An essential trace mineral and antioxidant-enzyme cofactor where deficiency is virtually nonexistent and the real-world concern is excess, not shortfall
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.
Outcome
Evidence
Effect
Studies
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.
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 9 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 16 Sept 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 2026-09-16}
}
For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.