Around a fifth of men and two-fifths of women aged 55 to 64 have no private pension, according to new research.
Of those that do, men with defined benefit (or final salary) pensions have built up a median pot of £235,800, almost double the £139,100 for women, according to a report by Age UK and the Financial Services Commission (FSC).
Men's defined contribution pensions are nearly three times bigger than women's, with a median pot of £23,000 and £8,100 respectively.
The report also found that half of women aged 55 to 64 with a private pension, have a fund of less than £22,000 - that would provide an annuity income of just £1,300 a year.
Looking at the professions, construction and property workers put aside the most for retirement, according to research from Aegon, with retirement income projected to pay them £14,000 a year, but this is still a vast £28,500 short of ￼their expectations.
"It's a myth that the entire generation of so-called 'baby boomers' is financially prepared for retirement," added Age UK and the FSC in their report.
"Our analysis suggests that up to 20% show very low readiness for ageing, having little or no private pension, housing wealth nor material wealth. All but the most affluent face challenges," stated the report.
Given that people aged 85 and over make up the fastest growing segment of the population and that they are "arguably the poorest served by the financial services industry", Age UK and the FSC said it's time for providers to catch up with retirees' spending patterns.
"Generally, people tend to spend more in the early, more active years of retirement, with spending decreasing in the middle years and then increasing again with additional care and medical expenses," the report explained.
Adaptable pension products
Age UK and the FSC said they would like to see products that adapt with people's actual retirement spending patterns.
"While we recognise that many won't have the luxury of a variable income, others may want a product or a suite of products that help them to meet the occasional large cost (whether expected or unexpected), whilst providing a steady income and some level of guarantee that the overall pot won't run out before they die."
They suggested a retirement product that gives a regular income with the ability to withdraw larger sums as needed.
They said this "would give an individual the certainty of a regular income, with inbuilt flexibility to manage unexpected costs. This could work in a similar way to a mortgage that allows you to overpay and withdraw overpayments without penalty".
While Age UK believes more people will look towards releasing equity from their homes to help boost their incomes in retirement, it said "confusing, restrictive and changeable product terms" - such as unpredictable exit penalties - were of concern.
It added that it would like to see innovation and improvements in equity release products.
Nigel Waterson, chairman of the Equity Release Council, said: "Equity release has witnessed significant growth of lending in the last year with some providers also announcing new flexibilities on capital and interest repayments. Continuing innovation will play an important role in boosting the uptake of equity release, and renewed interest from regulators and new entrants in the potential for product development bodes well for the future."