Tried & Graded

Does the HAVN hat do anything?

The claims, what is known, and a blinded experiment anyone can run.

Open experimentNot yet tested — no completed runs as of 2026-10-22

Claim under test, in HAVN’s own words — not verified by us:

“Its WaveStopper fabric blocks over 99.7% of RF from phones, Wi-Fi and Bluetooth, and it improves sleep and cognition.”

How it is tested
Part one measures the radio signal reaching the head with a meter — no hat, a plain beanie, the HAVN hat. Part two is 12 nights, blinded, against an identical-looking plain beanie, with the outcome fixed in advance and a guess at which hat was which before unblinding.
Who pays
Nobody with a stake — independent, no affiliate link on the product under test.
Run it yourself on HiveJournal →

What is known today

Two different claims, two different questions

The shielding claim is physics, and testable at home. Silver-mesh fabric can block radio signals; the question is how much, at which frequencies, and whether a hat that leaves the neck and face open changes what reaches the head. The figures in circulation — 99% in one press release, 99.7% in a listing, a per-frequency table in a review — trace back to the company; the test labs are described only as “military-grade”, and we found no named, independent report.

The sleep and cognition claim is a health claim, and it has no controlled study that we could find — only customer reviews. A plain beanie feels the same on your head, which is exactly why part two is blinded against one.

What we will and won’t do

  • We won’t say it works or doesn’t until results exist.
  • We don’t link to the hat with an affiliate tag — earning from a product we are testing would be a conflict.
  • When runs come in, this page will show them, failures included.