Overview
- A peer‑reviewed paper published June 15–16, 2026, reported that menthol and synthetic coolants in e‑cigarette aerosols caused more premature heartbeats and altered heart‑rate measures in mice and changed electrophysiology in hormonally stressed lab‑grown human heart cells.
- The compound WS‑23 produced the largest effect in mice, roughly tripling the number of premature beats when added to nicotine aerosols compared with nicotine alone.
- Researchers linked the effects to activation of the TRPM8 cold receptor, which creates a smooth, cooling sensation that can deepen or increase inhalation and also triggers heart and stress‑hormone responses in the models used.
- The study has clear limits: it used only male mice and isolated human cardiomyocytes, so it cannot by itself prove real‑world risk in women, people with heart disease, or long‑term outcomes in humans.
- Sales of cooling‑flavored products have surged in recent years while many policies exempt mentholic or cooling additives, so authors and external experts say regulators should reassess coolant levels and fund human studies to define public health risk.