Does Your Private Label Supplement or Skincare Product Need a Prop 65 Warning? Who Decides, What It Says and the 2025 Short-Form Rules

Short answer: Only when the product can expose people in California to a Proposition 65 chemical above its safe harbor level, and the business responsible has 10 or more employees. In a private label deal the duty sits upstream of the store: the manufacturer, supplier or distributor gives the warning on the label or in a written notice to the retailer.

Prop 65 warning: a notice California requires before a business knowingly exposes people to a chemical the state lists as causing cancer, birth defects or other reproductive harm. Exposure at or below the chemical's safe harbor level doesn't need one.

Key stats: Proposition 65 in 2026

• Over 800 chemicals are on the Proposition 65 list, first published in 1987. ^[1]
• Fewer than 10 employees: businesses this size are exempt from the warning requirements. ^[1]
• 12 months: the time businesses get to comply after a chemical is listed. ^[1]
• $2,500 per violation per day: the maximum penalty. ^[1]
• 0.5 µg per day: lead's safe harbor level for reproductive harm (MADL); its oral cancer level (NSRL) is 15 µg per day. ^[2]
• January 1, 2028: products manufactured and labeled before this date can keep the older short-form wording. ^[5]

What does Prop 65 actually require?

Proposition 65, the Safe Drinking Water and Toxic Enforcement Act of 1986, requires businesses to give "clear and reasonable" warnings before knowingly and intentionally exposing anyone to a listed chemical. ^[1][13] The California Attorney General enforces it, and so can district attorneys, some city attorneys and private individuals acting in the public interest. ^[1]

Each chemical has a safe harbor level. For chemicals that cause cancer, it's the exposure expected to cause no more than one excess case of cancer in 100,000 people (the NSRL). For chemicals that cause reproductive harm, it's the no-observable-effect level divided by 1,000 (the MADL). ^[1]

One detail private label brands miss: the warning rules treat dietary supplements as "food," so a supplement uses the food warning format, while a lotion or cleanser uses the consumer product format. ^[3]

Does your product need a warning? The 4-Question Prop 65 Check

1. 1.California exposure. Will people in California buy or use it, including through online orders? The rules count internet sellers as retail sellers. ^[3]
2. 2.Business size. Does the business responsible for the warning have 10 or more employees? Businesses with fewer than 10 are exempt. ^[1] Check each company in your supply chain, since the exemption depends on each business's size.
3. 3.Listed chemical. Can the product expose people to a listed chemical? For supplements, the usual one is lead, listed for developmental and reproductive toxicity since February 27, 1987. ^[2] Ingredients can be listed too: cocamide DEA, a coconut-derived foaming agent used in products like shampoos and hand soaps, has been listed as causing cancer since June 22, 2012. ^[6][7]
4. 4.Above safe harbor. Is the daily exposure above the safe harbor level? At or below it, no warning is needed. ^[1]

Yes to all four means two choices: reformulate (or change ingredient suppliers) or warn.

How do you estimate exposure for a supplement?

Start with the heavy-metal results on your certificate of analysis, then use this screening formula:

µg per day = ppm × grams per daily serving

The same lead result can be fine in a capsule and need a warning in a large-scoop powder. This is a screening check, not a legal exposure assessment; confirm borderline results with your testing lab or a Prop 65 attorney. Skin-applied products are harder to estimate because exposure depends on how much product is used and absorbed.

Who is responsible for the warning in a private label deal?

• Upstream businesses carry the primary duty. The "manufacturer, producer, packager, importer, supplier, or distributor" can comply by putting the warning on the product label or labeling, or by sending written notice to the retailer's authorized agent. That notice has to be renewed every year while the retailer sells the product in California. ^[4]
• Retailers place what they receive. The retail seller is responsible for placing and maintaining the warning materials it gets, including for internet sales. ^[4]
• Retailers warn on their own only in specific cases, such as selling under their own brand, knowingly adding a listed chemical, covering or altering a required label, or not posting a warning after getting notice. ^[4]

If you own the brand and sell to stores, on Amazon or on your own site, you're upstream. Agree in writing with your manufacturer who tests, who decides on and words the warning, and who notifies retailers. On wellness and aromatherapy products, PMG reviews intended claims against FDA, FTC and state-level requirements, notably California Proposition 65, before formulation. ^[8] See Wellness & Aromatherapy and Certifications & Compliance.

What does the warning have to say?

For reproductive toxicants, the wording ends "to cause birth defects or other reproductive harm." ^[5]

What changed in the 2025 short-form rules?

• Name the chemical. Short-form warnings must include at least one chemical name for each type of harm. ^[12]
• New signal words. "CA WARNING" or "CALIFORNIA WARNING" can be used in addition to "WARNING." ^[12]
• Dates. The new wording could be used from January 1, 2025. Products manufactured and labeled before January 1, 2028 can keep the older short form, such as "Cancer - www.P65Warnings.ca.gov," however long they stay on sale. ^[5][12]

If you're reprinting labels anyway, switch to the new short form now so you don't reprint again before 2028.

How do Prop 65 warnings work for online sales?

For internet purchases, the warning has to appear in one of three ways: on the product display page; through a clearly marked hyperlink using the word "WARNING," "CA WARNING" or "CALIFORNIA WARNING" on that page; or displayed prominently to the buyer before the purchase is completed. ^[10] Food warnings, including supplements, use the same list of methods. ^[11]

Printable checklist: Prop 65 before your first production run

Download the fillable checklist (PDF)

1. 1.Map where the product will sell: California stores, your own site, marketplaces.
2. 2.Confirm which businesses in your chain have 10 or more employees.
3. 3.Check every ingredient against the Proposition 65 list, which OEHHA's program publishes.
4. 4.Get heavy-metal results (lead, cadmium, arsenic, mercury) on the COA for botanicals, minerals and powders.
5. 5.Calculate daily exposure (ppm × grams per day) and compare it with the safe harbor level.
6. 6.Decide: reformulate, change ingredient supplier, or warn.
7. 7.If you warn: use the right format (food or consumer product), name the chemical, use a signal word and the right web address.
8. 8.Put it in writing: who tests, who words the warning, who notifies retailers, and who renews written notices each year.

Frequently asked questions

Glossary

• OEHHA: California's Office of Environmental Health Hazard Assessment, which administers the Proposition 65 program; the list must be updated at least once a year. ^[1]
• Listed chemical: a chemical on the Proposition 65 list as causing cancer, birth defects or other reproductive harm.
• Safe harbor level: an exposure level at or below which no warning is needed. ^[1]
• NSRL (No Significant Risk Level): the safe harbor level for carcinogens, no more than one excess cancer case in 100,000 people. ^[1]
• MADL (Maximum Allowable Dose Level): the safe harbor level for reproductive toxicants, the no-observable-effect level divided by 1,000. ^[1]
• Short-form warning: a shorter warning allowed on the product label. ^[10]
• Retail seller: a business that sells consumer products directly to consumers, including via the internet. ^[3]
• 60-day notice: the notice a private enforcer sends before filing a Prop 65 lawsuit. ^[13]

Planning a supplement or skincare launch that will sell in California? Read what has to be on a private label supplement label, or start a project with PMG.

About Product Management Group

PMG is a full-service private label manufacturing partner for skincare, nutraceuticals, supplements, personal care, and wellness brands. We handle everything from R&D and formulation through manufacturing, packaging, regulatory compliance, and fulfillment, working with FDA-registered, GMP-compliant partner facilities in Florida, North Carolina, Texas, Minnesota, and Arizona. We work with everyone from first-time founders to established retail brands, with minimums starting at 1,000 units.