Substack's Rise in Influencer Marketing

Introduction

While everyone watched TikTok, a quieter shift happened in the inbox. Substack turned writers, journalists and experts into a new kind of influencer, ones whose audiences pay to hear from them and read every word. For marketers used to chasing fleeting feed impressions, that is a different and arguably deeper form of influence. Newsletters are back. They matter.

Here is why Substack became an influencer-marketing channel, the creators leading it, plus how brands can work with them.

Why Substack matters now

Substack influence does not look like social influence, which is exactly the point. The differences are what make it valuable.

• Paying audiences. Subscribers pay to read, a far stronger signal of attention than a free follow.
• Inbox intimacy. Long-form content delivered to an inbox builds trust a scrolling feed rarely matches.
• Qualified readers. The format attracts engaged, discerning audiences rather than passive scrollers.
• Deep niches. Newsletters thrive on specialism, from product strategy to food to culture.

The platform's scale

This is not a fringe channel anymore. By the platform's own public data, more than 3 million paid subscriptions are now active across Substack.

The habit is mainstream too: a 2025 Pew Research survey found that 41% of US adults read at least one independent newsletter every month. And the ceiling for a single creator is high. Substack's most-subscribed individual creator has reportedly passed 2.5 million subscribers, an audience comparable to a primetime television slot, built entirely through a newsletter. For marketers, that combination of scale and depth is hard to ignore.

The creators leading it

Substack is often associated with political commentary, yet the creators relevant to most brands span far wider niches.

Sources: Favikon, StarNgage, Influencers-Time, Substack public data. A selection across niches, not a ranked list; audiences vary widely.

How brands work with them

The main route is newsletter sponsorship, placing a brand message inside a trusted, high-intent inbox. Because the audience is engaged and qualified, even a modest list can outperform a much larger social following on conversions, especially for products the readers will actually use.

There is a catch worth respecting. Substack audiences are discerning, with some of the biggest creators refusing advertising entirely to stay fully subscriber-funded. So this is not a channel for spray-and-pray promotion. Partnerships work when the creator's niche genuinely fits the brand and the message honours the newsletter's voice, rather than interrupting it.

How to use this with Flinque

One honest point up front: Flinque does not cover Substack. It focuses on Instagram, YouTube, TikTok and X, so newsletter-specific deals run through Substack itself. Newsletters are their own channel with their own rules.

That said, the best newsletter creators rarely live on Substack alone. They build and promote their work across those same four platforms, where their wider audience and credibility show. For discovery and vetting there, you can use Flinque to search 10M+ verified creators by niche, run a fake follower check, then benchmark engagement. Treat Substack as one channel in a creator's mix, then find the rest where the discovery tools reach.