An essential trace mineral used by antioxidant and metabolic enzymes, including manganese superoxide dismutase. Dietary deficiency has essentially never been documented in free-living people.
Manganese is a nutrient almost nobody needs to supplement and many people take without realising, because it is a standard filler in multivitamins, bone formulas and joint blends. Plant-based diets supply it generously — tea, whole grains, nuts and legumes are rich sources — and deficiency in humans is so rare it has only been produced experimentally. The risk sits on the other side: manganese is neurotoxic in excess, producing a parkinsonian syndrome documented in welders inhaling fumes, in people drinking contaminated well water, and in patients on long-term parenteral nutrition. Absorption from the gut is well regulated in healthy people, but liver disease removes that protection because manganese is excreted in bile.
Sold as
Component of multivitamins and bone formulas, Capsule, Tablet, Trace mineral blends
Also known as
Manganese sulfate, Manganese gluconate, Mn
Regulation: The Adequate Intake is 1.8 mg/day for women and 2.3 mg/day for men, with a Tolerable Upper Intake Level of 11 mg/day. Sold as a dietary supplement with no pre-market efficacy review; it appears in many products where it serves no identified purpose.
What the research used
The amounts, forms and durations published trials of Manganese actually administered.
These are the amounts published trials administered — not a recommendation, and not a dose to copy. Trial participants were screened, supervised and given a characterised preparation. What is in a retail bottle is frequently not what was studied, and the amount that suits one person is not general advice.
Studied for Adequate Intake, adults
1.8–2.3 mg
Moderate
An Adequate Intake rather than an RDA. Typical diets supply this comfortably, and plant-based diets often supply several times it.
Studied for Tolerable Upper Intake Level, adults
11 mg
Strong
Set on neurotoxicity. It is easier to approach than it looks: some joint and bone formulas supply 5–10 mg, and dietary intake sits on top of that.
This is general information about food, not medical advice. It cannot diagnose, treat or replace guidance from a clinician who knows your history.
When it was taken
Each window says whether a trial compared it against an alternative, or whether it is convention and pharmacology. Most timing advice is the second kind.
None of the timings below were directly compared in a trial. They reflect how the research happened to dose, or what the pharmacology implies — which is not the same as a timing being better.
🕐Any time
Limited
No timing has been studied. Manganese competes with iron for absorption, so iron deficiency increases manganese uptake — a physiological interaction rather than a dosing schedule.
Timing was not directly compared. This reflects convention or how the compound behaves in the body, not a trial showing this window works better.
The evidence in depth
Best supported: Not enough
What each association actually rests on, and the papers behind it. A rating describes the state of the research, not how promising the supplement sounds. How we rate evidence.
Manganese is included in bone formulas because it is a cofactor for enzymes involved in cartilage and bone matrix formation. No trial has shown that supplementing it affects bone density or fractures in people with adequate intake.
Not enough evidence. Not enough human research to say anything useful yet.
Manganese superoxide dismutase is a key mitochondrial antioxidant enzyme, which is the mechanistic argument for supplementation. There is no evidence that extra manganese increases its activity or changes oxidative stress markers in people who are not deficient.
Not enough evidence. Not enough human research to say anything useful yet.
Meta-analysis · Biological trace element research · 2020 · PMID 31820354
Deep research mode adds each paper’s own conclusion and stated limitations.
Things to know
Interactions, contraindications and dose limits, most serious first. Concentrated extracts interact with medication in ways the whole plant does not, so this section carries more weight here than it does on a food page.
Too much
Neurotoxicity — a parkinsonian syndrome
Manganese accumulates in the basal ganglia and causes manganism, a movement disorder resembling Parkinson disease with tremor, rigidity, gait disturbance and psychiatric changes. It is documented in welders and miners exposed by inhalation, in people drinking contaminated well water and in long-term parenteral nutrition. The syndrome responds poorly to levodopa and is often irreversible.
Worth knowing
Liver disease removes the safety mechanism
Manganese is excreted in bile, so cholestasis or cirrhosis allows it to accumulate even at ordinary intakes. Supplements are a poor idea in any significant liver disease.
Too much
It adds up across products
Multivitamins, bone formulas, joint blends and greens powders all commonly contain manganese, and a plant-rich diet with several cups of tea supplies several milligrams more. Nobody sets out to exceed 11 mg/day, but stacking makes it possible.
Interaction
Iron status changes absorption
Interacts withIron supplements, antacids
Iron deficiency substantially increases manganese absorption because the two share a transporter. People with low iron who take manganese-containing supplements absorb more than they would otherwise.
In the food catalogue
The whole-food form, where one exists. The evidence for a concentrated extract rarely transfers to the food, or the other way round — these are cross-links, not equivalents.