# iF vs Leptin

The clearest difference is update cadence: Leptin at every 4 days against iF's every 2 months. Leptin also leads on iOS requirement (15.1 vs 18.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. iF sells 12 one-off in-app purchases and Leptin sells 10 in-app purchases, starting at $9.99 per month. Whichever you choose, the download price is not the number that matters.

iF ships an update every 2 months, Leptin every 4 days. The most recent releases landed on September 22, 2026 and September 25, 2026 respectively.

## The numbers

| Metric | iF | Leptin |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 4 days** |
| Size | 45 MB | 56 MB |
| Requires iOS | 18.0 | **15.1** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Hans Babylone](https://appshunter.io/developer/1550504166) | [GRAYLIN AI (PTY) LTD](https://appshunter.io/developer/1872989548) |

## What reviewers say

### iF

[App page](https://appshunter.io/ios/app/if-interfast/id1550503953)

**In-app purchases (12)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Mediterranean Chicken | $0.99 | one-time |
| Fish Fillet in Tomatoes Garlic | $0.99 | one-time |
| Grilled Shrimp with Salsa | $0.99 | one-time |
| Salmon with Mango Salsa | $0.99 | one-time |
| Guacamole On Toast With Salad | $0.99 | one-time |
| Peppered Beef With Asparagus | $0.99 | one-time |
| Cauliflower Pizza | $0.99 | one-time |
| Chocolate Cupcake | $0.99 | one-time |
| Keto Pancake | $0.99 | one-time |
| Intermediate level | $2.99 | one-time |
| Experienced Level | $3.99 | one-time |
| Personalized & Statistics | $4.99 | one-time |


### Leptin

[App page](https://appshunter.io/ios/app/leptin/id6765621429)

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

**In-app purchases (10)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Basic Monthly | $9.99 | per month |
| Premium Monthly | $19.99 | per month |
| Unlimited Monthly | $49.99 | per month |
| Basic Yearly | $99.99 | per year |
| Premium Yearly | $199.99 | per year |
| Unlimited Yearly | $499.99 | per year |
| $10 AI Credits | $12.99 | one-time |
| $25 AI Credits | $32.99 | one-time |
| $50 AI Credits | $64.99 | one-time |
| $100 AI Credits | $129.99 | one-time |


## Frequently asked questions

### Is iF free?

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

### Is Leptin free?

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

### Do iF or Leptin have ads?

Neither iF nor Leptin shows ads.

### Which is updated more often, iF or Leptin?

iF ships an update every 2 months, and Leptin every 4 days. Most recently, iF was updated on September 22, 2026 and Leptin on September 25, 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.*