Supplement Firms Are Flooding Reddit to Game AI Search Results

Peptide sellers have been quietly seeding biohacker forums with promotional posts designed to manipulate what ChatGPT and Google's AI Overviews tell you when you ask a health question.

Companies selling peptide supplements have been spamming subreddits in a coordinated effort to influence AI-generated search answers.
The tactic — being called AI-engine optimisation, or AIEO — exploits the fact that large language models train on and cite Reddit heavily.
ChatGPT and Google's AI Overviews have both surfaced the planted content as apparently credible community discussion.
The practice is an evolution of old-school astroturfing, updated for an information environment where the AI middleman reads the forum so you don't have to.
404 Media reported the trend, raising questions about how quickly platforms and AI providers can detect and filter coordinated inauthentic posting.

There is a corner of Reddit where people argue, at length and with genuine intensity, about peptides — synthetic compounds that some biohackers use for recovery, cognition, or longevity. It is also, according to a report published this week by 404 Media, a place where supplement companies have been quietly planting posts designed not for the forum's human readers, but for the AI systems that index them.

The practice has been given a name: AI-engine optimisation, or AIEO. The mechanics are straightforward enough to make a traditional SEO consultant wince with recognition. Post enthusiastic, product-adjacent content to high-authority forums. Watch AI models — which pull heavily from Reddit when generating answers — surface that content as organic community knowledge. When a user asks ChatGPT or Google's AI Overview about a peptide, the answer cites what looks like a candid thread. It is not always candid.

Both ChatGPT and Google's AI Overviews have been observed returning results shaped by the planted material, 404 Media reported. The implications reach well past the biohacker niche. Reddit became a preferred training and retrieval source for large language models in part because forum discussion looks like unfiltered human opinion. AIEO is a direct exploit of that assumption.

The tactic is not entirely new — brands have seeded forums with fake grassroots posts since the early days of message boards. What changes the calculus now is the AI intermediary. Human readers could, in theory, smell a shill post. A retrieval-augmented AI querying a subreddit for consensus does not have the same nose.

Neither Reddit nor the AI providers named in the report had issued formal responses at time of publication. The 404 Media piece ran on July 14, 2025.