A small but promising technology called transcutaneous autonomic neuromodulation (tAN) — which delivers electrical stimulation via clips placed in front of the ear canal — passed its safety test in a new phase 2a trial, but fell short of proving it can meaningfully lower blood pressure in patients with uncontrolled hypertension.

In the double-blind trial of 63 adults already on antihypertensive medications, participants self-administered 30-minute daily stimulation sessions for two weeks, then once weekly for 10 weeks. At the three-month mark, both the tAN group and the sham group saw reductions in daytime systolic BP — but the difference between them wasn't statistically significant. Adherence was excellent (100% in both arms), and no serious side effects were linked to the device.

There was one intriguing signal: patients with a baseline systolic BP of 160 mm Hg or higher saw a 12.73 mm Hg greater reduction with tAN versus sham — a finding researchers flagged as exploratory but worth pursuing.

By the Numbers:

• 63 adults with uncontrolled hypertension enrolled; mean baseline BP: 150/95 mm Hg
• tAN group: −3.15 mm Hg systolic reduction vs. −5.50 mm Hg in the sham group (not significant)
• Subgroup with baseline systolic ≥160 mm Hg: 12.73 mm Hg greater reduction with tAN (P = .003)
• Median adherence: 100% in both arms

Why it matters: While tAN didn't outperform sham treatment in the broader group, its strong safety profile and the signal in higher-risk patients keep the door open for future, better-powered trials targeting those who might benefit most.