# Quell Flex vs Migraine Sentry

The clearest difference is in-app purchases: Quell Flex at none against Migraine Sentry's 2. Migraine Sentry's advantage is update cadence (every 3 days vs every 35 months). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. Migraine Sentry sells 2 in-app purchases, starting at $4.99 per month. Quell Flex asks for nothing beyond the download.

Quell Flex ships an update every 35 months, Migraine Sentry every 3 days. The most recent releases landed on October 25, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | Quell Flex | Migraine Sentry |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.5 (2 ratings)](https://appshunter.io/ios/app/migraine-sentry-forecast/id6789877577/reviews)** |
| Number of ratings | — | **2** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 35 months | **Every 3 days** |
| Monetization | — | Freemium |
| Size | 23 MB | 16 MB |
| Requires iOS | **16.6** | 17.0 |
| Devices | iPhone | **iPhone, Apple Watch** |
| Age rating | 12+ | 12+ |
| Developer | [NeuroMetrix, Inc.](https://appshunter.io/developer/972079953) | [KJC International Limited](https://appshunter.io/developer/6789877579) |

## What reviewers say

### Quell Flex

[App page](https://appshunter.io/ios/app/quell-flex/id1507976263)

**Features:** macOS Compatibility

**In-app purchases:** none


### Migraine Sentry

[App page](https://appshunter.io/ios/app/migraine-sentry-forecast/id6789877577)

This app forecasts migraine vulnerability by analyzing your personal health data, weather, and environmental factors. It provides daily and weekly outlooks, identifies personal triggers, and offers insights into effective treatments. Log migraines quickly and receive a clinical report for your doctor.

**Highlights:** Personalized migraine vulnerability forecast, Seven-day outlook based on weather and patterns, Passive health data analysis (sleep, HRV, heart rate), Personal trigger rankings, Plain-language explanation of deviations, Fast logging with Live Activity, Clinical PDF report for doctors

**Features:** Apple Watch app

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium Monthly | $4.99 | per month |
| Premium Annual | $29.99 | per year |


## Frequently asked questions

### Is Quell Flex free?

Quell Flex is free to download, with no in-app purchases.

### Is Migraine Sentry free?

Migraine Sentry is free to download, with in-app purchases available.

### Do Quell Flex or Migraine Sentry have ads?

Neither Quell Flex nor Migraine Sentry shows ads.

### Which is updated more often, Quell Flex or Migraine Sentry?

Quell Flex ships an update every 35 months, and Migraine Sentry every 3 days. Most recently, Quell Flex was updated on October 25, 2026 and Migraine Sentry on October 28, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*