Do Herbal Teas Contain Heavy Metals? The Facts About Contamination

December 19, 2025 •

5 min read

According to a 2013 study published in the Journal of Toxicology, some brewed teas contained lead levels considered unsafe for pregnant and lactating women. The question of do herbal teas contain heavy metals is a complex one, with contamination depending on many factors, including the plant species, growing region, and processing methods.

Quick Summary

Research indicates that herbal teas can accumulate heavy metals from contaminated soil, air, and water, though the amount that leaches into the brewed liquid is often low. Levels of contamination vary significantly depending on the specific plant, its origin, and how it is brewed.

Key Points

Contamination is Possible: Herbal teas can contain heavy metals like lead, cadmium, and aluminum, accumulated from polluted soil, water, and air.
Accumulation Varies: The level of contamination depends on factors such as the herb species, the growing location, and the age of the plant leaves.
Brewing Affects Leaching: Longer steeping times increase the amount of heavy metals that leach from the leaves into the water.
Lead Concerns for Vulnerable Groups: Some teas have shown lead levels considered unsafe for pregnant and lactating women, so caution is advised.
Minimizing Risk is Possible: Consumers can reduce heavy metal exposure by shortening brew times, using filtered water, and choosing reputable brands with clean sourcing.
Filtration Benefit: Interestingly, tea leaves themselves can filter a small amount of heavy metals from the brewing water.

The Source of Heavy Metal Contamination

Heavy metals, such as lead (Pb), cadmium (Cd), and arsenic (As), can find their way into herbal teas through several pathways. The journey from the earth to your teacup can expose herbs to environmental pollutants that affect their final composition. Understanding these sources is the first step toward informed consumption.

Environmental Factors

Industrialization, mining, automobile exhaust, and the use of certain agricultural pesticides contribute to the contamination of soil and air with heavy metals. When herbal plants are grown in these polluted environments, they absorb these metals through their roots. For example, a study examining Chinese tea plantations noted that lead (Pb) primarily comes from atmospheric deposition, with automobile emissions being a significant contributor, especially for younger leaves. This means that the location of cultivation is a critical factor in determining the potential heavy metal content of the plant.

Plant Bioaccumulation

Plants have varying capacities to absorb and accumulate heavy metals. The tea plant, Camellia sinensis, is a known "hyperaccumulator" of certain metals, including aluminum, which it stores in its leaves. This ability allows it to thrive in acidic soils, but it also means that the plant can concentrate these metals. A key finding is that older leaves tend to have higher metal loads than younger ones, simply because they have had more time to accumulate them. This has implications for products that use different parts of the plant.

Processing and Packaging

Beyond the growing environment, the manufacturing process can introduce additional heavy metals. Some studies mention contamination from rolling machines, though this can vary by factory and process. In terms of packaging, while some tea bag materials like cellulose might absorb metals, other materials, like nylon, have no such effect. The packaging itself is less of a concern for heavy metal content than the plant material inside.

What the Research Says About Heavy Metals in Herbal Tea

Multiple studies have investigated the levels of heavy metals found in brewed tea, both herbal and traditional, revealing a complex picture of risk that depends on the metal in question, the source of the tea, and the brewing method.

Studies on Lead (Pb)

A 2013 study in the Journal of Toxicology analyzed 30 commercial bagged teas, finding detectable lead in all of them. The study determined that 73% of teas steeped for 3 minutes and 83% of those steeped for 15 minutes had lead levels exceeding the safety limit for reproductive health set by California's Proposition 65. The amount of lead that leaches into the brew increases with steeping time. However, other studies note that only a fraction of the lead in dry leaves is extracted into the water, suggesting the risk from average consumption is often low.

Findings on Cadmium (Cd) and Arsenic (As)

Research has also consistently found detectable levels of cadmium and arsenic in both tea leaves and the brewed liquid. A study on heavy metal content in black teas found that cadmium and arsenic levels in the infusion increased with steeping time. While contamination rates for these metals are generally low compared to other elements, the carcinogenic risk of cadmium in certain areas has been a cause for concern. Arsenic leaching from leaves is typically low, though detectable levels remain present.

The Unique Case of Aluminum (Al)

Aluminum is a notable heavy metal found in teas, particularly in traditional teas but also in some herbal varieties. A 2013 study found that 20% of brewed teas tested exceeded recommended guidelines for aluminum, with levels significantly increasing after a 15-minute steep. While the weekly intake is often below official tolerable limits, it warrants consideration, especially for heavy tea drinkers.

