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Manganese Side Effects & Safety

Evidence:Moderate
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This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

Safety Profile

Overall safety rating: Safe with Caution

Potential Side Effects

  • Generally well-tolerated at dietary levels
  • Headache and insomnia at higher supplemental doses
  • Neurotoxicity with chronic high-dose exposure (>11mg/day) — manganism resembles Parkinson's disease
  • People with liver disease are at increased risk of manganese toxicity due to impaired biliary excretion

Drug & Supplement Interactions

  • Iron supplements compete for the same absorption transporter (DMT-1)
  • Calcium and phosphorus may reduce manganese absorption
  • Antacids and PPIs may alter manganese absorption
  • Quinolone and tetracycline antibiotics — manganese can reduce their absorption

Maximum Dose

Do not exceed: 11mg/day (NIH UL); excess manganese is neurotoxic

Full Manganese Guide

References

  1. RCTStrause L, Saltman P, Smith KT, Bracker M, Andon MB (1994). Spinal bone loss in postmenopausal women supplemented with calcium and trace minerals. Journal of Nutrition. DOI PubMed
  2. O'Neal SL, Zheng W (2015). Manganese toxicity upon overexposure: a decade in review. Current Environmental Health Reports. DOI PubMed
  3. Meta-analysisGebretsadik GG, Yang B, Glenn AJ, Yang AM, et al. (2026). Dietary manganese, type 2 diabetes, and cardiovascular disease: A UK Biobank cohort study and meta-analysis of over 270,000 individuals.. The journal of nutrition, health & aging. DOI PubMed
  4. Meta-analysisVlasak T, Dujlovic T, Barth A (2023). Manganese exposure and cognitive performance: A meta-analytical approach.. Environmental pollution (Barking, Essex : 1987). DOI PubMed
  5. Sun Y, Zhang Y (2023). Blood manganese level and gestational diabetes mellitus: a systematic review and meta-analysis.. Journal of obstetrics and gynaecology : the journal of the Institute of Obstetrics and Gynaecology. DOI PubMed
  6. Meta-analysisWong MMH, Chan KY, Lo K (2022). Manganese Exposure and Metabolic Syndrome: A Systematic Review and Meta-Analysis.. Nutrients. DOI PubMed
  7. Meta-analysisRuiz-Azcona L, Fernández-Olmo I, Expósito A, Markiv B, et al. (2021). Impact of Environmental Airborne Manganese Exposure on Cognitive and Motor Functions in Adults: A Systematic Review and Meta-Analysis.. International journal of environmental research and public health. DOI PubMed
Show 3 more references
  1. Liu W, Xin Y, Li Q, Shang Y, et al. (2020). Biomarkers of environmental manganese exposure and associations with childhood neurodevelopment: a systematic review and meta-analysis.. Environmental health : a global access science source. DOI PubMed
  2. Chen XB, Wei YH, Chen XK, Zhong J, et al. (2019). Manganese levels and hepatocellular carcinoma: A systematic review and meta-analysis based on Asian cohort.. Medicine. DOI PubMed
  3. Du K, Liu MY, Pan YZ, Zhong X, et al. (2018). Association of circulating manganese levels with Parkinson's disease: A meta-analysis.. Neuroscience letters. DOI PubMed