What is E511?
Complete guide to understanding magnesium chloride in your food
The Quick Answer
E511 is magnesium chloride, commonly known as nigari (in Japanese) or lushui (in Chinese).
It’s used as a firming agent and coagulant, most famously as the traditional ingredient that turns soy milk into tofu.
Most people who eat tofu or processed foods regularly consume trace amounts of it.
📌 Quick Facts
- Category: Firming Agent, Coagulant & Nutrient Supplement
- Found in: Tofu, dairy products, processed vegetables, infant formula
- Safety: FDA-approved (GRAS), EFSA-approved, approved for organic food
- Approved by: FDA, EFSA, JECFA
- Key Fact: Centuries-old traditional food ingredient with excellent safety profile
What Exactly Is E511?
E511 is magnesium chloride (MgCl₂), a white crystalline solid also known as nigari in Japanese or lushui in Chinese.
Magnesium chloride can be extracted from natural seawater (the traditional method used in Asia) or synthetically produced. The compound exists in both anhydrous (no water) and hexahydrate (containing six water molecules) forms. It’s highly hygroscopic, meaning it naturally absorbs moisture from air.
In technical terms, it’s a mineral salt containing magnesium—an essential nutrient—combined with chlorine. It’s used primarily as a firming agent and coagulant in food.
Most famously, magnesium chloride (nigari) is the traditional substance that turns soy milk into tofu—a food preparation technique practiced in Asia for centuries.
Where You’ll Find E511
E511 appears in numerous foods, most notably tofu:
– Tofu and soy products (primary use)
– Dairy products (cheese, ice cream, puddings, creams)
– Processed vegetables and fruits
– Meat and fish products
– Cereals, pasta, breakfast cereals
– Confectionery and pastry
– Beer and wine
– Non-alcoholic beverages
– Infant formula
– Nutritional supplements
– Processed plant-based meat and dairy alternatives
– Sauces, spices, salads
If you eat tofu, you’ve definitely consumed E511. It’s also likely present in processed dairy and vegetables if you consume modern packaged foods.
💡 Pro Tip: Look for “Magnesium chloride,” “Nigari,” “Lushui,” or “E511” on ingredient lists. It’s especially common in tofu, where it may be called “nigari” or simply listed as the coagulant. In infant formula, it’s a standard ingredient providing bioavailable magnesium.
How E511 Works in Food
E511 serves multiple critical functions in food production.
As a coagulant in tofu: This is the oldest and most traditional use. When magnesium chloride solution is added to hot soy milk, the magnesium ions interact with soy proteins, causing them to precipitate and solidify into tofu. This centuries-old technique remains the standard method for traditional tofu production.
As a firming agent: In canned or processed vegetables, E511 firms the texture, preventing mushiness. It keeps fruits and vegetables crisp during canning and preservation.
As a stabilizer: In dairy products like cheese and ice cream, E511 maintains consistency and prevents separation.
As a nutrient supplement: Magnesium chloride provides bioavailable magnesium—an essential mineral required for healthy bones, muscle function, and nerve transmission. It’s used in infant formula to ensure adequate magnesium intake.
Why Do Food Companies Use E511?
E511 solves multiple technical and nutritional challenges simultaneously.
For tofu producers, it’s the traditional and most effective coagulant. For vegetable canners, it prevents the mushy texture that would otherwise result from heat processing. For dairy producers, it stabilizes emulsions and maintains desired textures.
Importantly, E511 provides bioavailable magnesium—an essential nutrient that many modern diets lack. Using E511 as an additive kills two birds with one stone: it achieves necessary food processing functions while providing nutritional benefits.
Is It Safe?
Regulatory authorities confirm E511 is safe for food use.
The FDA classifies magnesium chloride as “Generally Recognized As Safe” (GRAS) when used as a flavoring agent, adjuvant, and nutrient supplement. The EFSA approves it as a food additive. Most remarkably, it’s approved for organic food—the highest safety certification available.
The 2019 EFSA safety re-evaluation found no adverse effects even in long-term animal studies. Mice exposed to magnesium chloride for 96 weeks showed no harmful effects and no treatment-related tumors.
✓ Safety Confirmed: The EFSA’s 2019 assessment of magnesium chloride found no adverse effects in chronic toxicity studies and no carcinogenic potential. FDA rates it GRAS (Generally Recognized As Safe).
