Fifth and Ninth Circuits Diverge on FDA Vape Rule Validity

Executive summary

The U.S. Court of Appeals for the Fifth Circuit and the Ninth Circuit have reached opposing conclusions on whether the FDA can enforce its vape product rule using comparative efficacy as a regulatory standard. The Fifth Circuit upheld the rule, while the Ninth Circuit struck it down, citing procedural and substantive concerns. This divergence creates a direct conflict in federal circuit law, increasing the likelihood of Supreme Court review and introducing uncertainty into the regulatory landscape for e-cigarettes and nicotine delivery systems.

Regulatory impact: A circuit split on a core FDA authority issue may force the Supreme Court to resolve the question of whether comparative efficacy is a valid basis for product approval or denial.

What happened

The dispute centers on the FDA’s 2024 final rule under the Family Smoking Prevention and Tobacco Control Act, which requires manufacturers to demonstrate that their new tobacco products are “appropriate for the protection of public health” — a standard that includes evaluating comparative efficacy against combustible cigarettes. The rule was challenged by industry groups and trade associations arguing that the FDA exceeded its statutory authority by imposing a requirement not explicitly mandated by Congress.

The Fifth Circuit, in a 2-1 decision, affirmed the FDA’s authority to use comparative efficacy as a substantive criterion. The court held that the phrase “appropriate for the protection of public health” grants the FDA broad discretion to consider how a product compares to existing alternatives, particularly in reducing harm among adult smokers transitioning from combustible cigarettes.

Conversely, the Ninth Circuit ruled that the FDA’s reliance on comparative efficacy constituted an impermissible substantive rulemaking without proper notice-and-comment procedures. The panel concluded that defining what constitutes “appropriate” based on relative harm reduction amounts to a substantive policy decision that must be subject to formal rulemaking, which the agency did not conduct.

Why it matters

This legal split represents a fundamental clash over the scope of administrative power within the FDA’s tobacco program. If comparative efficacy becomes a binding standard, it would shift the burden onto manufacturers to prove their products reduce harm more effectively than traditional cigarettes—potentially limiting market access for newer or less studied devices.

Conversely, if the Ninth Circuit’s interpretation prevails, the FDA may lose a key tool for promoting harm reduction strategies, undermining efforts to transition adult smokers away from combustible products. The outcome will influence not only product approvals but also investment decisions, innovation pathways, and long-term public health strategy.

Market impact

The uncertainty created by the circuit split is already affecting product development timelines and investment flows. Companies with next-generation nicotine delivery systems—especially those targeting adult smokers seeking alternatives—are delaying submissions to the FDA pending clarity on the legal status of comparative efficacy.

Smaller innovators, lacking the legal and financial resources to navigate multiple appeals, face disproportionate risk. Meanwhile, larger firms are preparing contingency plans, including potential shifts toward international markets where regulatory frameworks are more stable or less litigious.

For retailers and distributors, the lack of clear guidance increases compliance risk. Products approved under one circuit’s interpretation may be deemed non-compliant under another, complicating inventory management and supply chain planning across state lines.

Regulatory impact

The split undermines the uniformity of federal regulation and raises questions about the legitimacy of the FDA’s current framework for evaluating new tobacco products. It highlights a growing tension between the agency’s public health mandate and judicial scrutiny of administrative overreach.

If the Supreme Court takes up the case, it may clarify whether the FDA can use comparative efficacy as a standalone criterion or must rely on other metrics such as safety, addictiveness, or youth appeal. The decision could also set precedent on when agencies can implement substantive rules through informal processes.

Market impact: Regulatory ambiguity is slowing product innovation and deterring investment in harm-reduction technologies, particularly among startups reliant on predictable approval pathways.

Who is affected

• Manufacturers: Especially those developing novel nicotine delivery systems, pod mods, and heat-not-burn devices.
• Regulatory consultants and legal teams: Facing increased demand for cross-jurisdictional compliance advice.
• Retailers and distributors: Operating in states covered by both circuits face inconsistent enforcement risks.
• Public health advocates: Divided on whether strict efficacy standards promote harm reduction or stifle innovation.
• Investors: Reassessing risk profiles in the vaping technology sector due to prolonged litigation exposure.

Dawsen Take

The Fifth and Ninth Circuit split reflects deeper institutional friction between executive branch regulatory ambition and judicial restraint. While the FDA aims to accelerate the transition from combustible to reduced-risk products, courts are demanding greater procedural rigor. The outcome will determine whether the agency can act proactively on public health grounds or must wait for legislative mandates.

For now, the market operates under a patchwork of interpretations. This instability favors established players with legal capacity to litigate, while disadvantaging smaller innovators who depend on timely, predictable regulatory outcomes.

What to watch

Key developments to monitor include:

• Whether the Supreme Court grants certiorari to resolve the circuit split.
• Any proposed legislative action to clarify the FDA’s authority over comparative efficacy.
• Changes in FDA submission patterns or internal guidance following the rulings.
• State-level responses, especially in jurisdictions with strong harm-reduction policies.
• International regulatory alignment, as foreign markets may interpret the split as a sign of U.S. regulatory instability.

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Original source: Fifth, Ninth Circuits Split on FDA Vape Rule