New Bill Would Reform FDA Drug Preclusion Standard for Supplements

Representative Diana Harshbarger on September 10 introduced the Dietary Supplement Innovation Act, legislation intended to modernize the FDA's drug preclusion provision.¹ According to a news release from Harshbarger, the legislation would establish regulatory certainty, protect pharmaceutical innovation incentives, and support access to dietary supplements for consumers. It also notes that manufacturers have faced uncertainty when investigational drug filings remain undisclosed and preclusion persists indefinitely even after the underlying pharmaceutical research has been dropped.

“For decades, this broken drug preclusion process has allowed Washington bureaucrats to threaten lawful dietary supplements that have safely been purchased over the counter for years, stifling innovation and denying Americans access to products they already trust,” Representative Harshbarger stated. “My bill delivers the regulatory certainty manufacturers need to innovate and invest with confidence, while establishing transparency and predictability within the drug preclusion framework and preserving consumer access to dietary supplements.”

What Actions Does the Bill Outline?

The bill's provisions focus on 5 main actions. It would protect ingredients with a history of prior marketing, let preclusion lapse after roughly seven years of inactive drug development, give FDA discretion to authorize otherwise-precluded ingredients, require the agency to weigh factors like dosage and route of administration when determining if a drug and supplement contain the same “article,” and allow manufacturers to challenge FDA preclusion claims in court.

Bill text and a summary one-pager are available through Representative Harshbarger's congressional website.

How Has Industry Responded to the Bill?

Trade groups responded favorably and were included in the news release. Steve Mister, president and CEO of the Council for Responsible Nutrition (CRN), commended the introduction of the legislation and said the bill brings balance to a long-standing issue. “This bill doesn't weaken FDA or undermine pharmaceutical innovation,” Mister explained. “Instead, it restores the balance Congress intended when it enacted DSHEA by creating evenhanded, transparent, or predictable rules that allow both industries to innovate while protecting consumer access to safe dietary supplements.”

Scott Melville, president and CEO of the Consumer Healthcare Products Association (CHPA), highlighted the effects of the bill. “We applaud Representative Harshbarger for introducing this important legislation, which modernizes an outdated provision of law, provides much-needed regulatory certainty, and helps ensure consumer access keeps pace with innovation,” he stated.

In a separate statement, the American Herbal Products Association (AHPA) commended the introduction of the Dietary Supplement Innovation Act.² “Botanical dietary supplement innovation depends on clearly defined pathways that allow safe herbs and natural products to reach consumers,” stated Graham Rigby, AHPA President and CEO. “Representative Harshbarger's legislation would help restore the balance Congress intended under DSHEA and better ensure that drug development does not unnecessarily foreclose dietary supplement innovation. AHPA applauds Representative Harshbarger for her leadership and urges Congress to advance this important legislation as a key plank of modernizing the Federal Food, Drug, and Cosmetic Act's robust dietary supplement provisions.”

Why Has the Preclusion Clause Been a Recurring Concern for CRN?

The preclusion issue predates this bill. Speaking at SupplySide Connect New Jersey earlier this year, CRN senior vice president and general counsel Megan Olsen described the preclusion provision as effectively a "race to market" test: a supplement can remain on the market even while an ingredient is also under investigation as a drug, but once that drug is investigated or reaches market first, the supplement version must yield unless FDA issues a rule allowing it to stay.³ Because investigational new drug filings aren't always public, Olsen said, companies may unknowingly invest in ingredients that are later found precluded once an undisclosed filing surfaces.

What Did Industry Groups Tell FDA About the Scope of Dietary Ingredients?

Drug preclusion also came up in comments a coalition of associations submitted to FDA following the agency's March 2026 public meeting on the scope of dietary supplement ingredients.⁴ The Natural Products Association (NPA) pointed to FDA's disagreements over N-acetyl-L-cysteine (NAC) and nicotinamide mononucleotide (NMN) as evidence of the uncertainty the preclusion clause causes, and NPA president and CEO Daniel Fabricant stated the current system "tilts heavily in favor of pharmaceutical development." Among its recommendations, NPA had asked FDA to update its list of precluded ingredients on a regular basis and to amend IND regulations to allow limited disclosure of investigational filings, so companies do not unknowingly invest in ingredients that may already be precluded.

References

1. Congresswomen Diana Harshbarger. Harshbarger Introduces Legislation to Fix Outdated FDA Drug Preclusion Rules, Protect Access to Dietary Supplements. September 10, 2026. Accessed September 11, 2026. https://harshbarger.house.gov/media/press-releases/harshbarger-introduces-legislation-fix-outdated-fda-drug-preclusion-rules
2. American Herbal Products Association. AHPA welcomes introduction of Dietary Supplement Innovation Act. September 10, 2026. Accessed September 11, 2026. https://www.ahpa.org/blog_home.asp?display=1411
3. Saraceno N. CRN Seeks Industry Alignment on Drug Preclusion Reform to Safeguard Supplement Innovation. Nutritional Outlook. April 27, 2026. Accessed September 11, 2026. https://www.nutritionaloutlook.com/view/crn-seeks-industry-alignment-on-drug-preclusion-reform-to-safeguard-supplement-innovation 
4. Saraceno N. Industry Groups Urge FDA to Broaden Definition of Dietary Supplement Ingredients. Nutritional Outlook. May 5, 2026. Accessed September 11, 2026. https://www.nutritionaloutlook.com/view/industry-groups-urge-fda-to-broaden-definition-of-dietary-supplement-ingredients