Manganese
Manganese is an essential cofactor, but dietary deficiency in humans has essentially never been documented outside experimental depletion — while manganese excess is a well-characterised neurotoxic syndrome. This is a nutrient almost nobody should be supplementing.
What the science says
- Deficiency is a non-problem; toxicity is the real one Moderate evidence
Manganese is required for mitochondrial superoxide dismutase, arginase and several glycosyltransferases, but human dietary deficiency has never been convincingly demonstrated outside controlled depletion experiments — grains, nuts, tea and legumes supply it abundantly. The clinical literature on manganese is overwhelmingly about excess, and the same transport biology that makes it essential is what makes it neurotoxic above a threshold.
- Excess causes manganism, a parkinsonian syndrome Moderate evidence
Chronic overexposure — welding fume, contaminated drinking water, long-term parenteral nutrition, liver failure — accumulates manganese in the globus pallidus and produces manganism: dystonia, bradykinesia, gait disturbance, tremor and psychiatric change. It resembles Parkinson's disease but responds poorly to levodopa, and unlike most nutrient toxicities it is often only partially reversible after exposure stops.
- Cognitive effects appear biphasic, not linear Limited evidence
Reviews of manganese exposure across the lifespan describe an inverted-U dose-response, in which both unusually low and elevated exposures associate with poorer cognitive and motor performance, most consistently in children. The studies are observational with inconsistent exposure assessment, and no supplementation trial has demonstrated cognitive benefit at any dose in anyone.
Dosage & safety
How to take it
Interactions
With medications
- tetracycline and fluoroquinolone antibiotics
Manganese chelates these antibiotics in the gut like other divalent minerals. take the antibiotic at least 2 hours before or 4-6 hours after
With other supplements
- iron
They share the DMT1 transporter — iron deficiency raises manganese absorption substantially, and high manganese can worsen iron status. correct iron deficiency before adding manganese, and do not take them at the same time
Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.
Frequently asked questions
Is a manganese supplement worth taking?
Almost certainly not. Dietary manganese deficiency has never been convincingly documented outside experiments, and tea, whole grains, nuts and legumes supply manganese abundantly.
Can too much manganese be harmful?
Yes. Chronic manganese excess can cause manganism, a Parkinson-like syndrome with tremor, gait problems and psychiatric changes that is often only partly reversible.
How much manganese per day is too much?
The adult upper limit for manganese is 11 mg/day, against an adequate intake of 2.3 mg/day for men and 1.8 mg/day for women. Tea plus a multivitamin plus a bone formula can add up quickly.
Who should avoid manganese supplements?
Anyone with liver disease, because manganese leaves the body mainly through bile, so manganese supplementation is contraindicated. Iron-deficient people also absorb disproportionately more manganese.
Scientific references
Where to buy
Solgar, Chelated Manganese, 100 Tablets (8 mg per Tablet)
Ships to 180+ countries · welcome discount for new customers
Referral link — this site may earn a commission on purchases.
Related in Vitamins & minerals
- Vitamin A (Retinol) Moderate evidence
- Vitamin B1 (Thiamine) Moderate evidence
- Vitamin B5 (Pantothenic Acid) Limited evidence
- Vitamin B6 (Pyridoxine) Moderate evidence
- Vitamin K1 Limited evidence
- Calcium Moderate evidence