Minerals

Manganese

Also known as: Mn, Manganese gluconate, Manganese sulfate, Manganese bisglycinate

The antioxidant-enzyme mineral — essential in tiny amounts, toxic when inhaled, and rarely needed as a supplement.

By IngredientWiki Editorial Team
Fact-checked by IngredientWiki Editorial Team
Updated 2026-09-26
2 min read

In short

Manganese is an essential trace mineral that works as a structural partner in enzymes — most famously manganese superoxide dismutase, a frontline antioxidant in your mitochondria, and the enzymes that build bone and metabolize carbohydrates and amino acids. Deficiency is rare because whole grains, nuts, tea, and leafy greens supply plenty; the public-health concern runs the opposite direction, since inhaled manganese (welding fumes, contaminated water) is neurotoxic. Supplements exist but are needed by very few people, and the upper limit — 11 mg daily — is not far above the RDA.

Cofactor for antioxidant and bone-building enzymes
Abundant in whole grains, nuts, tea, leafy greens
Deficiency is rare; supplements rarely needed
Inhaled manganese is a known neurotoxin (welding)

What is Manganese?

Manganese is the mineral most people have never needed to think about — and that is largely a good thing. Its biological portfolio is impressive: mitochondrial antioxidant defense, bone matrix formation, blood-sugar metabolism, and connective tissue synthesis all depend on manganese-dependent enzymes. But the food supply delivers it so reliably that deficiency is a textbook curiosity, and supplementation is mostly unnecessary. The more important story is toxicity: manganese is one of the few minerals where the danger comes from breathing it, not eating it.

Where it comes from

Natural sources

Whole grains, nuts, legumes, tea, and leafy greens are rich sources
Also in pineapple, spinach, and brown rice
Absorbed in the small intestine; tightly regulated

How it's made

Supplements use manganese gluconate, sulfate, or amino-acid chelates.

What it does in products

Benefits

Enzyme cofactor function

strong evidence

Manganese is required for antioxidant, metabolic, and bone-forming enzymes — an essential role, though supplementation in the already-sufficient does not add benefit.

Bone health support

emerging evidence

Manganese contributes to bone matrix formation, and low intake correlates with poorer bone status — but dedicated bone benefit from supplements is unproven in replete people.

Glucose metabolism

emerging evidence

Manganese-containing enzymes participate in glucose regulation; population studies link both very low and very high manganese with altered glucose handling.

Side effects & safety

Stomach upset (uncommon)At supplemental doses; take with food.

Neurotoxicity risk (rare)From chronic high intake (above the UL) or occupational inhalation — not from food.

Safety considerations

Supplements are unnecessary in pregnancy — prenatal vitamins typically cover needs. Avoid doses above the RDA.
High iron intake can reduce manganese absorption, and vice versa.
Antacids and some antibiotics may reduce mineral absorption — space doses apart.
Not for: Liver disease (impaired manganese clearance)
Not for: Occupational manganese exposure

How it's used

In supplements

Adult AI (adequate intake): 2.3 mg/day for men, 1.8 mg/day for women. Upper limit: 11 mg/day. Most supplements provide 2–10 mg, but routine supplementation is generally unnecessary given abundant food sources.

Regulatory status

Dietary supplement under DSHEA and GRAS nutrient for food fortification.
GRAS (generally recognized as safe) for food use.

Deficiency rare, toxicity real: manganese's unusual risk profile

Most minerals are marketed for their deficiency risks; manganese's risk profile runs the other way. True deficiency, mostly from rare genetic disorders or prolonged total parenteral nutrition, is essentially unheard of in people eating normal diets. Meanwhile, manganese toxicity is a recognized occupational and environmental hazard: chronic inhalation in welding and mining damages the basal ganglia, producing Parkinsonian symptoms. In food and at normal supplement doses, intestinal regulation keeps absorption tightly controlled — which is exactly why most experts suggest skipping the supplement and letting your breakfast oats do the work.

Frequently asked questions

Do I need a manganese supplement?

Almost certainly not. Whole grains, nuts, tea, and greens supply adequate manganese for virtually everyone, and deficiency requires extraordinary circumstances. Unless a clinician identifies a specific need, skip it.

What are the symptoms of manganese deficiency?

Deficiency is extremely rare; reported signs include impaired growth, bone problems, and skin rashes in experimental depletion. Normal dietary intake reliably prevents it.

Is manganese dangerous?

Inhaled manganese is a recognized neurotoxin, and chronic intake above the 11 mg daily upper limit can also harm the nervous system over time. Food intake is safe and self-regulated; high-dose supplements and occupational exposure are the concerns.

The bottom line

Manganese is essential in trace amounts, abundant in food, and rarely worth supplementing — while its toxicity profile, unusual among minerals, rewards restraint. Skip the capsule; eat the oats.

References

Manganese fact sheet for health professionals. NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Manganese-HealthProfessional/
Manganese and superoxide dismutase — literature search. PubMed (National Library of Medicine). https://pubmed.ncbi.nlm.nih.gov/?term=manganese+superoxide+dismutase
Manganese neurotoxicity — literature search. PubMed (National Library of Medicine). https://pubmed.ncbi.nlm.nih.gov/?term=manganese+neurotoxicity+inhalation
Manganese compound records. PubChem (National Library of Medicine). https://pubchem.ncbi.nlm.nih.gov/#query=manganese