Fish collagen and fish allergy, explained from studies and labeling rules.
Fish Collagen Can Be an Allergen
Key point: cod is not on Japan’s allergen-labeling lists
- Salmon△ Recommended item
- Mackerel△ Recommended item
- Cod○ Not listed
- Tilapia○ Not listed
Cod is on neither the 9 mandatory nor the 20 recommended items set by the Consumer Affairs Agency. Among fish, only salmon and mackerel are listed.
*This is a labeling rule; it does not mean cod cannot cause allergy.
Collagen supplements and foods often use fish collagen from skin or scales. Fish collagen is considered one of the major allergens involved in fish allergy.
Summary of the findings:
| Study / report | Finding |
|---|---|
| Challenge study, 30 fish-allergic people (Denmark, 2004) | No one reacted up to 3.61 g fish gelatin |
| Case reports, fish-collagen gummies (Japan, around 2020) | Anaphylaxis caused by fish collagen has occurred |
| Blood of 10 children sensitive to bovine gelatin (Japan) | Only 1 reacted strongly to fish gelatin; no cross-reactivity |
An Oral Challenge Study in Fish-Allergic People
In a Danish double-blind challenge study, 30 people diagnosed with fish allergy (ages 9–50) ate gradually increasing amounts of fish-skin gelatin under medical supervision. None reacted up to a cumulative 3.61 g. One person repeatedly reported mild subjective symptoms at a higher cumulative dose (7.61 g).
30 fish-allergic people, fish gelatin up to 3.61 g
Each dot is one person
● No reaction (30)
The study was small and the amounts limited; it does not mean fish-allergic people can take any amount of fish collagen.
Source：[3]
Reported Reactions to Fish Collagen
In Japan, anaphylaxis after eating gummies containing fish collagen has been reported. In one case, a 9-year-old girl had anaphylaxis after two fruit gummies, and the fish collagen in them was confirmed as the cause. The reporting doctors noted that processed foods may contain fish collagen.
Fish collagen is not allergy-free. People with fish allergy, or who have felt unwell after eating fish, should consult a doctor before using fish collagen.
Bovine and Fish Gelatin Differ
In a study of blood from 10 children who had anaphylaxis to vaccines containing bovine gelatin, only one reacted strongly to fish gelatin, and no cross-reactivity was found between bovine and fish gelatins. Because collagen differs slightly by animal, which collagen a person reacts to varies.
10 children sensitive to bovine gelatin: reaction to fish gelatin
Each dot is one person
● No strong reaction (9) ● Strong reaction to fish gelatin (1)
Source：[5]
Food Allergen Labeling Rules
In Japan, the Consumer Affairs Agency sets which allergens must or should be labeled.
- Mandatory: shrimp, crab, walnut, wheat, buckwheat, egg, milk, peanut, cashew
- Recommended: almond, abalone, squid, salmon roe, orange, kiwifruit, beef, sesame, salmon, mackerel, soybean, chicken, banana, pistachio, pork, macadamia, peach, yam, apple, gelatin
By fish species:
| Fish | Allergen labeling |
|---|---|
| Salmon | Recommended |
| Mackerel | Recommended |
| Cod | Not listed |
| Tilapia | Not listed |
| (Ref.) Gelatin | Recommended |
Among fish, salmon and mackerel are on the recommended list; cod and tilapia are not. This is a labeling rule only and does not mean unlisted fish cannot cause allergy. People with fish allergy should check the fish species used.
Source：[1]
FAQ
Can people with fish allergy take fish collagen?
It depends on the person. One study found no reactions to fish gelatin, but strong reactions to fish collagen have been reported. Consult a doctor first.
How can I find out which fish is used?
Check the ingredient list or the manufacturer’s information, or ask the manufacturer.
What about people allergic to bovine gelatin?
In one study, only 1 of 10 children with anaphylaxis to bovine gelatin reacted strongly to fish gelatin. There are exceptions, so consult a doctor.
Related Pages
Sources
- [1]Consumer Affairs Agency, Food allergy labeling (2026)
https://www.mhlw.go.jp/content/10905000/001704059.pdf - [2]A case of pediatric anaphylaxis caused by gummy tablets containing fish collagen (PMC7610083)
https://pmc.ncbi.nlm.nih.gov/articles/PMC7610083/ - [3]Hansen TK et al., Oral challenge study of the allergenicity of food-grade fish gelatin, Food Chem Toxicol 42 (2004)
https://pubmed.ncbi.nlm.nih.gov/15500940/ - [4]Abe N et al., A case of anaphylaxis due to fish collagen in a gummy candy, Allergol Int 69 (2020)
https://pubmed.ncbi.nlm.nih.gov/31262631/ - [5]Sakaguchi M et al., Reactivity of IgE in bovine gelatin-sensitive children to gelatins from various animals (PMC2326734)
https://pmc.ncbi.nlm.nih.gov/articles/PMC2326734/
This page provides general information and does not indicate the effects or efficacy of any product.