Magnesium pyrophosphate
A mineral salt used as a raising agent and acidity regulator in baking, releasing carbon dioxide to help doughs and batters rise.
This is not a permitted food additive in the UK, so you will not normally find it on a UK label.
What is it?
Magnesium pyrophosphate (also called magnesium diphosphate or magnesium dihydrogen diphosphate) is an inorganic salt formed from magnesium and pyrophosphoric acid. It is a white powder, practically insoluble in cold water, that reacts with bicarbonate under heat to produce carbon dioxide.
What does it do?
In baking powders and self-raising flour blends it acts as a slow-release acid component: when the mixture is heated in the oven, it reacts with sodium bicarbonate or potassium bicarbonate to produce carbon dioxide gas, which expands dough and batter. Its low water-solubility means most of the gas release is delayed until baking heat is applied, giving a controlled rise and reducing early gas loss during mixing. It also functions as an acidity regulator, buffering pH in the final baked product.
Where you will see it
Most commonly found in commercial baking powders, self-raising flour, cake mixes, scone mixes, pancake mixes, and some bread improver blends. Less commonly used than the closely related sodium acid pyrophosphate (E450). On a UK ingredient label it appears as 'magnesium pyrophosphate', 'magnesium diphosphate', or simply 'E546'.
What the science says
Magnesium and phosphate as dietary minerals
Both magnesium and phosphate are essential minerals present in far larger amounts in everyday foods such as nuts, seeds, legumes, dairy and wholegrains than in any residue left by E546 in baked goods. At the quantities used in food, the contribution to total dietary magnesium or phosphate intake is small. No independent toxicological concern has been raised for the compound itself distinct from the minerals it contains.
Magnesium dihydrogen diphosphate was authorised as a raising agent and acidity regulator following a review that identified no safety concern at the permitted levels of use.
High phosphate intake in the broader diet
The concern about dietary phosphate is a systemic one covering the entire food supply, not specific to E546. Very high total phosphate intake over long periods is associated with impaired kidney function in people who already have chronic kidney disease. Regulators and dietitians advise people with kidney disease to limit foods high in phosphate additives generally, covering many E-numbers in the 340-452 range including E546. This is a dietary-pattern consideration, not a signal about E546 in isolation.
High dietary phosphate intake is associated with worsening outcomes in people with pre-existing chronic kidney disease; regulatory bodies advise this group to monitor total phosphate from all additive sources.
Where it stands with the regulators
Who should be careful
People with chronic kidney disease are generally advised by their dietitian to limit foods with phosphate additives across the board, since impaired kidneys struggle to excrete excess phosphate. Look for 'E546', 'magnesium pyrophosphate', or 'magnesium diphosphate' on the label.
The honest read
E546 is an inorganic mineral salt that has been used in commercial baking powders for decades. The only population-level discussion touching on it is the broader question of cumulative phosphate additive intake in people with kidney disease, which applies to many phosphate E-numbers, not E546 specifically. There is no independent research raising a concern about the compound itself.
Related additives
Common questions
Is E546 banned in the UK?
No. E546 is an approved food additive in the UK, permitted as a raising agent and acidity regulator under the UK's assimilated version of EU Regulation (EC) No 1333/2008, as amended in 2014.
Should people with kidney disease avoid E546?
People with chronic kidney disease are often advised by their dietitian to limit total phosphate from food additives, as impaired kidneys remove excess phosphate less efficiently. E546 is one of several phosphate-based E-numbers to be aware of. A renal dietitian can advise on specific limits.
What foods contain E546?
E546 is found mainly in commercial baking powders, self-raising flour blends, cake mixes, scone mixes, and pancake mixes. It is less widely used than related phosphate raising agents such as E450 (sodium acid pyrophosphate). On labels it appears as 'magnesium pyrophosphate', 'magnesium diphosphate', or 'E546'.
Is E546 vegan?
Yes. Magnesium pyrophosphate is produced from inorganic mineral sources (magnesium and phosphate salts) with no animal-derived raw materials involved in its manufacture.
Sources
- Commission Regulation (EU) No 298/2014 amending Annex II to Regulation (EC) No 1333/2008 as regards magnesium dihydrogen diphosphate
- UK FSA Approved Additives and E Numbers
- EFSA Scientific Opinion on dietary reference values for phosphorus (2015)
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