The EFSA’s 2019 Safety Assessment
The European Food Safety Authority’s comprehensive 2019 re-evaluation provides authoritative reassurance.
Key findings:
– No adverse effects observed in 96-week mouse study
– No treatment-related tumours detected
– No concern with genotoxicity (genetic damage)
– No concern with carcinogenicity (cancer)
– No reproductive toxicity (safe for pregnancy and reproduction)
– Very low acute toxicity (LD50: 8,100 mg/kg in rats)
– Not bioaccumulative (doesn’t build up in the body)
Safety at food use levels is confirmed beyond reasonable doubt.
Understanding the Laxative Connection
At VERY HIGH quantities, magnesium chloride can have a laxative effect—but this is irrelevant at food additive levels.
Magnesium salts (like magnesium sulfate) have a well-known laxative effect when consumed in large quantities. However, this effect occurs only at high doses—far above what anyone would consume from eating food containing E511.
Food additive levels of E511 pose no laxative risk. You would need to consume unreasonably large amounts of the pure substance to experience this effect. Standard food use results in negligible magnesium chloride consumption.
Magnesium as Essential Nutrient
E511 provides bioavailable magnesium—an essential mineral for human health.
Magnesium is required for:
– Bone and teeth health
– Muscle function and relaxation
– Nerve transmission
– Energy production
– Heart rhythm regulation
– Enzyme function
Using E511 as a food additive contributes meaningful magnesium to the diet, supporting overall health. This is why it’s included in infant formula—ensuring developing babies receive adequate magnesium.
Centuries of Traditional Use
E511 has the most documented food use history of any modern additive.
Magnesium chloride (nigari) has been used to make tofu in Japan and China for centuries. This traditional use, practiced across generations without documented harm, provides real-world evidence of safety. The technique remains essentially unchanged from hundreds of years ago—soy milk is coagulated with nigari solution to create tofu.
When USDA organic standards were established in 1995, magnesium chloride was approved for organic food use—reflecting the recognition that it’s a naturally derived, safe ingredient with deep cultural roots.
Natural Source Options
Magnesium chloride can be naturally extracted from seawater.
The traditional method, particularly in Asia, involves extracting magnesium chloride directly from seawater. This natural source approach appeals to consumers seeking “natural” ingredients. Whether from seawater extraction or synthetic production, food-grade E511 must meet identical purity and safety specifications.
Toxicity Data
Magnesium chloride demonstrates very low toxicity even at high doses.
– LD50 (lethal dose in 50% of test subjects): 8,100 mg/kg—indicating very low acute oral toxicity
– NOAEL (No Observed Adverse Effect Level): >1,000 mg/kg in 54-day rat study—no adverse effects even at high doses
– Chronic 96-week study: No adverse effects, no tumors in mice
– No genetic damage: Negative in genetic toxicity tests
– Not bioaccumulative: Doesn’t build up in tissues
Food use levels are thousands of times below doses tested in safety studies.
Regulatory Approval Across Regions
E511 approval is nearly universal:
– United States (FDA): GRAS—Generally Recognized As Safe
– European Union (EFSA): Approved food additive
– International (JECFA): FAO/WHO approved as INS 511
– Organic standards: Approved by USDA, EC, IFOAM, Japan Agricultural Standards
– Codex Alimentarius: Permitted in multiple food categories
This universal approval across different regulatory systems supports the safety assessment.
Vegan, Vegetarian, and Allergen Status
E511 is suitable for:
– Vegan diets ✓
– Vegetarian diets ✓
– Gluten-free diets ✓
– Organic diets ✓
Magnesium chloride is a mineral compound with no animal products or byproducts involved in production or extraction.
The Bottom Line
E511 (magnesium chloride/nigari) is a mineral additive used as a firming agent and coagulant in numerous foods, most famously traditional tofu.
Regulatory authorities worldwide classify it as safe, with the FDA rating it GRAS and the EFSA confirming “no safety concern in current authorised use and use levels.”
Its centuries-long history in traditional Asian cuisine provides real-world evidence of safety across generations.
The 2019 EFSA re-evaluation found no adverse effects even at high doses in long-term animal studies.
At normal food use levels, actual exposure is thousands of times below doses associated with any health concern.
Most importantly, it provides bioavailable magnesium—an essential mineral that supports bone, muscle, nerve, and heart health.
As always, food labels must declare E511 when used, enabling informed consumer choice.