NutriDex

The Supplement Research Compendium
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Manganese

Mn

An essential trace mineral and antioxidant-enzyme cofactor where deficiency is virtually nonexistent and the real-world concern is excess, not shortfall

Preliminary evidence 🧂Mineral

✚ Updated · How we grade evidence

Evidence tier
Preliminary
Research weight
Citations
8 verified / 8
Classification
Mineral
❝
What the evidence says. Early or small human trials; promising but not yet conclusive.

What is Manganese?

Manganese (Mn) is a mineral used for corrects/prevents true deficiency: required for mnsod antioxidant defense, arginase (urea cycle), glutamine synthetase, and enzymes for bone matrix, cartilage, and glucose/lipid metabolism — but clinical deficiency in free-living people is essentially never seen. NutriDex grades the human evidence as Preliminary. Manganese is an essential trace element that serves as a cofactor for mitochondrial superoxide dismutase (MnSOD), arginase, glutamine synthetase, and enzymes of bone, cartilage, and carbohydrate/lipid metabolism. Frank dietary deficiency is essentially unheard of in humans outside of experimental settings, so it is rarely a limiting nutrient. There are no credible randomized trials showing that manganese supplementation benefits otherwise healthy, non-deficient people, and the dominant clinical literature is instead about toxicity: occupational/airborne and high drinking-water exposure, and overload from manganese-containing parenteral nutrition, all of which cause a Parkinsonian neurotoxicity ("manganism") via basal-ganglia accumulation. Routine manganese supplements are therefore neither needed nor evidence-supported for most adults.

Purported Benefits

✓Corrects/prevents true deficiency: required for MnSOD antioxidant defense, arginase (urea cycle), glutamine synthetase, and enzymes for bone matrix, cartilage, and glucose/lipid metabolism — but clinical deficiency in free-living people is essentially never seen
✓Easily met by diet: whole grains, nuts, legumes, leafy greens, and tea provide ample manganese, so a normal mixed diet covers the AI without supplements
✓Often included in bone-health and multivitamin/multimineral formulas (with calcium, copper, zinc); the combination has weak support and no trial isolates a manganese-specific benefit for bone density
✓No demonstrated benefit in non-deficient adults: there is no robust RCT evidence that manganese supplementation improves cognition, metabolism, joint health, or any clinical outcome in people who are not deficient

Evidence by outcome

The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.

OutcomeEvidenceEffectStudies
Corrects true dietary deficiencyEssential enzyme cofactor, but clinical deficiency is essentially never seen in free-living people; benefit is theoretical. Preliminary ↑ benefit 2
Clinical benefit in non-deficient adultsNo RCT isolates a manganese-specific benefit for cognition, metabolism, joints, or bone in replete people. No Evidence — no effect · negligible
Neurotoxicity from overexposure (manganism)Occupational/parenteral/high-water exposure linked to worse motor and cognitive performance; observational/cohort, not from supplements. Moderate ⚠ risk · large 3

Dosing & Compounds

Typical Dose
Adult Adequate Intake (AI, no RDA established): 2.3 mg/day for men and 1.8 mg/day for women (US IOM). Typical supplemental doses in multivitamins are roughly 1-5 mg. US Tolerable Upper Intake Level (UL): 11 mg/day for adults. EFSA (2023) found data insufficient to set a UL and instead defined a "safe level of intake" of 8 mg/day for adults. Most people meet needs from diet alone and do not require a supplement.
Active Compounds
Supplement salts: manganese sulfate, manganese gluconate, manganese citrate, manganese chloride, and amino-acid chelates (e.g., manganese bisglycinate/aspartate)Common as a minor component of multivitamin/multimineral and bone-support products rather than a standalone supplementDietary sources: whole grains and bran, brown rice, oats, nuts (especially hazelnuts, pecans), legumes, leafy green vegetables, pineapple, and tea (a major contributor)

Safety & Cautions

Oral toxicity from food is rare because gut absorption is tightly homeostatically regulated and >90% is excreted in bile. The serious risks come from routes that bypass this control: chronic inhalation in welders/miners/smelter workers and high manganese in drinking water, and intravenous overload from manganese-containing parenteral nutrition (especially in cholestasis/liver failure and in neonates). Excess manganese accumulates in the basal ganglia and causes "manganism," a Parkinson-like syndrome of tremor, rigidity, gait and cognitive/psychiatric disturbance; T1-weighted MRI shows hyperintense basal-ganglia deposition. Interactions: iron status modulates manganese absorption — iron deficiency increases manganese uptake (and brain accumulation), so iron-deficient individuals may absorb more; hepatic/biliary impairment reduces excretion and raises overload risk. Clinicians should limit or remove manganese from long-term PN, particularly with cholestasis. The UL excludes intakes from such non-dietary sources. Educational only — always check with your doctor or pharmacist before combining Manganese with any medicine.

