Nearly nine in 10 (88%) women aged 45-54 surveyed by retirement specialist Just Group did not know they were entitled to free, independent and impartial pension guidance.
The 12% who said they were aware was nearly half the 20% of men aged 45-54 who knew about the service.
Women were also initially more sceptical than men about the value of a pension guidance session.
Under half (45%) said it would help them make sense of their retirement options, compared to 56% of men.
That rose sharply to 63% of women and 68% of men once they knew there is no cost for the service.
Research by the Pensions Policy Institute earlier this year said the average income from private pensions for women aged over 65 is £3,920 a year, £4,700 a year less than men.
Stephen Lowe, group communications director, at Just Group said: “Pension Wise should be a compelling proposition for women in particular but male users outnumber female users by three to two.
“Usually the smaller the investment, the less likely people are to seek professional support. The fact that Pension Wise is free to users should overcome that cost blockage, but that message does not seem to be getting through.
“It’s a chicken and egg situation – people who have a guidance appointment understand its value, but those who don’t know about it won’t book an appointment and find out how it can help them.”
He said that streaming pension savers into guidance by automatically booking appointments would overcome this problem by reaching groups among those most likely to miss out.
The research was conducted between 3 and 10 August 2020 on behalf of Just Group by Opinium with 1,000 UK adults aged 45-54.