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Is soy sauce gluten-free? A UK guide to soy sauce, tamari and swaps

Most soy sauce is brewed with wheat, so it isn't gluten-free. How to spot safe gluten-free soy sauce and tamari in the UK, and where soy sauce hides.

Published Last reviewed 3 min read

Soy sauce is one of the most common “hidden” sources of gluten, and it catches a lot of people out in the first months after diagnosis. The name suggests it’s just soya, but most soy sauce is brewed with wheat. The good news: gluten-free versions are easy to find in UK supermarkets.

The short answer

Ordinary soy sauce is not gluten-free. Coeliac UK lists soy sauce alongside bread, pasta and couscous as foods that contain gluten, and advises people eating Chinese food to avoid soy sauce and wheat noodles.

Soya beans themselves are gluten-free. The gluten comes from the wheat that is traditionally fermented with the beans to give soy sauce its flavour (Beyond Celiac).

How to tell if a soy sauce is gluten-free

Two checks on the bottle tell you almost everything:

  1. Look for “gluten-free” on the label. In the UK, a food can only be labelled gluten-free if it contains no more than 20 mg/kg (20 parts per million) of gluten. Coeliac UK says foods labelled gluten-free are suitable on a gluten-free diet.
  2. Read the ingredients list. UK law requires cereals containing gluten to be named and emphasised (usually in bold). If you see wheat and there’s no gluten-free claim, put it back.

For a full walk-through of UK labels, see our guide to gluten-free vs “may contain” labelling.

Tamari: usually, but not always, gluten-free

Tamari is a Japanese-style soy sauce that is traditionally made with little or no wheat, so it’s the most common swap. But formulations vary by brand, so don’t assume the word “tamari” means gluten-free. Rely on the gluten-free claim on the label.

As an example of a product we checked: Kikkoman UK’s Naturally Brewed Tamari Gluten free Soy Sauce lists its ingredients as water, soybeans, salt and spirit vinegar, and is labelled gluten-free (Kikkoman UK product page, checked 4 October 2026). Whatever you buy, check the label each time, because recipes can change.

Not an endorsement

We mention this product only as a verified example of what a suitable label looks like. We haven’t tested it, and we aren’t paid to mention it.

Other swaps

  • Coconut aminos, made from fermented coconut sap, contain no soya or wheat and are slightly sweeter and milder than soy sauce. Check the label for a gluten-free claim.
  • Gluten-free stock, a pinch of salt and a little sugar won’t taste like soy sauce, but can add savoury depth to a stir-fry in a pinch.

Where soy sauce hides

Soy sauce turns up in more than dipping bowls. Check the label on:

  • stir-fry sauces, teriyaki and other marinades
  • ready meals, noodle pots and meal kits
  • flavoured tofu and marinated meat or fish (Beyond Celiac notes flavoured or marinated tofu may contain soy sauce)
  • crisps and snacks with “Asian-style” or “teriyaki” flavours
  • salad dressings and glazes

If any of these list wheat (often as “soy sauce (water, soya beans, wheat, salt)”) and aren’t labelled gluten-free, they aren’t suitable.

Eating out and takeaways

Soy sauce is often used in cooking, not just served on the side, so it’s worth asking specifically. Coeliac UK’s takeaway advice for Chinese food is to avoid soy sauce and wheat noodles, choose rice or rice noodles where available, and check whether dishes are cooked in the same pan or oil as gluten-containing foods.

Questions to ask:

  • Is soy sauce used in this dish, or in the marinade? Do you have a gluten-free one?
  • Are woks and pans cleaned between dishes?
  • Is the fryer shared with battered or breaded food?

By law, caterers must be able to provide information on allergens, including cereals containing gluten, in the food they sell; our eating out guide explains your rights and what to ask.

Cooking at home

Gluten-free soy sauce or tamari can generally be used in place of regular soy sauce in recipes. Keep a separate, clearly labelled bottle if you share a kitchen with people who use ordinary soy sauce. Our cross-contamination guide has more ideas for mixed households.

Frequently asked questions

Is soy sauce gluten-free?

Usually not. Traditional soy sauce is brewed with wheat, and Coeliac UK lists soy sauce among foods that contain gluten. Choose a soy sauce or tamari that is labelled gluten-free.

Is tamari always gluten-free?

No. Tamari is traditionally made with little or no wheat, but recipes vary by brand. Only rely on tamari that is labelled gluten-free, and check the ingredients list for emphasised wheat.

Is soya itself gluten-free?

Yes. Soya beans do not contain gluten. The gluten in ordinary soy sauce comes from the wheat used to brew it.

Can I eat soy sauce at a Chinese restaurant or takeaway?

Coeliac UK advises avoiding soy sauce and wheat noodles when eating Chinese food, unless the business can confirm a gluten-free sauce and safe preparation. Ask about sauces and marinades, and about shared woks and fryers.

Sources

  1. Coeliac disease and the gluten free diet (healthcare professional presentation), Coeliac UK. Accessed 4 October 2026.
  2. Safe gluten free options for takeaways, Coeliac UK. Accessed 4 October 2026.
  3. How to read food labels, Coeliac UK. Accessed 4 October 2026.
  4. Is soy gluten-free?, Beyond Celiac. Accessed 4 October 2026.
  5. Commission Implementing Regulation (EU) No 828/2014 (as retained in UK law), legislation.gov.uk. Accessed 4 October 2026.
  6. Kikkoman Naturally Brewed Tamari Gluten free Soy Sauce (product page), Kikkoman UK. Accessed 4 October 2026.