Key Studies

meta-analysis Vollet/Haynes 2023 (meta-analysis) ✓ PubMed
Meta-analysis of manganese exposure and cognition found significantly poorer processing speed, attention, working memory, reaction time and cognitive control in exposed adults.
systematic review & meta-analysis Liu 2020 (systematic review & meta-analysis) ✓ Full text
Across 55 studies (n=13,388 children), a 10-fold increase in hair manganese was associated with a 2.51-point lower Full-Scale IQ; blood and water manganese showed no significant pooled effect.
meta-analysis Meyer-Baron 2009 (meta-analysis) ✓ PubMed
Pooled 13 studies (958 exposed, 815 unexposed workers); occupational manganese exposure was associated with consistently lower motor and cognitive performance and a long-term linear decline in exposed workers.
review Hardy 2021 (review of PN manganese) ✓ Full text
Reviewed manganese-induced neurotoxicity from parenteral nutrition, noting PN may deliver manganese far exceeding enteral absorption and that cholestasis (reduced biliary excretion) magnifies overload risk.
narrative review Aschner / Erikson — Manganese review (PMC5421128) ✓ Full text
Reviews homeostatic regulation, MnSOD/enzyme cofactor roles, and that toxicity (manganism) arises from inhaled, high-water, or parenteral exposure that bypasses gut regulation, with iron status modulating absorption.
observational / neuroimaging study Aschner 2015 (neuroimaging cohort) ✓ PubMed
Infants on trace-element-supplemented parenteral nutrition showed increased basal-ganglia manganese deposition on T1-weighted MRI correlating with parenteral manganese exposure.
authoritative body / scientific opinion EFSA NDA Panel 2023 ✓ Full text
Concluded data were insufficient to set a Tolerable Upper Intake Level and instead established a 'safe level of intake' of 8 mg/day for adults (including pregnancy/lactation), 2-7 mg/day for younger groups.
authoritative body / reference intakes IOM DRI (Manganese) 2001 ✓ Full text
Set the adult AI at 2.3 mg/day (men) and 1.8 mg/day (women) and a UL of 11 mg/day for adults; noted that human dietary deficiency has not been reported in non-experimental settings.
8 sources cited · 8 verified Search all studies on PubMed ↗

Common questions about Manganese

What is Manganese used for?

Manganese is most often taken for Corrects/prevents true deficiency: required for MnSOD antioxidant defense, arginase (urea cycle), glutamine synthetase, and enzymes for bone matrix, cartilage, and glucose/lipid metabolism — but clinical deficiency in free-living people is essentially never seen, Easily met by diet: whole grains, nuts, legumes, leafy greens, and tea provide ample manganese, so a normal mixed diet covers the AI without supplements, Often included in bone-health and multivitamin/multimineral formulas (with calcium, copper, zinc); the combination has weak support and no trial isolates a manganese-specific benefit for bone density, No demonstrated benefit in non-deficient adults: there is no robust RCT evidence that manganese supplementation improves cognition, metabolism, joint health, or any clinical outcome in people who are not deficient. An essential trace mineral and antioxidant-enzyme cofactor where deficiency is virtually nonexistent and the real-world concern is excess, not shortfall

Does Manganese work — what does the evidence say?

Preliminary evidence. Early or small human trials; promising but not yet conclusive. Manganese is an essential trace element that serves as a cofactor for mitochondrial superoxide dismutase (MnSOD), arginase, glutamine synthetase, and enzymes of bone, cartilage, and carbohydrate/lipid metabolism. Frank dietary deficiency is essentially unheard of in humans outside of experimental settings, so it is rarely a limiting nutrient. There are no credible randomized trials showing that manganese supplementation benefits otherwise healthy, non-deficient people, and the dominant clinical literature is instead about toxicity: occupational/airborne and high drinking-water exposure, and overload from manganese-containing parenteral nutrition, all of which cause a Parkinsonian neurotoxicity ("manganism") via basal-ganglia accumulation. Routine manganese supplements are therefore neither needed nor evidence-supported for most adults.

What is the typical dose of Manganese?

Adult Adequate Intake (AI, no RDA established): 2.3 mg/day for men and 1.8 mg/day for women (US IOM). Typical supplemental doses in multivitamins are roughly 1-5 mg. US Tolerable Upper Intake Level (UL): 11 mg/day for adults. EFSA (2023) found data insufficient to set a UL and instead defined a "safe level of intake" of 8 mg/day for adults. Most people meet needs from diet alone and do not require a supplement.

Is Manganese safe? Any cautions or side effects?

Oral toxicity from food is rare because gut absorption is tightly homeostatically regulated and >90% is excreted in bile. The serious risks come from routes that bypass this control: chronic inhalation in welders/miners/smelter workers and high manganese in drinking water, and intravenous overload from manganese-containing parenteral nutrition (especially in cholestasis/liver failure and in neonates). Excess manganese accumulates in the basal ganglia and causes "manganism," a Parkinson-like syndrome of tremor, rigidity, gait and cognitive/psychiatric disturbance; T1-weighted MRI shows hyperintense basal-ganglia deposition. Interactions: iron status modulates manganese absorption — iron deficiency increases manganese uptake (and brain accumulation), so iron-deficient individuals may absorb more; hepatic/biliary impairment reduces excretion and raises overload risk. Clinicians should limit or remove manganese from long-term PN, particularly with cholestasis. The UL excludes intakes from such non-dietary sources.

How many studies support Manganese?

NutriDex cites 8 sources for Manganese, graded "Preliminary".

Cite this page
APA

Peh, D. (2026). Manganese (Mn): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 2026, from https://nutridex.info/s/manganese

BibTeX
@misc{nutridex_manganese,
  author       = {Peh, Daryl},
  title        = {Manganese (Mn): Benefits, Dosage, Side Effects \& Evidence},
  year         = {2026},
  howpublished = {NutriDex --- The Supplement Research Compendium},
  url          = {https://nutridex.info/s/manganese},
  note         = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

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