Not only this, but 15 percent also believe they are smiling less frequently now than at any other point in their lives.
Factors such as ageing (37 percent), rising cost of living and money worries (36 percent), and reduced social interaction (34 percent), are behind the low confidence levels and smiling less.
And a staggering 90 percent of those struggling with confidence said this has impacted their ability to enjoy landmark moments – like weddings, getting a new job offer, birthdays, and attending social occasions.
The study was commissioned by Colgate as part of its #BeUltra campaign, which aims to help adults feel the best version of themselves.
As part of the initiative, the oral hygiene brand enlisted TV personality and confidence expert, Paul C Brunson, to share his top confidence boosting tips.
The Married at First Sight star said: “As the research shows, it’s never been more important for people to feel their best.
“It’s time to get the nation smiling again – and I’m excited to help do just that.”
The study also found one in three (34 percent) wish they smiled more – but a lack of self-esteem about their grin is holding them back.
Nearly two-thirds (59 percent) admitted they’d be inclined to smile more often if they felt more self-confident than they currently do.
And 35 percent believe having a whiter smile would boost their levels of self-belief.
The study, carried out through OnePoll, revealed the top moments those polled wish they could feel like the best version of themselves – including when making big life decisions (27 percent), and when starting a new job (27 percent).
Other instances when they especially want to feel great include when going on holiday (26 percent), and when attending reunions (25 percent).
