Can Petralex Hearing Aid App be used as hearing aids?

If you or someone close to you struggles to follow conversations or the TV, a free hearing aid app such as Petralex can look like an easy first step. The Petralex hearing aid app, available for Android and iOS, turns a smartphone and ordinary earphones into a sound amplifier: it runs an in-app hearing test, builds a profile for each ear and amplifies the sound picked up by the phone or headset microphone. Its website says it has more than 5 million users. What matters more is what independent research and the app's own fine print say. Petralex describes itself as a personal sound amplification product (PSAP), not a certified medical device and not an FDA-classified OTC hearing aid, and its hearing test is meant only for adjusting the app. In the largest clinical trial of the app, it made soft sounds louder but did not improve word recognition or hearing in noise compared with a conventional hearing aid. This guide explains what Petralex can and cannot do, how reliable its hearing test is, what it costs, how to download and set it up, and when a professional hearing evaluation is the better first step.

The Petralex hearing aid app offers several features aimed at people with hearing difficulties: an in-app hearing test for each ear, amplification of up to about 30 dB with dynamic compression, four amplification formulas, left/right balance, noise reduction and a live speech-to-text transcriber. Clinical studies from Seoul National University Hospital found it the best of the apps they compared, but still clearly behind a basic hearing aid.

• The app uses the phone's or headset's microphone to pick up sound, processes it according to your profile and plays it back through wired or Bluetooth earphones. You can create profiles for different places, such as home, a café or a lecture room, and use the phone as a remote microphone placed near a TV or speaker.
• The free version includes the hearing test, per-ear correction, compression, four sound modes, the transcriber and Bluetooth support. A Premium subscription adds Super Boost (up to 1000% amplification), stronger noise suppression, unlimited profiles, a recorder, a tinnitus mode and a 4-week adaptation course.
• On the App Store the app is rated 4.2 from about 2,100 ratings; the developer cites 4.5 on Google Play from over 15,500 reviews. Users praise the TV and remote-microphone uses and the free tier. Common complaints include Bluetooth delay and echo, feedback whistling, update bugs and subscription cost.
• Petralex is not a hearing aid. Its own FAQ says it is not intended to compensate for hearing impairment, and its disclaimer says the hearing test does not replace a professional evaluation.
• Overall, Petralex is a low-cost way to amplify sound in quiet settings and for TV. It is not a substitute for properly fitted hearing aids.

Overall verdict: Petralex offers more hearing-oriented controls than most free amplifier apps. People with persistent hearing difficulties should still start with a professional hearing evaluation.

Overall verdict: Petralex can make some sounds louder, especially in quiet places. It is not a medically approved hearing aid, and for everyday communication purpose-built OTC or prescription hearing aids perform better.

Overall verdict: Use the Petralex test only to tune the app. Anyone with persistent or sudden hearing changes should see an audiologist or doctor.

Petralex is free to download, with optional Premium subscriptions, which makes it far cheaper than hearing aids. The lower price reflects a different category of product: an amplifier app without professional fitting, clinical validation or hearing-aid regulation.

The basic app is a free download on the App Store and Google Play, with no registration or ads, according to the developer. Premium prices on the US App Store (October 2026) include:

Several prices appear for the same period, likely reflecting different offers; check the app before subscribing. Uninstalling the app does not cancel a subscription.

Prices are approximate US ranges. You also need earphones; wired models give the lowest delay.

Why Petralex cannot replace hearing aids

• Not a medical device: the developer states it is not certified and not an OTC hearing aid.
• Limited speech benefit: no average word-recognition gain in the 2023 trial.
• No help in noise: worse than unaided in some clinical noise tests.
• Daily routine: you must carry the phone, wear earphones and keep the app running.
• Loudness risk: Super Boost (up to 1000%) can push sound to unsafe levels; the trial authors flagged this risk for amplifier apps.
• No professional support: no fitting, follow-up or real-ear verification.

Overall verdict: Petralex is worth trying as a free, low-risk amplifier for TV or quiet conversations. For diagnosed or suspected hearing loss, OTC or prescription hearing aids, chosen after a hearing evaluation, offer far more reliable help.

Overall verdict: Petralex is a clever use of smartphone audio, and it can help in quiet places. Its dependence on generic phones and earphones is also why its results are less consistent than those of a fitted hearing aid.

Overall verdict: Petralex is easy to get and free to try, but it is not a regulated hearing aid. People with hearing loss should consider FDA-regulated OTC hearing aids or professionally fitted prescription devices.

• Petralex can amplify sound and adjust it to a self-test, but it cannot reliably replace devices designed to compensate for hearing loss. In the 2023 trial, a basic Oticon hearing aid outperformed Petralex in mid-to-high-frequency gain, word recognition and hearing in noise, and scored higher on satisfaction questionnaires.
• Medical hearing aids amplify specific frequencies according to a measured hearing loss, with verified fitting, speech-focused processing, directional microphones and feedback management, and they sit in the ear all day without a phone in hand. Petralex relies on the phone's microphone, generic earphones and a home test.
• In the US, OTC hearing aids are for adults with perceived mild-to-moderate loss, while prescription devices cover a broader range with professional programming and follow-up. Petralex sits outside both categories.

