People taking out personal pensions are being warned about the "enormous" fees being charged which can result in their savings being halved.
A report by the think tank, the RSA , says customers should receive bank account-style statements to prevent them from facing these hidden costs.
It said inappropriate personal pensions that fail to reveal taxes, stock-lending fees and broking commissions, are being sold to unsuspecting customers.
Pensions funds should learn from countries such as Denmark, where people receive an annual account, presented like a bank statement, which shows their investment savings, the report said.
In some cases an extra 2% annual charge can, over the lifetime of a pension, result in a halving of pension benefit.
The report calls for the introduction of a "statement before purchase" which would show British workers the likely effect that fees will have on their pension outcome.
Even when costs are declared, it is not done in a way in which many pension savers and small employers are likely to understand, the study said.
The Seeing Through The British Pension System report follows a previous RSA study which found that a large proportion of pensions disappear in fees - with charges swallowing up to 40% of the value of the pension over its lifetime.
The report's co-author, David Pitt Watson, said: "For markets to work effectively, consumers need to know what they are buying.
"It is extraordinary that, after so many years, such a system is not in place in this country."
Harinder Mann, who also wrote the report, said the proposals would give Britons greater confidence in the saving system.
