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Why Refluxter has a Prop 65 warning for "California Residents Only" on its label

Updated: Jun 24

California Prop 65 and its implication for Nutritist Refluxter

Understanding California Proposition 65 and Its Implications for Dietary Supplements


California's Proposition 65, officially known as the Safe Drinking Water and Toxic Enforcement Act of 1986, is a regulation intended to protect California residents from exposure to chemicals known to cause cancer, birth defects, or other reproductive harm. While the intention behind Prop 65 is laudable, its implementation has often been criticized for being overly restrictive and causing unnecessary alarm.


One area where Prop 65 has significant implications is the labeling of dietary supplements, particularly those with naturally occurring trace elements like lead. Understanding why a Prop 65 warning on a dietary supplement label is not necessarily a cause for concern requires a closer look at the regulation itself and the context of naturally occurring lead in our everyday diet.


The Stringency of Prop 65


Prop 65 mandates that products containing any of over 900 chemicals identified by California as hazardous must carry a warning if they expose consumers to more than 0.5 micrograms (µg) of lead per day for reproductive toxicity. If a supplement exceeds this amount, Proposition 65 mandates a warning label stating, “Consuming this product can expose you to Lead, which is known to the State of California to cause birth defects or other reproductive harm. For more information go to” Alternatively, a shorter warning can be used: “Reproductive Harm –”. This threshold is incredibly low, reflecting California's approach to err on the side of caution. However, this conservative limit often leads to warnings on products that pose no significant health risk under normal consumption patterns.


Naturally Occurring Lead in Foods


It's important to note that all naturally occurring ingredients, such as botanical extracts and minerals, contain some lead. Therefore, supplements with these ingredients may have trace amounts of lead.


California’s standards for dietary supplements are much stricter than those of other scientific bodies. For instance, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) considers 3.0 mcg/kg/day to be a safe daily lead intake, equating to 210 mcg for an average adult [73rd meeting, 2011]. At this intake level, blood lead levels do not increase significantly. Thus, while international guidelines allow up to 210 mcg of lead per day, California's limit is 0.5 mcg, a 420-fold difference.


To reach an unsafe daily level of lead as defined by global standards, a 70 kg man would need to consume nearly 420 servings of a dietary supplement containing 0.5 mcg of lead per serving.

The FDA's interim reference level for lead is 8.8 mcg/day for females of childbearing age, with a 10x safety factor built in (the FDA had determined 88 mcg is the upper limit of safety, but wanted a 10x safety factor to err on the side of caution). This ensures lead intake stays well below levels associated with health risks.


One serving (2 capsules) of Refluxter contains approximately 0.28125 mcg of lead. If we had stated to take Refluxter only once a day we would not have been required to give a Prop 65 warning for California residents since we would have been well under the 0.50 mcg threshold. However, we wanted people to be aware that they can take Refluxter after every meal and before bedtime if desired. Therefore, 8 capsules of Refluxter would contain approximately 1.125 mcg of lead.


Comparing Prop 65 Thresholds to Natural Lead Intake


When comparing these naturally occurring levels of lead in various food items to the Prop 65 threshold, it becomes evident how stringent and potentially misleading the regulation can be:


Infographic showing lead in various food items
Lead in common food items


These comparisons highlight that the presence of trace amounts of lead in dietary supplements, particularly those derived from natural sources, is not unusual and often aligns with the lead levels found in everyday foods.


The Implications for Dietary Supplements


Dietary supplements, especially those made from natural ingredients, may carry Prop 65 warnings due to trace lead content. This can alarm consumers, leading them to believe that these supplements pose a significant health risk. However, it's crucial to understand that the lead levels triggering these warnings are often well within the range of what one would consume from a balanced diet.


The key takeaway is that while it's important to be aware of potential exposures to harmful substances, the lead content in dietary supplements flagged under Prop 65 is often comparable to, or even lower than, the levels found in common foods. The presence of a Prop 65 warning does not automatically imply a significant health hazard, but rather reflects California's highly precautionary regulatory stance.




California's Proposition 65 plays a vital role in informing consumers about potential chemical exposures. However, its stringent thresholds can sometimes result in warnings that may not be indicative of a real health risk. Understanding the context of naturally occurring lead in our diet can help alleviate undue concern regarding Prop 65 warnings on dietary supplements such as Nutritist Refluxter. As with any dietary consideration, moderation and informed choices are key to maintaining health and well-being.

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