First released in 2014 and updated as recently as October 2026 (version 3.4.4 on iOS), Petralex is one of the longest-running hearing amplifier apps and one of the few studied in clinical research. It is a capable free amplifier for quiet settings, but the evidence does not support using it in place of hearing aids.

• What works. The free tier is genuinely usable: per-ear hearing test, four fitting formulas, compression, remote listening, a transcriber and Bluetooth support, with no account needed. Among apps tested by Seoul researchers, it gave the best word-recognition result in a small pilot and the best noise reduction in a separate 2019 test.
• What the trials show. In the 2023 randomized trial with 38 adults, Petralex made soft sounds audible and improved a satisfaction score over no device, but did not improve average word recognition and did worse than no device in some noise tests. An Italian study (Martinez-Beneyto et al., 2020) found improved tone and word scores with the app in a sound booth, and 61% of participants rated its sound good or excellent.
• What frustrates users. Bluetooth delay and echo, feedback whistling, results that change with every phone and headset, occasional bugs after updates and a confusing set of subscription prices.
• Marketing vs. fine print. The homepage says no hearing aids are needed and lists the 2023 trial under "Recognition," yet that trial favored the hearing aid, and the FAQ says the app is not intended to compensate for hearing impairment. Readers should weigh the fine print.
• Verdict. Petralex is worth trying, especially free, for TV and quiet conversations or while waiting for a hearing appointment. It is not a clinical hearing test and not a hearing aid.

Petralex competes with free and paid amplifier apps such as Google Sound Amplifier (Android), EarMachine, Fennex and Jacoti, and with Apple's built-in Live Listen. Its main differences are cross-platform availability, a per-ear hearing test with selectable fitting formulas, and published clinical data.

• Petralex vs Google Sound Amplifier. Sound Amplifier is free from Google and simple to use. In the 7-person Seoul pilot, it gave no word-recognition improvement, while Petralex gave a small gain. Neither improved hearing in noise.
• Petralex vs EarMachine. EarMachine (free, iOS in that study) gave only a slight improvement in the same pilot. Researchers chose Petralex for their larger trial because it ran on both platforms and performed best.
• Petralex vs Fennex. In de Sousa et al.'s 2019 tests, Petralex and Fennex on an iPhone showed the shortest latency and highest noise-reduction benefit; all apps performed worse on the Android phone tested.
• Petralex vs Apple Live Listen. Live Listen is built into iOS and streams the iPhone microphone to AirPods or compatible hearing devices, without a hearing test or fitting formulas. It suits remote-microphone use; Petralex adds personalization.

None of these apps is a regulated hearing aid; the AirPods Pro hearing aid feature, covered below, is the exception in the earbud category.

Petralex runs on most current phones and works with almost any earphones, but the choice of earphones has a large effect on delay and sound.

• Wired or Bluetooth? The developer recommends wired earphones for the lowest delay. Bluetooth works, including with AirPods, but adds latency and possible echo, and some Android phones limit microphone access over Bluetooth.
• Which earphones? Studies used the earphones bundled with each phone. Researchers noted that bundled earphones may lack high-frequency output, and better earphones can extend it. Whichever you use, run the hearing test again with that headset.

Petralex works with AirPods, but if you own AirPods Pro 2 or AirPods Pro 3 and an iPhone, Apple's built-in Hearing Aid feature is a different class of product. The FDA authorized it in September 2024 as OTC hearing-aid software for adults with perceived mild-to-moderate hearing loss, and it is paired with Apple's Hearing Test. Petralex, by contrast, is a PSAP that is not intended to compensate for hearing impairment. It runs on more devices, including Android phones, wired earphones and older AirPods, and adds remote listening, a transcriber and selectable fitting formulas.

For iPhone users with AirPods Pro and perceived mild-to-moderate loss, the regulated Apple feature is the stronger choice. Petralex remains an option for Android users or people without compatible earbuds.

Setting up Petralex takes a few minutes. Use the earphones you plan to wear, and do the test somewhere quiet.

1. Download the app. Get the free Petralex hearing aid app from the App Store (iOS 13+) or Google Play (Android 5+), using the links on petralex.pro. Avoid unofficial APK or Chrome-extension downloads.
2. Connect your earphones. Wired earphones give the lowest delay; Bluetooth earphones and AirPods also work.
3. Set a safe maximum volume. The app asks you to set this before testing. Keep it at a comfortable level.
4. Run the hearing test. Respond to each tone in each ear; you can go back on mistakes or skip an ear.
5. Choose a formula. Try NAL, Berger, POGO and Petralex to see which sounds clearest.
6. Pick the microphone. Use the headset microphone for conversations near you, or the phone's microphone placed near a TV or speaker.
7. Create profiles. Make separate profiles for home, TV, cafés or lectures, each tested with the headset you use there.
8. Turn on feedback suppression if you hear whistling.

If you buy Premium, note the plan and renewal date; cancel through your App Store or Google Play subscriptions, since deleting the app does not cancel it.