Copper chlorophyll complexes
A copper-stabilised version of the natural green plant pigment chlorophyll, used to keep food looking green during processing and storage.
The EU's food safety regulator concluded in 2015 that it could not complete a safety assessment because too few studies exist. It could not rule out genotoxic or carcinogenic potential for the water-soluble form. The additive is still permitted but its long-term safety profile remains unresolved.
What is it?
E141 is made by extracting chlorophyll from green plants such as grass, alfalfa, nettles or spinach, then replacing the central magnesium atom in the molecule with copper. The copper version is far more stable than natural chlorophyll (E140): it resists fading under heat, light and acidity. Two forms are approved: E141(i) is oil-soluble (copper phaeophytins) and E141(ii) is water-soluble (sodium and potassium copper chlorophyllin salts).
What does it do?
Acts as a green colourant. Where unmodified chlorophyll would turn khaki during cooking, canning or long shelf storage, the copper-substituted complex holds its bright green colour. This makes it useful in processed foods where appearance would otherwise deteriorate.
Where you will see it
Ice cream, dairy desserts and yogurts; green confectionery such as mint sweets and jellies; soft drinks; canned peas and green vegetables; mint sauce; soups and sauces. On a UK label it appears as 'E141', 'copper complexes of chlorophylls', or 'copper complexes of chlorophyllins'.
What the science says
EFSA could not complete a safety assessment in 2015
When EFSA re-evaluated E141 in 2015 it found the evidence base too thin to reach a safety conclusion. Studies on how the body absorbs, distributes and excretes these compounds were lacking, as were adequate long-term toxicity and carcinogenicity studies. As a result EFSA stated that the safety of E141 cannot be assessed and recommended withdrawing the existing acceptable daily intake figure rather than endorsing it.
EFSA concluded that reliable data on absorption, distribution, metabolism, excretion, genotoxicity, chronic toxicity, carcinogenicity, and reproductive and developmental toxicity of copper complexes of chlorophylls and chlorophyllins were lacking, and that their safety of use as food additives cannot be assessed.
The EFSA Panel recommended that the existing ADI (set by JECFA at 0-15 mg/kg body weight) should be withdrawn because the data supporting it were judged inadequate.
Genotoxic and carcinogenic potential could not be ruled out for the water-soluble form
EFSA found that the data available on copper chlorophyllins (E141(ii)) were inadequate to evaluate genotoxic potential. It also noted discrepancies and uncertainties in the data on carcinogenic potential, and called for further, adequate studies before a conclusion could be drawn.
The available data were considered inadequate by the EFSA Panel to evaluate the genotoxic potential of copper complexes of chlorophyllins (E141(ii)).
Given discrepancies and uncertainties in the available data concerning carcinogenic potential of copper chlorophyllins, EFSA called for further and adequate evaluation of possible carcinogenicity before any conclusion could be reached.
Systemic absorption of copper chlorophyllins sets them apart from non-copper versions
Unlike plain chlorophyll (E140), where intestinal absorption is considered negligible, studies showed that at least one component of the water-soluble copper chlorophyllin form can be absorbed and distributed around the body. This matters because systemic exposure is what determines potential for toxic effects in organs, and it undermined the assumption that E141 behaves like an inert pigment that passes straight through.
In contrast to non-copper chlorophylls and chlorophyllins, available data showed that some components of copper chlorophyllins can be absorbed and distributed systemically in animals.
Rat feeding experiments estimated intestinal absorption of copper chlorophyllin and its appearance in serum and organs, concluding that at least one major component is effectively absorbed and that further pharmacokinetic studies are needed.
Copper contribution from E141 at typical food use levels is negligible
A 2023 EFSA re-evaluation of copper from all dietary sources looked at exposure from E141 among other inputs. It found that the amount of copper contributed by food-grade chlorophyll colourants at permitted levels adds negligibly to total dietary copper, meaning E141 is unlikely to tip copper intake above the revised health guidance value in the population as a whole.
The 2023 EFSA re-evaluation of health-based guidance values for copper found that the contribution from copper-containing food additives including E141 to overall dietary copper exposure was negligible.
EFSA revised the tolerable upper intake for copper to an ADI of 0.07 mg/kg body weight per day (approximately 5 mg/day for a 70 kg adult), lowering it from the previous 0.15 mg/kg value, based on hepatic copper accumulation as an early marker of toxicity.
Copper and Wilson's disease
Wilson's disease is a rare inherited disorder where the body cannot properly excrete copper, leading to its accumulation in the liver, brain and other organs. People with this condition are advised to limit all dietary sources of copper, including copper-containing food additives. The condition affects roughly 1 in 30,000 people.
