The detailed study into how attitudes towards life and lifestyles change on hitting the big five-o found a large percentage feel increased pressure to look good.
One per cent of the older generation - or around 231,000 people - have opted for a nip, tuck or other procedure after hitting the landmark.
The good news for adults approaching 50 is that those who are now on the wrong side of half a century feel ten years younger mentally - and four years younger physically.
Six out of ten of the 50,000 people who took part in the SunLife Big 50 study said they were enjoying life more than ever.
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More than three quarters (78 per cent) said they no longer worry what other people thought of them.
Ian Atkinson, of SunLife, said: “While some over 50s are feeling the pressure to stay young, most don’t actually care what other people think and are happy just living their lives to the full.
“This includes making more of an effort to eat well and exercise more regularly than they did when they were younger which suggests that far from feeling ‘over the hill’, people aged 50 and over are making sure they are fitter than ever so they are free to do what they want to do.
“Some people still believe that turning 50 is something to worry about, that life slows down after that - but after conducting the UK’s biggest-ever study with 50,000 people over 50 we know that’s not the case at all: for many, life after 50 is the best time of their lives.”
The study, commissioned to launch SunLife’s Welcome to Life After 50 campaign, found most had changed their lifestyle since turning 50 by quitting smoking, eating more healthily and exercising more frequently.
Six out of ten said they began taking more notice of what they were eating while 46 per cent have started exercising more.
One fifth said they had cut down on drinking since turning 50 and one in seven had stopped smoking.
*According to the ONS there were 23, 072,619 people aged 50 and over in the UK in 2015. One per cent of this number is 230,726.