Is Soy Sauce Gluten Free?

How traditional soy sauce is made

Standard soy sauce (Japanese shoyu, Chinese jiang you) is fermented from soybeans, wheat (often 40–50% of the dry ingredients), salt, and koji mold. The fermentation breaks down most proteins but the finished sauce typically tests well above 20 ppm gluten — sometimes hundreds of ppm.

Safe gluten-free soy sauces and substitutes

• Tamari (gluten free) — a Japanese soy sauce made with 100% soybeans, no wheat. Look for explicit “gluten free” labeling. Brands: San-J Tamari Gluten Free (GFCO certified), Kikkoman Tamari Gluten Free, Eden Foods Tamari.
• La Choy Soy Sauce — in the U.S., La Choy uses hydrolyzed soy protein and is naturally wheat-free, though not explicitly labeled “gluten free.”
• Coconut aminos — slightly sweeter, less salty, completely soy- and wheat-free. Coconut Secret and Bragg are popular.
• Liquid aminos (Bragg, Coco-Aminos) — soy-based but wheat-free.

Restaurant strategy

Most sushi, Chinese, Thai, and Korean restaurants use standard wheat-containing soy sauce by default. Even if you order rice and sashimi, marinades, dipping sauces, and “GF rolls” may be tossed with regular soy. Bring your own GF tamari packets (San-J makes single-serve packets) or call ahead.

Hidden soy-sauce derivatives

Watch for these on labels — they’re soy-sauce-based and usually contain wheat:

• Teriyaki sauce
• Hoisin sauce
• Worcestershire sauce (most brands; Lea & Perrins is GF in U.S. since 1997)
• Oyster sauce
• Black bean sauce
• “Asian-style” marinades and dressings