What is E406 (Agar Agar)? – Complete Guide to Natural Gelling Agent

The Quick Answer

E406 is agar agar—a natural gelling agent and thickener extracted from red seaweed (specifically Gelidium and Gracilaria species).

Unlike gelatin, which comes from animal bones and skin, agar is 100% plant-based, making it the preferred choice for vegetarians, vegans, and those seeking natural alternatives.

It’s been used safely for over 300 years, particularly in Asian cuisine, and is approved by all major food authorities.

What Exactly Is Agar Agar?

Agar is a complex carbohydrate (polysaccharide) extracted from red algae. By the FDA’s definition, it’s “a dried, hydrophilic, colloidal polysaccharide extracted from one of a number of related species of red algae.”

In simpler terms: It’s a natural gel-forming substance that turns liquid into a solid when cooled, similar to gelatin but derived from seaweed instead of animal products.

Chemical composition: Agar consists primarily of two polysaccharides—agarose and agaropectin—made up of D- and L-galactose units with some sulfate compounds. It also contains calcium, magnesium, potassium, and sodium.

Key properties:

• Gels at low temperatures: Forms a stable gel at about 37°C (99°F)
• Melts at high temperatures: Dissolves back to liquid at higher heat
• Reversible: Can be gelled and un-gelled multiple times
• High gelling power: Only a small amount needed to create firm gel
• Natural: Exists in nature with a 300-year history of safe use

Where You’ll Find E406

Agar appears in a wide variety of foods:

• Jellies and aspics
• Puddings and custards
• Mousses and foams
• Ice cream and frozen desserts
• Jams and fruit preserves
• Salad dressings and mayonnaise
• Sauces and gravies
• Baked goods
• Plant-based meat and dairy alternatives
• Canned soups and broths
• Dietary and health foods
• Live fermented products (yogurt alternatives)
• Fruit and vegetable spreads
• Confectionery (gummies, soft candies)
• Asian noodle dishes and desserts

It’s particularly common in Asian cuisines, where it’s used to create traditional jellies (like kanten in Japanese cuisine) and in modern vegan desserts as a gelatin replacement.

How Is Agar Produced?

Agar production involves extracting the gel from red seaweed:

Step 1: Harvesting
Red seaweed (Gelidium and Gracilaria species) is harvested from ocean waters or cultivated in coastal farms.

Step 2: Cleaning
The raw seaweed is washed to remove salt, sand, and impurities.

Step 3: Extraction
The seaweed is treated with hot water to dissolve and extract the agar polysaccharides. Chemical solvents may be used in some processes.

Step 4: Purification
The extracted liquid is filtered and concentrated to remove remaining solids and impurities.

Step 5: Freezing and Thawing
Traditional methods freeze and thaw the mixture multiple times to remove more impurities and concentrate the agar.

Step 6: Drying
The agar is dried using heat or freeze-drying to create a powder, flakes, or strips.

The entire process uses only food-grade materials with no synthetic chemicals (though the purification method varies by manufacturer).

Is E406 Safe?

Yes, agar is one of the safest food additives available. Here’s the regulatory evidence:

FDA Status: Generally Recognized As Safe (GRAS) for use as an emulsifier, stabilizer, and thickener in food.

EFSA (European Food Safety Authority): In 2016, after comprehensive safety re-evaluation including studies on genotoxicity, carcinogenicity, and reproductive/developmental toxicity, the EFSA concluded: “There is no safety concern for the general population at the refined exposure assessment for the reported uses of agar as a food additive.”

JECFA (Joint FAO/WHO Committee): Assigned an ADI of “Not Limited”—meaning agar can be safely consumed at any level typically found in food.

Acceptable Daily Intake: No numerical ADI is set. The highest estimated exposure is about 26 mg/kg body weight per day for toddlers (at the 95th percentile), well below any safety concern level.

Health Benefits of Agar

Important note: While these benefits are supported by some scientific evidence, agar is primarily used as a food additive in small quantities. The actual health benefits depend on consuming larger amounts—more like a supplement than a food ingredient. More research is ongoing to fully understand agar’s therapeutic effects.

Potential Side Effects

Agar is generally very well tolerated, but some people may experience side effects, particularly with excessive consumption or if dehydrated:

Common side effects (mild):

• Loose stools or diarrhea (due to laxative effect)
• Loss of appetite
• Weak digestion (temporary)

Rare but serious side effects:

• Esophageal or bowel obstruction (if consumed with insufficient water)
• Phytobezoars (rare fiber ball formations in the GI tract)
• Nausea and vomiting (usually in large amounts or concentrated preparations)
• Dysphagia (difficulty swallowing)

Who Should Avoid Agar?

Agar is safe for most people, but avoid or use with caution if you have:

• Bowel obstruction or swallowing difficulties: Agar can worsen these conditions
• Chronic diarrhea: The laxative effect may worsen symptoms
• Taking laxatives: Additive effect may cause excessive bowel movements
• On blood cholesterol medication: Agar may affect absorption and effectiveness
• Taking medications or supplements: Agar may delay gastric emptying and affect absorption
• Pregnant or breastfeeding: Limited safety data; consult healthcare provider

Rare allergies: Although very uncommon, some people may be allergic to agar or red seaweed. Symptoms include itching, swelling, nausea, or anaphylaxis.

Agar vs Gelatin: Key Differences

Using Agar in Cooking

Basic guidelines for home use:

• Amount: Typically 8-12g per 1 liter of liquid
• Form: Available as powder, flakes, bars, or strips
• Preparation: Dissolve in hot water or liquid, cool to about 37°C to gel
• Temperature: Must be hot to dissolve properly; resists melting until heated to 85°C
• Texture: Creates firm, sliceable gel (unlike soft gelatin)
• Vegan custards: Perfect for dairy-free mousses and puddings

The Bottom Line

E406 (agar agar) is a safe, natural, plant-based gelling agent that has been used successfully for over 300 years. All major food authorities approve it with no numerical safety limits—a sign of exceptional safety.

Key takeaways:

• Safe for most people: Approved by FDA, EFSA, JECFA with “not limited” ADI
• Natural and plant-based: Derived from red seaweed, suitable for vegans
• Health benefits: High in fiber, supports digestive health, aids weight loss
• Versatile: Works in both sweet and savory applications
• Important caveat: Must be consumed with adequate water to avoid bowel obstruction

Unlike many controversial additives, agar’s long history, regulatory approval, and plant-based nature make it a safe and beneficial food ingredient. If you’re avoiding synthetic additives, agar is an excellent choice.