How much manganese is the upper limit?

November 24, 2025 •

4 min read

According to the National Institutes of Health, the Tolerable Upper Intake Level (UL) for manganese in adults is 11 mg per day. Understanding precisely how much manganese is the upper limit is crucial for preventing potential health problems, especially for individuals taking supplements or with pre-existing conditions.

Quick Summary

The Tolerable Upper Intake Level for manganese is 11 mg daily for adults. Risks of toxicity are low from diet alone but increase with supplements, occupational exposure, or underlying liver issues.

Key Points

Adult Upper Limit: The Tolerable Upper Intake Level (UL) for adults is 11 mg per day from all sources, including food and supplements.
Dietary Intake is Safe: Toxicity from consuming manganese through food is extremely uncommon in healthy individuals due to the body's effective regulation.
Primary Toxicity Risk: The most significant risk for toxicity comes from occupational inhalation of manganese dust or from severely contaminated water.
High-Risk Groups: Individuals with chronic liver disease and iron-deficiency anemia are more susceptible to manganese toxicity and should be cautious.
Neurological Symptoms: Severe toxicity can lead to manganism, a neurological disorder with symptoms mimicking Parkinson's disease, such as tremors and gait issues.
Varying Limits: Upper limits for children and adolescents are lower than for adults and are based on body weight.

The Official Tolerable Upper Intake Level (UL)

For healthy adults aged 19 years and older, the Tolerable Upper Intake Level (UL) for total daily manganese intake from all sources (food, water, and supplements) is 11 mg. The UL is defined as the maximum daily intake unlikely to cause harmful health effects in the general population. For most people, consuming manganese solely from a balanced diet is very unlikely to cause toxicity.

Upper Limits for Other Age Groups

Different age groups have distinct ULs for manganese, primarily extrapolated from the adult values based on body weight.

Adults (≥19 years): 11 mg/day
Pregnant and Lactating Women (≥19 years): 11 mg/day
Adolescents (14–18 years): 9 mg/day
Pregnant and Lactating Adolescents (14–18 years): 9 mg/day
Children (9–13 years): 6 mg/day
Children (4–8 years): 3 mg/day
Children (1–3 years): 2 mg/day
Infants (0–12 months): No UL established; source of intake should be from food and formula only

These guidelines are designed to protect individuals from excessive intake. It's important to note that the UL for manganese does not apply to individuals receiving high supplemental doses under medical supervision for specific conditions.

What Causes Manganese Toxicity?

Manganese toxicity, or manganism, is a rare but serious condition that primarily affects the central nervous system, leading to permanent neurological damage. The vast majority of documented cases result from non-dietary exposure, such as occupational inhalation of manganese dust or consumption of heavily contaminated drinking water.

Inhalation vs. Dietary Intake

There is a critical difference in how the body processes manganese depending on the route of exposure. When manganese is ingested from food, the liver is highly effective at regulating its absorption and excreting any excess into bile. This natural defense mechanism prevents harmful levels from accumulating in the body. However, when manganese is inhaled, it can bypass this regulatory system and travel directly to the brain, increasing the risk of neurotoxicity. This is why industrial workers, like welders and miners, face a higher occupational risk.

Risk Factors for Toxicity

While diet alone is unlikely to cause toxicity in healthy individuals, certain factors can increase the risk of adverse effects from excess intake:

Chronic Liver Disease: The liver's crucial role in regulating manganese means that individuals with impaired liver function are more susceptible to buildup and toxicity.
Iron-Deficiency Anemia: Manganese and iron share similar absorption pathways. When iron stores are low, the body increases manganese absorption, heightening the risk of toxicity if excess manganese is present.
Supplemental Manganese: Taking dietary supplements containing manganese can push a person's total intake above the UL, increasing the risk of side effects. It is vital to use supplements only as recommended and under medical guidance.

Signs and Symptoms of Manganese Toxicity

Symptoms of manganese toxicity, particularly from inhalation exposure, can develop over months or years and often present as neurological and psychiatric issues. Early psychiatric symptoms can include irritability, aggression, and hallucinations. As the condition progresses, it can manifest with symptoms similar to Parkinson's disease, including:

Tremors and muscle spasms
Difficulty walking and gait abnormalities
Poor balance and coordination
Slowed movement and rigidity
Speech disturbances, such as slurring
Headaches and insomnia
Depression and changes in mood

Identifying Foods High in Manganese

Most people can meet their manganese needs through a varied diet. The highest dietary intakes are typically seen in vegetarians and tea drinkers, though these levels are generally considered safe.

Rich sources include:
- Shellfish: Mussels, clams, and oysters
- Whole Grains: Brown rice, oatmeal, and whole-wheat bread
- Nuts: Hazelnuts and pecans
- Legumes: Soybeans, chickpeas, and lentils
- Leafy Greens: Spinach and kale
- Tea: Black tea
- Certain Fruits: Pineapple and blueberries

Manganese Intake Comparison

This table highlights the difference between typical dietary intake and the Tolerable Upper Intake Level (UL) for adults.


Type of Intake	Description	Typical Intake for Adults	UL for Adults (≥19 years)
Adequate Intake (AI)	The recommended daily intake for sufficiency.	Men: 2.3 mg/day Women: 1.8 mg/day	N/A
Dietary Intake (95th Percentile)	An estimate of high dietary intake from food sources.	Up to 6.3 mg/day (for men 31–50)	N/A
Supplemental Intake (95th Percentile)	An estimate of high intake from supplements.	Approximately 5 mg/day (adults ≥19)	N/A
Total Intake	The combined intake from all sources (diet, supplements, water).	Highly variable	11 mg/day

Conclusion

For most healthy adults, consuming a varied and balanced diet that includes manganese-rich foods is the safest way to ensure adequate intake without reaching the upper limit. The 11 mg/day Tolerable Upper Intake Level for adults is set with a wide safety margin, and toxicity from dietary sources is extremely rare. The primary concern for manganese toxicity lies with occupational exposure via inhalation or, less commonly, very high intake from contaminated water or unregulated supplements. Individuals with liver disease or iron-deficiency anemia should be particularly cautious with their manganese intake and consult a healthcare provider for personalized guidance. For those considering supplementation, adhering to the established ULs is crucial to prevent adverse neurological effects.

For more detailed information, consult the NIH Office of Dietary Supplements factsheet.

Frequently Asked Questions

The Tolerable Upper Intake Level (UL) for manganese is 11 mg per day for all adults aged 19 and over, including pregnant and lactating women in this age range.

It is highly unlikely for a healthy person to reach a toxic level of manganese from food alone. The liver effectively regulates manganese absorption and excretes excess amounts.

The primary causes of manganese toxicity are prolonged inhalation of manganese dust, such as in mining or welding, or consuming water with unusually high manganese levels. Supplementation can also cause toxicity if not properly managed.

Symptoms of severe manganese toxicity include neurological issues similar to Parkinson's disease, such as tremors, muscle spasms, and gait abnormalities. Psychiatric symptoms like irritability and depression can also occur.

Individuals with chronic liver disease and those with iron-deficiency anemia are at a higher risk of manganese toxicity. Liver disease impairs the body's ability to excrete manganese, and iron deficiency increases its absorption.

Manganese can be found in high concentrations in many foods, including whole grains, nuts (hazelnuts, pecans), legumes (chickpeas, lentils), leafy green vegetables (spinach), certain fruits (pineapple, blueberries), and shellfish.

Manganese supplements are considered likely safe for adults when taken at doses up to the 11 mg daily UL. However, taking higher doses or prolonged use can be unsafe and may cause adverse effects.