Losses in poorly performing Roth IRAs aren’t deductible by account owners. That’s because the investments are owned by the Roth and not the holder of the account. So like gains, losses inside the Roth are ignored for tax purposes.
You might be able to claim losses after cashing in all of your Roth IRAs. This includes closing all Roths in which you have gains as well as those with losses. If the total recovered is less than your tax basis in the accounts, then the loss is treated as a miscellaneous itemized deduction subject to the 2%-of-AGI offset.