Wilson's disease involves mutations in the ATP7B gene that impair hepatic copper excretion, causing progressive copper accumulation. Medical guidance for affected individuals includes restriction of high-copper dietary sources.
European Commission issued a call for further data
Following the 2015 EFSA opinion, the European Commission formally called on industry to submit the missing toxicological and absorption data so a full re-evaluation could be completed. As of the mid-2020s, no completed follow-up EFSA opinion has been published, and the additive remains authorised in the EU and UK while data collection continues.
The European Commission issued a call for scientific and technical data on permitted food additives E140(i), E140(ii), E141(i) and E141(ii) as a follow-up to EFSA's 2015 re-evaluation opinions identifying data gaps.
Where it stands with the regulators
Who should be careful
People with Wilson's disease or other inherited copper metabolism disorders should limit additional copper from all sources, including food additives. Look for 'E141', 'copper complexes of chlorophylls', or 'copper complexes of chlorophyllins' in the ingredients list.
The honest read
E141 sits in an unusual position: it is a long-authorised additive that has never been removed from the approved list, yet the EU's food safety regulator could not complete a safety assessment when it formally reviewed the evidence in 2015. The data gaps are real - there are genuinely too few studies on how the body handles these compounds over time, and the question of whether the water-soluble form carries any genotoxic or carcinogenic potential has not been resolved. The European Commission has asked industry to fill these gaps, but no completed follow-up opinion has been published. This is not a case where concerns have been investigated and set aside; it is a case where the investigation stalled at the data-collection stage. The copper contribution from typical food use appears to be small relative to dietary copper as a whole, but the fundamental toxicological questions remain open.
Related additives
Common questions
Is E141 banned in the UK?
No. E141 remains approved and permitted in the UK under the assimilated EU Regulation 1333/2008. However, the EU's food safety regulator (EFSA) concluded in 2015 that it could not complete a safety assessment because key toxicological data were missing, and recommended withdrawing the acceptable daily intake figure. The additive continues to be used while regulators wait for industry to supply the missing data.
Why did EFSA withdraw the ADI for E141 in 2015?
EFSA found that the studies underpinning the original acceptable daily intake set by JECFA (0-15 mg/kg body weight) were inadequate. There were too few studies on absorption, long-term toxicity and carcinogenicity to assess whether the existing limit was protective. EFSA could not rule out genotoxic or carcinogenic potential for the water-soluble form. Withdrawing the ADI reflected the absence of reliable data rather than evidence of specific harm at current use levels.
What foods contain E141?
Mint sweets and confectionery, green jellies, ice cream and dairy desserts, soft drinks with a green colour, mint sauce, canned peas and green vegetables, soups and sauces. It can appear on the label as 'E141', 'copper complexes of chlorophylls', or 'copper complexes of chlorophyllins'.
Is E141 vegan?
Yes. E141 is derived entirely from plant material: chlorophyll is extracted from green plants such as grass, alfalfa, nettles or spinach, and copper (a mineral) is then added chemically. No animal-derived ingredients are involved in production.
Sources
- EFSA ANS Panel, Scientific Opinion on re-evaluation of copper complexes of chlorophylls (E 141(i)) and chlorophyllins (E 141(ii)) as food additives, EFSA Journal 2015;13(6):4151
- EFSA Scientific Committee, Re-evaluation of health-based guidance values for copper and exposure assessment from all sources, EFSA Journal 2023, PMC9843535
- UK Food Standards Agency, Approved additives and E numbers
- European Commission, Call for scientific and technical data on permitted food additives E140(i), E140(ii), E141(i) and E141(ii)
- EFSA, Safety and efficacy of copper complexes of chlorophylls for ornamental fish, grain-eating ornamental birds and small rodents and of copper complexes of chlorophyllins for all animal species, EFSA Journal 2016, PMC13093185
- Gomes et al., Bioavailability of dietary sodium copper chlorophyllin and its effect on antioxidant defence parameters of Wistar rats, Journal of the Science of Food and Agriculture, 2009
- International Association of Color Manufacturers, Chlorophylls and chlorophyllins, copper complexes
- Schilsky, Wilson's disease and other neurological copper disorders, PMC4336199
Aaron Keen is the founder of NutraSafe. He researches and writes every additive entry himself, from the primary sources. About the research →
This is a guide, not medical advice. If an additive affects you, speak to your GP or a dietitian.
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