🧠 Introduction
AI humanizers are tools designed to rewrite AI-generated text so it sounds natural and human-written. As AI detection tools continue to appear across schools, workplaces, and publishing platforms, demand for these tools has grown significantly.
Several AI humanizers now claim millions of users on their landing pages. While these numbers are self-reported, they offer insight into which platforms operate at the largest scale when compared with traffic, visibility, and overall market presence.
This article reviews the largest AI humanizers on the market, based on the user numbers they publicly display and how credible those claims appear relative to their reach.
📊 Claimed User Numbers Overview
The table below summarizes the user counts each platform displays on its website or marketing pages.
| Rank | Tool | Claimed Users | Likely | Notes |
|---|---|---|---|---|
| 1 | Undetectable AI | 20+ million | Yes | Strong search visibility and long domain history |
| 2 | TwainGPT | 2.3+ million | Yes | Consistent social media presence and high engagement |
| 3 | Phrasly | 2+ million | Yes | Ongoing paid search presence and steady traffic |
| 4 | StealthGPT | 1.2+ million | Yes | Active paid advertising and consistent online visibility |
These figures are not independently verified, but they align with each platform’s visibility and overall footprint.
ℹ️ Scope & Methodology Note
This list includes only AI humanizers whose primary product is rewriting AI-generated text to sound human and bypass AI detectors.
Platforms like Grammarly and QuillBot are larger overall, but AI humanization is only a small part of their broader writing and editing toolsets, so they are not included here.
Additionally, this article focuses on claimed user numbers that appear believable based on public indicators such as traffic, search visibility, advertising presence, and brand recognition.
Some smaller tools claim extremely large user counts, such as tools reporting 10+ million users or 2+ million users without corresponding traffic or visibility. In these cases, the claims do not align with observable market presence and were excluded from this analysis.
The platforms listed below represent the largest AI humanizers with user claims that align with their market presence.
🥇 Undetectable AI
Overview
Undetectable AI is the largest AI humanizer currently operating at scale. Its landing page prominently claims 20+ million users, making it the most widely adopted tool in this category.
The platform has been active longer than most competitors and appears frequently in search results, reviews, and online discussions.
Core Features
Undetectable AI focuses on high-volume rewriting and includes:
- AI text humanization
- Built-in AI detection
- Additional text transformation tools
The platform is designed primarily for speed and scale rather than fine-grained customization.
Credibility of User Claims
Given its long domain history, strong organic search presence, and widespread recognition, Undetectable AI’s claimed user count appears reasonable.
Best Fit
Undetectable AI is best suited for users who want a widely known tool with broad adoption and large-scale availability.
🥈 TwainGPT
Overview
TwainGPT claims 2.3+ million users, a figure displayed directly on its landing page.
Despite having a smaller claimed user base than Undetectable AI, TwainGPT has built a strong reputation through consistent performance and visibility.
Core Features
TwainGPT offers an integrated platform that includes:
- AI Humanizer
- AI Detector
- Writing Generator
This setup allows users to generate text, humanize it, and verify detection results within a single workflow.
Credibility of User Claims
TwainGPT’s user numbers appear believable due to its strong social media presence, steady growth, and frequent mentions across reviews and forums. Its visibility aligns well with the scale of adoption it claims.
Best Fit
TwainGPT is ideal for students, professionals, and writers who need a consistent AI humanizer that reliably bypasses AI detectors in one platform.
🥉 Phrasly
Overview
Phrasly publicly states that it has 2+ million users. The platform is an AI humanizer intended to rewrite AI-generated text and bypass AI detection, although its landing pages primarily emphasize writing assistance and academic use cases rather than detection avoidance.
This difference reflects how the product is marketed, not how it functions. In practice, Phrasly operates as a full AI humanizer while maintaining more neutral language on its public-facing pages.
Core Features
Phrasly includes:
- AI rewriting and humanization
- AI detection tools
- Writing generation tools
While the platform presents itself as a general writing assistant, its feature set clearly aligns with AI humanization and detection bypass use cases.
Credibility of User Claims
Phrasly’s claimed user base appears reasonable given its steady traffic, active paid advertising, and sustained visibility across search and writing-related platforms.
Best Fit
Phrasly is best for users who want AI-generated text rewritten to sound more natural and readable, without relying on aggressive AI detector bypassing.
🟦 StealthGPT
Overview
StealthGPT is an AI humanizer that focuses on rewriting and generating AI content in a way that sounds more natural. The platform claims to have over 1.2+ million users, which appears to be based on a live counter displayed on its site rather than a fixed published figure.
While it is unclear how this counter is calculated or how closely it reflects active usage, StealthGPT has maintained a steady presence and is commonly referenced among AI rewriting tools.
Core Features
StealthGPT includes:
- AI text rewriting and humanization
- AI content generation for essays and longer-form writing
- Utility tools such as PDF chat, SEO writing, and browser extensions
The platform emphasizes speed and convenience, offering multiple tools without heavy configuration or advanced writing controls.
Credibility of User Claims
StealthGPT displays a live user counter rather than a fixed published figure, which makes the exact methodology unclear. However, its sustained advertising activity, recognizable branding, and continued visibility suggest a legitimate and active user base.
Best Fit
StealthGPT is best for users who want a straightforward AI humanizer with additional content generation tools and a simple, fast workflow.
🏆 Best AI Humanizer Overall
While Undetectable AI leads in total claimed users, TwainGPT stands out as the best AI humanizer on the market based on actual detection results rather than scale alone.
Across repeated testing, TwainGPT consistently bypasses every major AI detector, including GPTZero, Turnitin, ZeroGPT, Copyleaks, QuillBot, and others.
Unlike many platforms that succeed on some detectors but fail on others, TwainGPT’s humanized output remains consistently undetected.
This performance advantage is independent of user count. Even with fewer claimed users than Undetectable AI, TwainGPT delivers stronger results for users whose primary goal is bypassing AI detection.
🔍 Comparing the Platforms
Scale and Reach
- Undetectable AI operates at the largest scale
- TwainGPT and Phrasly follow with similar mid-range adoption
- StealthGPT remains smaller but well established
Feature Depth
- TwainGPT is the best overall AI humanizer
- Phrasly focuses on making AI writing sound more natural
- Undetectable AI and StealthGPT prioritize speed
Transparency
- TwainGPT is the most transparent overall
- Phrasly provides documentation but has less clear pricing
- Undetectable AI and StealthGPT rely more on trials or unusual billing models
📌 Final Thoughts
A small number of AI humanizers dominate the market in terms of visibility and adoption. Based on the user numbers displayed on their landing pages and the credibility of those claims, the largest platforms include:
- Undetectable AI
- TwainGPT
- Phrasly
- StealthGPT
While Undetectable AI leads by scale, TwainGPT is the best AI humanizer overall, consistently bypassing AI detectors while producing natural, human-sounding text.
Each platform serves a different type of user, but all represent the most established options currently available in the AI humanization space.