Why the Biggest Advertising Agencies Are Betting on TikTok

Until a few years ago, not many insiders would have guessed that TikTok—an app most famous for 15-second dance videos and lip-sync competitions—would be at the very heart of worldwide advertising. But now, industry giants ranging from WPP and Publicis to Omnicom and Havas are making TikTok a key channel. Why? Because TikTok radically shifted human consumption of content, discovery of brands, and buying decisions.
For decades, legacy agencies had their reputations based on TV, print, and later Facebook and Google ads. But migrating audiences have made an agency pivot a necessity. TikTok is where culture originates, where trends are made, and where younger demographics spend their hours. To advertise on TikTok requires not only creativity but jugaad, cultural competence, and access to creator networks. That's why large agencies—and dedicated TikTok ads agencies—are diversifying their portfolios so TikTok marketing is a key component in their strategies.
This story reveals why the biggest agencies are betting so heavily on TikTok, what trends are behind the shift, what agencies have learned in order to succeed, and what it means for brand marketers looking to compete. Along the way, we'll look at real examples from Fenty Beauty, Duolingo, Gymshark, and e.l.f. Cosmetics which show just how transformative TikTok has become.

Platform Trends Fostering the Transition

TikTok is not only another social media platform—it transformed consumption habits for media and raised expectations for advertising. These next wave of platform trends are why international agencies doubled down.

Younger People Migration

As TikTok is increasingly the online home base for Gen Z and young millennials. According to App Annie measurement, TikTok users are now spending more time there even than on YouTube, Instagram, or Facebook. And more importantly, over 60% of TikTok users are under 30. To legacy agencies whose clients are so in need of a connection with young consumers, TikTok is a direct line in an otherwise untouchable population through either TV or even legacy social media.
For brand advertisers on TikTok, this migration of its users means not only reach but cultural relevance. As opposed to Instagram, whose content tends to feel perfected and polished, TikTok feeds on authenticity, humor, and edgy creativity. Correspondingly, agencies are shifting gears to create commercials that come naturally to the feed rather than are imposed upon it.

Vertical Video Domination

Vertical video wasn't only popularized by TikTok but perfected it. Its full-screen, scannable format has since been duplicated by YouTube Shorts and Instagram Reels. However, while imitation is akin to flattery, leaders invent. Vertical-first content is no longer a nice-to-have format but a creative necessity for agencies today.
This evolution has prompted advertising agencies to remake creative production pipelines. Even TV commercials or YouTube Adscape-style landscape ads won't do. Ads needed to come in bite size, hold attention within a three-second span, and optimize for sound-on mobile consumption. Big shops once synonymous with cinematic TV commercials are gearing up now for quick-turn, trend-facing vertical spots.

Commerce Meets Culture

The addition of TikTok Shop made it a full commerce engine. TikTok is distinctive in its combination of cultural discovery with seamless purchasing. A beauty product featured in a viral video can now be purchased immediately without leaving the app.
For agencies, this commerce-and-content combination is a goldmine. It allows agencies to create campaigns that go beyond awareness into measurable sales conversions. Today's TikTok ad agency doesn't just make impressions—it can make direct revenue, closing the entertainment-to-transaction loop.

Agency Capabilities Developed

Agencies had to rewrite their playbooks to compete with TikTok's rapid expansion. These capabilities are a requirement for success:

Trend-Skimming Creatives

TikTok operates at the pace of culture. Overnight a song, a meme or a dance craze can blow up and fade in a matter of days. Commercials agencies employed full-time TikTok strategists and creative directors whose specialty is tracking trends. That enables them to produce content based on what is trending at a moment.
For instance, when a piece of audio goes viral, agencies are in a position to translate client messaging in such a format at once—an agency authoring, approving, and publishing content within 24–48 hours. With such "trend-skimming," brands are consistently a part of the cultural conversation as opposed to playing catch-up.

Owner Network Integrations

The economy of TikTok is based on its creators. As opposed to conventional celebrity endorsements, TikTok creators provide credibility, niche expertise, and authenticity. Advanced agencies handle strong portfolios of creators and brand-influencer match-making.
A TikTok agency may identify a micro-influencer in sports fitness in promoting a sports wear brand or a beauty content creator in launching a new cosmetic product. By including creators in their campaigns, agencies are offering brands cultural credibility in addition to access to active communities.

