The honest answer is that some of the effect of any tinnitus app — including HushOS — is placebo, attention and the simple value of doing something rather than feeling stuck. Pretending otherwise would be dishonest. But the underlying therapies have varying levels of independent evidence, and the better apps are reasonable delivery vehicles for them.
Three of the four therapies HushOS uses have peer-reviewed clinical trial support: notched music therapy (Okamoto et al., PNAS 2010), acoustic coordinated reset (multiple Tass-group studies, mixed results), and structured CBT for tinnitus distress (Cima et al., recommended by NICE as first-line). Long-term partial-masking sound enrichment is supported by the Jastreboff TRT framework. None of these are miracle cures, and the effect sizes are moderate at best.
Where apps go wrong is when they overpromise — total silence in 7 days, a guaranteed cure, a custom AI tone. Be sceptical of that. Where they get it right is when they make it easy to do the unglamorous daily work — listen, reframe, track — that real therapy demands.
Use the app, but also see a real clinician.