# KnowKnow AI vs 智慧護膝3+3

The clearest difference is in-app purchases: 智慧護膝3+3 at none against KnowKnow AI's 4. 智慧護膝3+3 also leads on iOS requirement (13.0 vs 16.4). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. KnowKnow AI sells 4 in-app purchases, starting at $9.99 per month. 智慧護膝3+3 asks for nothing beyond the download.

KnowKnow AI ships an update every 3 weeks, 智慧護膝3+3 every 2 weeks. The most recent releases landed on September 16, 2026 and September 28, 2026 respectively.

## The numbers

| Metric | KnowKnow AI | 智慧護膝3+3 |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.0 (2 ratings)](https://appshunter.io/ios/app/knowknow-ai/id6748773796/reviews)** | — |
| Number of ratings | **2** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Every 2 weeks** |
| Monetization | Freemium | — |
| Size | 104 MB | 191 MB |
| Requires iOS | 16.4 | **13.0** |
| Devices | iPhone | **iPhone, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [RETOWER TECH PTE. LTD.](https://appshunter.io/developer/1827325376) | [智遊科技服務股份有限公司](https://appshunter.io/developer/1724284475) |

## What reviewers say

### KnowKnow AI

[App page](https://appshunter.io/ios/app/knowknow-ai/id6748773796)

Effortlessly track your nutrition by simply snapping a photo of your food. This AI-powered tool provides instant analysis of calorie and macronutrient content, helping you understand your dietary intake.

**Highlights:** AI-powered food analysis, Instant calorie and macro breakdown, Photo-based tracking, Nutrition insights

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| KnowKnow Plus | $9.99 | per month |
| KnowKnow Pro | $14.99 | per month |
| KnowKnow Plus Yearly | $113.99 | per year |
| KnowKnow Pro Yearly | $178.99 | per year |


### 智慧護膝3+3

[App page](https://appshunter.io/ios/app/3-plus-3/id6761870008)

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

**In-app purchases:** none


## Frequently asked questions

### Is KnowKnow AI free?

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

### Is 智慧護膝3+3 free?

智慧護膝3+3 is free to download, with no in-app purchases.

### Do KnowKnow AI or 智慧護膝3+3 have ads?

Neither KnowKnow AI nor 智慧護膝3+3 shows ads.

### Which is updated more often, KnowKnow AI or 智慧護膝3+3?

KnowKnow AI ships an update every 3 weeks, and 智慧護膝3+3 every 2 weeks. Most recently, KnowKnow AI was updated on September 16, 2026 and 智慧護膝3+3 on September 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.*