Facebook is losing appeal among teens and young adults which is contributing to generally slowing growth for the platform, according to the latest projections from research firm eMarketer.

At the same time alternative social apps Snapchat and (Facebook-owned) Instagram are seeing rising and double-digit growth in the same youth demographic — suggesting younger users are favoring newer and more visual communications platforms.

“Both platforms have found success with this demographic since they are more aligned with how they communicate — using visual content,” noted eMarketer forecasting analyst Oscar Orozco in a statement.

It’s the second consecutive year of expected usage declines for Facebook among this advertiser-coveted group, according to the researcher.

eMarketer suggests some tweens are even skipping adopting Facebook entirely (it calls them “Facebook nevers”) and going straight to the rival platforms, even as remaining tweens and teens appear less engaged on Facebook — logging in less frequently and spending less time on the platform.

While having slipping relevance among a coveted ad demographic is obviously not good news for a social behemoth whose business is dependent on ad revenue, Facebook does have the consolation of also owning one of the two main youth-friendly alternative platforms: Instagram . (Aka, ‘if you can’t be it, buy it’.)

Still, eMarketer is also projecting that the acquisition that got away from Zuck, Snapchat, will overtake Instagram and Facebook in the total teen (12 to 17) & young adult (18 to 24) ages for the first time in 2017 — boosting its share of US social network users to 40.8 per cent, and projected to push close to a majority by 2021. (Though Instagram is also forecast to maintain its greater reach through this timeframe.)

Back in 2013, when reports of Facebook’s spurned acquisition attempts of Snapchat surfaced, it followed fast on the heels of the company reporting a first-time decline in young teens using its service daily.

Nearly four years later Facebook’s problem with keeping teens happy has only got bigger — but the company’s success at using Instagram to successfully clone Snapchat’s features has helped mitigate the issue. (Even if it means Facebook’s corporate motto should really now read: ‘Move fast and clone things’.)

eMarketer couched U.S. Facebook usage in the 12 and 17 age-group as dropping the most “precipitously” — noting that while 81.9% of social network users in that age range are projected to use Facebook this year, the figure will slide to 76.2% by 2021.

Other highlights from eMarketer’s forecast:

Facebook usage in the US in the 12 to 17 age group will fall 3.4% vs 2016, to 14.5M, accelerating from the 1.2% slip seen last year

Facebook’s US monthly users overall are expected to grow 2.4% this year to 172.9M — up slightly on the prior forecast due to increased adoption by older Internet users

Snapchat’s US monthly users are expected to grow 25.8% in 2017 to 79.2M monthly, with growth figures adjusted higher for all but the oldest age group, and the biggest upward revision for the 18-to-24 group which is forecast to see usage escalate 19.2% this year

Instagram’s US monthly users are expected to grow 23.8% in 2017, up from prior forecasts, to 85.5M, expanding its user base among under 12s by 19%, and 12 to 17s by 8.8%

In the UK, Facebook is estimated to have 32.5M monthly active users this year, remaining the most popular social network, even as it also loses share to Snapchat and Instagram among younger age groups there

In the UK, Instagram is projected to have 16.7M monthly users in 2017, an increase of 34.8% over 2016 — and a total reach amounting to more than a quarter of the UK population (the same as its reach in the US)

In the UK, Snapchat is projected to have 14M monthly users, with growth of 20.2% expected this year (meaning it will reach around a fifth of the population)

While Twitter’s total UK user base is expected to be 12.6M this year

eMarketer’s methodology counts a monthly user as someone who is accessing their account at least once per month, consistently, each month throughout the calendar year. It says it bases its forecasts on analysis of quantitative and qualitative data from research firms, government agencies, media firms and public companies, along with interviews with senior execs at publishers, ad buyers and agencies.

At the time of writing Facebook had not responded to a request for comment.