According to the provider, which polled more than 1,000 UK adults aged 50 plus, nearly two million people are set to retire many years later than planned or with less income than they anticipated, due to changes made by the government to the state pension.
For many years, the age at which individuals could claim state pension benefits was 65 for men and 60 for women.
But under the Pensions Act 2011, women's state pension age started increase more quickly to 65 between April 2016 and November 2018, with the exact date depending on the month they were born.
The research found two thirds (66 per cent) of people aged 50 plus are aware of the changes being made to equalise state pension age, with more than one in four of them having altered their retirement plans as a result.
But the impact is starker for women than men.
Only one in five men have changed their plans, but more than one in three women are doing so.
Importantly, the shift is also hitting women much more acutely in terms of how much they are altering their plans, Retirement Advantage said.
Nearly one in three women who are changing their plans say they will retire six to 10 years later than they planned – more than double the proportion of men doing so.
Additionally, one in five women say they will retire with less income than they had planned to, compared with one in seven men.
In contrast, 69 per cent of men who are changing their plans think they will retire one to five years later, compared with 55 per cent of women.
According to Andrew Tully, pensions technical director at Retirement Advantage, the research findings "make clear the significant impact the changes to the state pension age are having on retirement plans".
He said: "It is also clear the equalisation of state pension age is changing women's plans to a greater degree than men.
"Many over 50s are telling us they have heard there are changes to state pension ages but don't know the details.
"It is important that everybody approaching retirement requests a state pension forecast and consults a professional financial adviser to get a better idea of how the changes may affect them. Getting advice now is one of the best ways of ensuring your retirement plans stay on track."
Paul Gibson, managing director of Granite Financial Planning, said that his financial planning clients are well aware of the changes to state pension age.
He said: "While we include the state pension in our planning there is a recognition that things can and will change especially as people are living longer and the costs are increasing each year.
"Most of our new clients have never inquired about their state pension so we help them do this as part of our process."
More changes in the state pension age are expected in future years, at the same rate for men and women.
From December 2018, it will start to increase to reach 66 by October 2020. Between 2026 and 2028, it will increase again to 67.
In July, the DWP decided the increase in the state pension age should be brought forward to 68 between 2037 and 2039 because of increases in life expectancy.
The change will leave 7.6 million people £10,000 worse off, according to analysis by the House of Commons Library.
maria.espadinha@ft.com
