The Financial Conduct Authority (FCA) found advised drawdown clients are paying more average charges in four out of seven providers, when compared to how much consumers who aren't advised are having to pay.
When looking at the difference in the size of pot for each category of customers, the regulator's data shows, however, that charges for advised clients are slightly greater.
The findings are part of the regulator's Retirement Outcome Review final report published today (28 June) alongside a package of measures to improve the way people fund their retirement.
The watchdog is also planning to force providers to offer their customers easy to access ready-made drawdown investment products – however, a charge cap wasn't proposed at this point.
For consumers making regular withdrawals from a pot of £50,000 or more, the difference in fees is 0.3 percentage points higher, the greatest difference between the several customers groups analysed.
The lowest gap – 0.13 percentage points – is for clients not making regular withdrawals from a pot of £50,000 or less.
The regulator warned, however, that its analysis doesn't account for the use of products by advised consumers that could be different and therefore more costly for providers.
FTAdviser contacted several providers to clarify this difference in charges.
Alistair McQueen, head of savings and retirement at Aviva, argued it would be misguided to read the regulator’s data as relating to the core drawdown charges.
He said: "Aviva’s non-advised and advised pension drawdown products are not the same, so we are not comparing like with like.
"The markets are also different, driving different competitive prices.
"Regardless, there is little difference in core product charges, ranging from 0 to 0.4 per cent for non-advised, and from 0.1 to 0.4 per cent for the advised product.
"Charge differences depend upon the size of pension fund, as is common practice."
Steve Webb, director of policy at Royal London and former pensions minister, explained where savers choose a drawdown product with the aid of an adviser, it is more likely that they will choose a more sophisticated product with a slightly higher charge.
He said: "As always, the key question is not cost but value-for-money. If people are taking good advice and choosing a more tailored product that meets their individual needs, then this may well lead to a better outcome despite the slightly higher cost.
"This is one reason why an across-the-board charge cap would be difficult to apply to drawdown without limiting the choices open to investors."
At Aegon, non-advised drawdown is only available to existing customers who specifically request it.
A spokesperson at the provider said that charges are the same for both advised and non-advised customers.
Scottish Widows has been approached for comment.
Aberdeen Standard Life declined to comment on this specific data at this time.
Andrew Macintyre, chartered financial planner at Alan Steel Asset Management, wasn't surprised by the regulator's findings.
He said: "Although the paper does suggest that while mean charges on advised drawdown are higher, there is not a clear pattern.