SB 1033: California Proposes Increased Testing And Labeling Requirements For Protein Supplements

California's Senate is currently considering a bill that would create mandatory heavy metal testing and disclosure rules for protein supplement brands. SB 1033, modeled after the recent AB 899 baby food law, responds to a perception that protein powders, shakes, and bars contain elevated levels of heavy metals. The bill is co-sponsored by two activist nonprofits: Consumer Reports and Environmental Working Group.

Starting in 2027, existing California law requires brand owners of packaged prenatal multivitamin products to disclose information on the results of testing for heavy metals and to include on the packaging a link to the website where people can get information on that testing. It also requires makers of baby food to test representative samples of each product aggregate at least once per month for heavy metals, and make the testing information publicly available through their website.

The new bill extends many similar requirements to the more general category of "protein products," which the draft currently defines as a dietary supplement under federal law, or a protein supplement-based food product containing a protein concentrate or isolate (or blend), with at least five grams of protein per serving.

Why is California Considering this Bill?

The FDA regulates dietary supplements similar to how it regulates food, and subjects these products to requirements relating to good manufacturing practices and labeling standings, among other things. As the FDA has recognized, "heavy metals" like arsenic, lead, cadmium, and mercury are naturally occurring in the environment, and can also result from human pollution. Plants and animals absorb these heavy metals, generally leading to trace amounts of contamination in much of the food humans eat, along with supplements. Notably, protein supplements often rely on plants like soy and pea as the source of their protein content.

According to the Senate Committee on Health's analysis of SB 1033, significate consumption of these heavy metals has been associated with adverse health effects. The analysis notes that Consumer Reports has tested protein products over the years and found contaminant levels exceeded Prop 65 safe harbor levels in many products, in some cases containing ten times or more than what may trigger warning requirements.¹Nevertheless, the analysis observed that despite the detection of heavy metals in protein products, the presence of heavy metals does not necessarily indicate a risk, since toxicity depend on various factors. Further, a human health risk assessment from 2020 based on data from Consumer Reports and another study, suggested that the consumption of protein powder supplements contaminated with heavy metal is not actually associated with an increased risk of non-carcinogenic health effects.

SB 1033's Proposed Requirements

While the bill is still undergoing revisions, starting January 1, 2028, if enacted, SB 1033 would implement several requirements, including:

• Lot-by-Lot Testing: Manufacturers of bulk and packaged protein products sold, manufactured, delivered, held, or offered for sale in California would be required to test a representative sample of each lot of the product for heavy metals.
• Enforcement: The California Department of Health would be able to request these test results, with violations punishable as misdemeanors under California's Sherman Law.
• Public Disclosure with On-Pack Labeling: Brand owners would have to disclose product information including heavy metal testing, and a specified heavy metal testing label would be required on the packaging.
• Prohibition of Non-Complaint Sales: Lastly, the bill would bar people from selling, manufacturing, delivering, holding, or offering for sale, noncompliant protein products.

In particular, testing must be performed at a "proficient laboratory" that meets several accreditation standards, and uses sufficiently sensitive testing methods. The current requirements for qualified laboratories are somewhat vague, such as using an analytical method "at least as sensitive and specific" as the FDA method.²The ability of commercial laboratories to meet the required limit of quantitation and to also perform the mandated proficiency testing will likely limit the number of qualified laboratories available. Consequently, it is unclear whether there is adequate capacity of qualified laboratories in the U.S. to meet the increased demand of lot-by-lot protein product testing. Finding a qualified laboratory may be a challenge. SB 1033 clearly sets a higher bar for products sold in California as the required testing is more stringent than the FDA requirements by mandating lot-by-lot testing by a qualified lab with specific accreditation. SB 1033 would not replace testing required by the FDA, it would merely add a parallel California compliance layer.

To meet disclosure requirements, brand owners must make publicly available on their website the name and level of each heavy metal present in each lot of packaged protein product when the lot is tested, information from the product's supplement facts panel, and the statement "protein products that are used to supplement protein intake may contain trace levels of heavy metals based on how the ingredients are sourced." Product packaging must include a "prominent statement" reading "For information about heavy metal testing on this product" followed by a hyperlink to the website with test results.

What Comes Next?

For now, SB 1033 remains under consideration, and may be further revised. After some changes, the bill was recently approved by California's Senate Committee on Environmental Quality, and on May 14, 2025 was approved by the Committee on Appropriations. If the law is ultimately passed by the legislature and signed into law by the governor, protein supplement businesses will have until January 1, 2028, to comply with the testing and labeling requirements.

We strongly recommend that all companies that sell protein products, especially protein supplements, take steps to tighten the specifications for heavy metals in all ingredients used in protein products. Let us know if your company needs compliance assistance.

Footnotes

1. We note that lead levels triggering Proposition 65 are incredibly minute, and far lower than any other regulatory standard found worldwide. Further, Proposition 65 has a "naturally occurring" exemption that may apply to many of the products tested, meaning the levels Consumer Reports decided to test for were lower than what may be required by California law.

2. Section 110424.6, subd. (b)(2).

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