At Least 2 Weaknesses in the Current Evidence

• Industry funding: The JUUL2 actual-use study (Goldenson et al., 2025) and the Vuse LTTS study were both funded by the manufacturers whose products were tested. While both were peer-reviewed and used rigorous methodologies, sponsorship effects are a legitimate concern. Independent replication is needed.
• Short follow-up periods: The JUUL2 study followed participants for only six weeks. The cardiovascular review noted that "longer-term studies are needed to establish the effects of individual products." Six-week switching rates may not translate to sustained cessation at 6 or 12 months.
• Observational design: The cohort studies and South Korean population studies are observational — they can show association, not causation. Participants who choose menthol may differ systematically from those who choose tobacco flavor (e.g., greater motivation to quit, different smoking histories).
• Dual use reporting gap: Per the Duke study, most e-cigarette trials don't even report dual use, making it difficult to assess whether reported "switching" represents genuine abstinence or continued low-level smoking.
• Switching definitions vary: "Past-7-day abstinence" and "past-30-day abstinence" are different measures. The FDA presented switching rates as ranges without specifying the basis, making precise comparison difficult.
• Youth appeal trade-off: Even if menthol helps adults switch, the FDA explicitly acknowledged youth appeal as a risk. The public health calculus depends on whether the adult benefit outweighs the youth risk — and that calculation may differ by product, market, and enforcement context.