A lack of authenticity online appears to a major gripe among young U.S. adults and teens.
Around 69 percent said they felt their social media friends were only being themselves for a small amount of the time online, and 57 percent said they wished these people would be more authentic. 63 percent complained that they found it annoying scrolling through the "fluff" posted by their friends.
Nearly 40 percent said they didn't feel like they could be themselves online, and 36 percent said they didn't feel there existed the right platform to truly express their real selves. Just over a third said they were spending less time on social media now that their parents, aunts, uncles or older relatives were on it. Two in five said they wouldn't post something online because they thought an older relative might see it.
College students (31 percent) were more likely than high school students (23 percent) to post something online without giving it much thought. They were also more likely than high school students to de-friend people for being fake (56 percent versus 47 percent, respectively).
Read MoreChained to your smartphone? Maybe try the NoPhone
Social media fatigue
The poll follows other recent surveys which also indicate that some U.S. teenagers are falling out of love with social media.
A recent survey by research and consulting firm Kelton found that while 82 percent of U.S. teens use social media, more than half said their teen years would be better without it.
Furthermore, there is evidence that the popularity of the world's largest social network Facebook – which has 1.32 billion users worldwide – is on the decline.
Facebook use among teenagers is down to 45 percent from 72 percent from the spring to the fall of 2014, a study by the research arm of investment bank Piper Jaffray earlier this month revealed.
Read MoreInstagram passes Twitter in race for US smartphone users
But instead of shunning social media altogether, these teens seem to be turning towards other sites like Instagram, with the number of teens using the site rising to 76 percent from 69 percent over the same period, the survey found.
Young people could also be using anonymous social media sites, such as Whisper and Yik Yak, as substitutes for more public forums.
On Whisper, users post 'secrets' or random thoughts without anyone knowing who they are, and the site claims its users post 2.6 million messages a day. Meanwhile, Yik Yak, launched in November last year, allows users to make posts – known as 'yaks' – anonymously. These posts are then 'upvoted' or 'downvoted' and commented upon by other users. It is currently active at more than 1,000 colleges and universities worldwide, the Guardian reported.