How to Minimize Your Risk

Here are some practical steps you can take to reduce your exposure to heavy metals from herbal teas:

Reduce steeping time: Since leaching increases with duration, a shorter steeping time (e.g., 3 minutes) can lower the heavy metal concentration in your tea.
Choose specific tea types: Some studies suggest that teas made from younger leaves or certain processing methods may have lower heavy metal levels. Organic white teas, for instance, have been found to have lower lead content.
Use quality water: Brewing with distilled or high-quality filtered water can prevent the addition of heavy metals from your tap water supply. Interestingly, research has also shown that tea leaves themselves can act as a minor filter for heavy metals present in the brewing water.
Limit consumption during pregnancy: Given the identified risks associated with lead, limiting or avoiding tea consumption is recommended for pregnant and lactating women.
Diversify your sources: Purchasing teas from reputable companies that test for contaminants can provide peace of mind. Sourcing from regions with less industrial pollution is also beneficial, though not always clearly labeled.

Comparing Heavy Metal Leaching in Herbal vs. Traditional Tea


Feature	Herbal Tea (e.g., Mint, Chamomile)	Traditional Tea (e.g., Black, Green)
Plant Origin	Varies widely by plant species and source region; potential for high contamination if grown in polluted soil.	All from Camellia sinensis, a known hyperaccumulator of metals like aluminum.
Lead (Pb)	Levels can vary; some herbal teas showed detectable Pb.	Detectable in brewed tea; leaching increases with steep time.
Cadmium (Cd)	Found in some herbal teas, with levels dependent on plant type and origin.	Found in leaves and infusions; carcinogenic risk identified in certain areas.
Aluminum (Al)	Lower total and infusion concentrations than traditional teas in some studies.	Often higher in leaves and infusions; levels can exceed drinking water limits.
Steeping Impact	Longer steeping times can increase the leaching of metals like Pb and Cd.	Leaching also increases with steeping time, particularly for aluminum and lead.
Overall Risk	Risk is highly dependent on the specific herb and its cultivation.	Risk is influenced by the plant's inherent hyperaccumulation properties and geographic origin.

Conclusion: Navigating the Complexities of Herbal Tea Safety

The question of whether herbal teas contain heavy metals is unequivocally yes, they can. However, this does not mean every cup is a health risk. Heavy metals like lead, cadmium, and aluminum are present in many herbal and traditional teas, primarily absorbed from contaminated soil and air. While the total amount in the dry leaves can sometimes be significant, the concentration that leaches into your brewed tea is typically much lower. The risk is not uniform, varying greatly based on the herb, its growing location, and the brewing process. For example, longer steeping times increase the extraction of these elements. Awareness and proactive steps, like sourcing from reputable suppliers and limiting brew time, can effectively mitigate potential exposure. By understanding these factors, consumers can make informed choices to enjoy their tea with greater confidence.

Learn more about the risks and benefits of brewed tea from this NIH study.

Frequently Asked Questions

While it is possible for herbal tea leaves to contain heavy metals, the amount that leaches into the water is typically low. The risk of heavy metal poisoning from regular consumption is generally considered low for most people, but factors like high contamination levels in the leaves and frequent, heavy consumption can increase this risk.

Some of the most commonly studied heavy metals found in herbal teas include lead (Pb), cadmium (Cd), and aluminum (Al). Other metals like arsenic (As) and mercury (Hg) have also been detected, but often at lower levels.

Yes, research consistently shows that longer steeping times lead to a higher concentration of heavy metals in your tea infusion. To minimize exposure, consider reducing your brew time, especially with potentially high-risk herbal varieties.

Organic labeling primarily addresses pesticide use and may not guarantee lower heavy metal levels. Some studies have found comparable or even higher levels of certain heavy metals in organic versus non-organic teas, as heavy metals can be absorbed from soil regardless of organic farming practices.

To choose safer tea products, look for brands that publicly test their products for heavy metals and other contaminants. Sourcing from companies that cultivate their herbs in regions with low industrial pollution can also help minimize risk.

There is emerging research suggesting that tea leaves can naturally filter small amounts of heavy metals from the water they are brewed in. However, this is not a detoxification method and should not be relied upon to mitigate heavy metal exposure from other sources. Always prioritize clean water and minimizing consumption of contaminated products.

Due to stricter safety limits for reproductive health, some studies have found lead levels in brewed teas to be unsafe for pregnant and lactating women. It is advisable for these individuals to limit or avoid tea consumption and consult a healthcare professional.