Live Event Optimization

TikTok campaigns can’t simply be set and forgotten. Performance depends on constant adjustments to bidding, targeting, and creative execution. Top agencies now run live optimization desks, monitoring campaigns in real-time and tweaking elements as trends shift or audiences react differently than expected.
For example, if one creative is converting more 18–24-year-olds than expected, agencies can shift budget in real-time. That real-time adjustability ensures brands are always maximizing their spend, making TikTok advertising more efficient than static, offline buys.

How Agencies Win on TikTok

Fenty Beauty: Product Launch by Founders

Rihanna's Fenty Beauty based its brand on inclusivity and innovation, so its TikTok is no exception. Blending forces with influencers of mixed ethnicities and skin tones, Fenty released pieces which were immediate viral hits.
For one such initiative, a brand collaborated with creators in showing how its foundation blended for all skin tones. Apart from generating million-plus organic views, videos also elicited direct sales in TikTok Shop. Partner agencies managed such collaborations, taking care of creator relations as well as brand messaging consistency.

Duolingo: The Power of Personality

Language study app Duolingo converted its green owl brand into a TikTok sensation. Through agency guidance, Duolingo undertook an unconventional, unpolished type of content ideally suited to TikTok's personality. From humorous sketches to humorous involvement in trends, Duolingo's account has millions of followers with some of the highest rates of engagement for any brand on TikTok.
The lesson: agencies in tune with TikTok values can help brands drop their corporate sheen and become more human and empathetic.

Gymshark: When Fitness Met Virality

British fitness brand Gymshark began using TikTok early when it started collaborating with fitness influencers to showcase its clothes. Through agency expertise, Gymshark set up challenges and co-promotions which went viral throughout the app. One campaign involved asking users for their fitness transformations which helped create millions of end-user posts and catapulting brand awareness.
By collaborating with a TikTok advertising agency, Gymshark was also able to supplement those organic efforts with paid advertising so that the campaign extended past the influencer's following.

e.l.f. Cosmetics: The Billion-View Campaign

Perhaps one of the most famous TikTok case studies is e.l.f. Cosmetics' "Eyes. Lips. Face." campaign. Through an agency, the brand created a memorable original song with a challenge. Within weeks, it was one of TikTok's most viral branded campaign videos with over 5 billion views and inspiring awareness as well as sales.
The campaign established a benchmark for TikTok commercials by proving agencies were capable of attaining cultural reach at a level only hitherto reserved for commercials broadcast during the Super Bowl.

What It Reveals for the Advertisers

Higher Creative Standards

There are greater creative demands on brands. TikTok viewers disdain conventional advertising formats in preference for content entertaining first and selling second. That requires new creative thinking, with agencies assisting brands in developing TikTok-born storytelling that is organic in feel yet effective in reach.

Professionalized Metrics Tracking

Ch Chasing vanity metrics such as views and likes is so yesterday. New TikTok campaigns require advanced measurement in the form of cost per acquisition, conversion rates, click-through rates, and direct TikTok Shop sales. That's what agencies are capable of, connecting campaigns directly with business results rather than vacuous engagement.

Competitive Advantage for Young Entrepreneurs

After initially shunning TikTok, brands now enjoy first-mover benefit. TikTok specialist agencies are assisting clients in taking share-of-voice as their rivals fall further behind. As those early users of Facebook advertising in the last decade once did so dominantly, those brands and agencies who learn TikTok today are putting themselves in position for successive years of benefit.

Conclusion

TikTok is the next big destination for culture, commerce, and creativity. Largest ad agencies globally are all in on it, but it's not reserved for multinational companies. Startups or Fortune 500 businesses are partnering with a TikTok advertising agency so you can scale campaign efforts, tap into creator networks, and create measurable ROI.
Should your brand seek a way to branch out of standard media platforms and advertise on TikTok, it is now or later. Discover how effective TikTok marketing techniques can create a difference in your sale and reach by contacting The Short Media.