# Respiratory Sys vs Action Potentials

The clearest difference is price: Action Potentials at Free against Respiratory Sys's $2.99. Action Potentials also leads on update cadence (every 3 weeks vs every 28 months). On ads, in-app purchases, device support and iOS requirement there is nothing between them.

Action Potentials is free to download; Respiratory Sys costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Respiratory Sys ships an update every 28 months, Action Potentials every 3 weeks. The most recent releases landed on October 15, 2026 and October 11, 2026 respectively.

## The numbers

| Metric | Respiratory Sys | Action Potentials |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | — | **[4.7 (13 ratings)](https://appshunter.io/ios/app/action-potentials/id1527893283/reviews)** |
| Number of ratings | — | **13** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 28 months | **Every 3 weeks** |
| Monetization | — | Free |
| Size | 264 MB | 1 MB |
| Requires iOS | **12.0** | 13.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [VIRTUAL FILAMENTS PRIVATE LIMITED](https://appshunter.io/developer/1474217212) | [Beau Forest](https://appshunter.io/developer/1527893285) |

## What reviewers say

### Respiratory Sys

[App page](https://appshunter.io/ios/app/respiratory-sys-edutech-era/id1482237314)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Action Potentials

[App page](https://appshunter.io/ios/app/action-potentials/id1527893283)

Explore the mechanics of action potentials in real-time. Adjust parameters and introduce various drugs to observe their impact on neuronal signaling. Choose between single event simulations or continuous manual current injections.

**Highlights:** Real-time action potential visualization, Adjustable simulation parameters, Drug effect simulation (lidocaine, tetrodotoxin, TEA), Single action potential mode, Continuous manual current injection

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Respiratory Sys free?

Respiratory Sys costs $2.99, with no in-app purchases.

### Is Action Potentials free?

Action Potentials is free to download, with no in-app purchases.

### Do Respiratory Sys or Action Potentials have ads?

Neither Respiratory Sys nor Action Potentials shows ads.

### Which is updated more often, Respiratory Sys or Action Potentials?

Respiratory Sys ships an update every 28 months, and Action Potentials every 3 weeks. Most recently, Respiratory Sys was updated on October 15, 2026 and Action Potentials on October 11, 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.*