How is zinc excreted from the body?

November 29, 2025 •

3 min read

According to the National Institutes of Health, over 90% of all zinc eliminated from the body is excreted through the feces. This process is the body's primary method for controlling zinc levels and preventing toxicity, in addition to managing how is zinc excreted from the body via other routes like urine and sweat.

Quick Summary

The body regulates its zinc balance mainly through a finely tuned excretion process. Endogenous zinc is secreted into the intestine via pancreatic and intestinal secretions, with most of it exiting through feces. The kidneys play a minor role, with additional trace amounts lost through sweat, hair, and menstrual fluids.

Key Points

Primary Excretion Route: Most zinc (over 90%) is excreted via feces, mainly from endogenous pancreatic and intestinal secretions.
Homeostatic Control: The body regulates zinc levels by adjusting intestinal absorption and fecal excretion in response to dietary intake.
Role of the Pancreas: The pancreas secretes zinc-rich digestive juices into the intestine, which is a major component of the zinc pool destined for fecal elimination.
Minor Excretion Routes: Smaller amounts of zinc are also lost through urine, sweat, shed skin and hair, and other minor routes.
Excess Zinc Management: Ingesting high levels of zinc triggers an increase in fecal excretion to prevent toxicity, though supplementation with certain minerals can be necessary.
Regulation by Transporters and Proteins: The process is governed by specific protein transporters and intracellular buffers like metallothionein (MT) that manage zinc distribution and buffering within cells.
Factors Influencing Excretion: Fecal excretion can be impacted by diet (e.g., phytate content), while urinary excretion can increase with certain diseases or very high zinc exposure.

The Primary Pathway: Fecal Excretion

For the vast majority of zinc, the journey out of the body ends in the feces. This process is far more significant than other routes, accounting for over 90% of total zinc elimination in healthy individuals. This is achieved through the gastrointestinal tract in a multi-step process involving an important loop called enteropancreatic circulation.

The role of the pancreas and intestine

Secretion into the gut: The pancreas, which contains a high concentration of zinc, releases large volumes of pancreatic juice into the intestinal lumen after each meal. This secretion is rich in zinc and forms a common pool with the zinc ingested from food.
Reabsorption and excretion: Within the intestine, a portion of this endogenous zinc is reabsorbed. The rest, along with any unabsorbed dietary zinc, continues through the digestive tract and is excreted in the feces.
Homeostatic regulation: When dietary zinc intake is low, the body increases its reabsorption of this endogenously secreted zinc to conserve the mineral. Conversely, in the case of zinc excess, endogenous excretion into the feces is enhanced, helping to clear the body of the surplus.

The Secondary Pathway: Renal and Other Excretions

While fecal excretion is the main route, a smaller fraction of zinc is also eliminated through other physiological processes.

Urinary excretion: Less than 10% of the body's zinc is typically lost through urine. This route of excretion becomes more significant during certain pathological states, such as with liver disease, or when consuming pharmacological doses of zinc. Healthy adults consuming normal diets excrete only about 0.5 mg of zinc in their urine daily.
Sweat: A variable amount of zinc is lost through sweat, and this can increase significantly with strenuous exercise or in hot, humid environments. Athletes or individuals who sweat profusely may need to pay closer attention to their zinc intake to compensate for these losses.
Other routes: Smaller, more incidental routes of excretion include the loss of hair and skin cells (desquamation), semen, and menstrual blood. While minor individually, these losses contribute to the overall zinc balance over time.

Comparison of Zinc Excretion Routes


Feature	Fecal Excretion	Urinary Excretion	Sweat and Other Losses
Primary Organ(s)	Intestines, Pancreas	Kidneys	Skin, Hair, Reproductive Organs
Regulation	Highly regulated; increases with high intake and decreases with low intake.	Modest role; only significantly increased with high intake or certain disease states.	Not consciously regulated; dependent on physical activity and environmental conditions.
Typical Daily Output	Varies, but over 90% of total excretion.	Less than 10% of total zinc losses (~0.5 mg daily).	Minor, but variable. Approximately 0.5-0.7 mg per day under normal conditions.
Factors Affecting Output	Diet composition (e.g., phytate), zinc status, intestinal health.	Hydration, systemic illness (e.g., liver disease, diabetes), high doses of supplements.	Exercise intensity, ambient temperature.

The Mechanisms of Homeostasis

The body maintains a tight control over its zinc levels through a process known as homeostasis. When zinc intake is high, the intestine reduces absorption, and at the same time, the excretion via the feces increases. This dual action helps prevent the accumulation of potentially toxic levels of the mineral. In contrast, when intake is low, absorption efficiency is upregulated, and endogenous fecal excretion is reduced to conserve the limited supply.

The role of metallothionein

One of the key players in cellular zinc homeostasis is a protein called metallothionein (MT).

MT acts as an intracellular buffer, binding excess zinc within cells and preventing it from becoming toxic.
When zinc levels are high, the expression of MT is increased, leading to more zinc sequestration.
While it primarily regulates intracellular zinc, this action is part of the larger homeostatic system that influences absorption and excretion.

Conclusion

In summary, the vast majority of zinc is excreted from the body through the feces, driven by the secretion of endogenous zinc into the intestine by the pancreas and other digestive organs. This primary pathway is supplemented by minor losses through urine, sweat, and other routes. The entire process is regulated by a complex homeostatic system that adjusts absorption and endogenous excretion based on the body's overall zinc status. By prioritizing fecal elimination, the body effectively manages its mineral balance and prevents excess zinc from accumulating.

For more information on the broader context of zinc metabolism, absorption, and dietary factors influencing its bioavailability, the National Institutes of Health provides comprehensive resources on zinc.

Frequently Asked Questions

The main way the body gets rid of zinc is through fecal excretion. Endogenous zinc is secreted into the intestine primarily by the pancreas, and most of this is then eliminated through the feces.

Yes, some zinc is lost through urine, but this is a minor excretion route, typically accounting for less than 10% of total zinc losses. Urinary excretion can increase with high zinc intake or certain medical conditions.

Yes, excessive zinc intake can overwhelm the body's normal homeostatic mechanisms. While fecal excretion will increase, high levels can interfere with the absorption of other minerals, like copper, potentially leading to deficiencies.

The body does not have a dedicated storage compartment for zinc in the conventional sense. Homeostasis is maintained mainly by adjusting absorption and excretion, although zinc is present in many tissues and some (like bone) may release it slowly during deficiency.

The intestines play a central role in zinc excretion by being the final destination for most of the zinc that leaves the body. This includes both unabsorbed dietary zinc and endogenous zinc secreted from the pancreas and intestinal lining.

High-fiber foods, especially those high in phytates (like grains and legumes), can bind zinc in the intestine, forming insoluble complexes. This prevents zinc from being absorbed and instead leads to its excretion in the feces.

Sweating is a minor route for zinc loss during normal activity, but it can become more significant during strenuous exercise or in hot climates. Athletes or individuals with high sweat output might need to adjust their zinc intake to compensate for these increased losses.