at checkout. 

Preparing for IVF with FET – the focus is implantation

When gearing up for a frozen embryo transfer, we’re not actually focusing (for once, it might seem!) on egg or sperm health, as part of our fertility game plan. 

Remember, your embryo – whether using your own or donated egg and sperm – has already been created. So, the nutritional requirements shift towards supporting implantation, instead of egg and sperm quality. 

Essential micronutrients – vitamin E, selenium, manganese being three of the most crucial – are proven to support implantation, and CoQ10 shows promising significance in enhancing endometrial thickness. Plus, studies indicate a higher intake of fibre may improve those all-important implantation rates. 

You’ll find all of these in one convenient pack here, plus today’s focus nutrients – NAC and omega-3 as brand-new additions. Here’s the deep-dive on why. Hint, think implantation.  


Omega-3 fatty acids are renowned for their powerful anti-inflammatory benefits. This makes them a key tool when preparing for frozen embryo transfer, where implantation can be directly impacted by inflammation in the endometrial lining.

Does omega-3 help implantation?

If you’re navigating conditions like PCOS and/or endometriosis, this will be a key concern. But in general, we’re really aiming to support implantation when looking at our FET prep, with a nurtured and nourished endometrium. For this, we especially want:

  • good blood flow
  • reduced inflammation

Studies show that omega-3 can support across the spectrum of preparation – from uterine blood flow and reduced inflammation to hormonal balance, right across the process.

Which foods are high in omega-3?

Alongside your FET pack (or standalone omega-3 supplement), diet is the cornerstone of really intentional frozen embryo transfer prep.

Most of us struggle to get a sufficient intake of omega-3 from diet alone (particularly if we’re not going for oily fish two or three times a week), so a fab-quality supplement keeps the bases covered. Ultra Omega is an effective option, its phospholipid-based formula providing the same natural fat source we’d find in the body, allowing for superior absorption.

But getting omega-3 in its whole food form is a big plus, and top sources include:

  • oily fish, such as mackerel, salmon, herring, tuna, sardines and anchovies
  • white fish, such as cod
  • nuts – walnuts are especially good
  • seeds – chia and flax are star players
  • natto and egg yolks are also good sources

For inspiration, try out this yummy asparagus and salmon with garlic lemon & butter sauce or spinach, walnut & roasted pear salad with raspberry vinaigrette.


NAC (n-acetyl cysteine)

The research is coming fast on NAC, as a powerful antioxidant with potential to significantly reduce inflammation and balance hormone levels. We’ve written about NAC in the context of repeat miscarriage support, so read up there, and let’s dig into its impact on implantation during FET.

What is NAC?

NAC, short for n-acetyl cysteine, is a powerhouse antioxidant. Made from the amino acid l-cysteine, one of its key functions is to replenish glutathione (your body’s primary antioxidant).

We’re excited to see it included in the refreshed FET pack – studies show that NAC takes a key role in reducing inflammation and managing conditions like PCOS and endometriosis, as well as regulating oxidative stress.

Is NAC good for implantation?

Thanks to its powerful antioxidant properties, NAC can work to reduce inflammation and prime the uterine (endometrial) lining for implantation, providing an optimised environment for an embryo, after transfer.

Initial studies show that NAC may provide significant support across the frozen embryo transfer process – more research is needed, however, and we recommend reading this write-up for deep-dive info.

Some studies suggest that supplementing with NAC could improve the thickness and quality of the uterine lining – again, however, further research is underway in this area.

How long does NAC take to work for fertility?

The research is still in its initial stages. However, one key determinant will be your baseline glutathione levels (read back for more on this), and how much work is needed to restore, boost or maintain these.

Typically, it could take several weeks for NAC to show its benefits. When planning in your prep for frozen embryo transfer, the Zita West team recommend taking your supplement for at least three months before transfer – read up here for the full guidance.

Any NAC foods to know about?

As an amino acid, NAC can be found in higher-protein foods like chicken, turkey, cheese, eggs and legumes.

Whilst it can be obtained through diet, NAC is a ‘rate limiting step’ in glutathione production – in simple terms, if we don’t have sufficient NAC, our body cannot make glutathione.  So, a high-strength supplement may be recommended when our body needs that extra support.

On your FET prep list

Put these on your frozen embryo preparation plan, and pop us any questions on an Insta DM.

  • get 10% off the freshly updated Frozen Embryo Transfer Pack with our exclusive discount code TRB10* ( you can use this one across the complete Zita West range)
  • read more about the role of omega-3 and NAC in IVF prep, in our nutritionist’s starter pack
  • subscribe to our weekly newsletter, for more to-the-minute info and exclusive discounts and giveaways from the experts we rely on, and trust

*TRB10 is valid once per customer only. Excludes subscription purchase. This offer cannot be used in conjunction with any other offer. Zita West terms of the site apply.

Want to receive more great articles like this every day? Subscribe to our mailing list


Tags: , , , , , , ,

Follow Us


WIN 3 one-to-one fertility coaching sessions with a holistic specialist (worth $897)