diff --git a/nixos/modules/security/pam_mount.nix b/nixos/modules/security/pam_mount.nix
index a17f38f93325..ad78f38b0866 100644
--- a/nixos/modules/security/pam_mount.nix
+++ b/nixos/modules/security/pam_mount.nix
@@ -167,9 +167,11 @@ in
           <!-- create mount point if not present -->
           <mkmountpoint enable="${if cfg.createMountPoints then "1" else "0"}" remove="${if cfg.removeCreatedMountPoints then "true" else "false"}" />
           <!-- specify the binaries to be called -->
-          <fusemount>${pkgs.fuse}/bin/mount.fuse %(VOLUME) %(MNTPT) -o ${concatStringsSep "," (cfg.fuseMountOptions ++ [ "%(OPTIONS)" ])}</fusemount>
+          <!-- the comma in front of the options is necessary for empty options -->
+          <fusemount>${pkgs.fuse}/bin/mount.fuse %(VOLUME) %(MNTPT) -o ,${concatStringsSep "," (cfg.fuseMountOptions ++ [ "%(OPTIONS)" ])}'</fusemount>
           <fuseumount>${pkgs.fuse}/bin/fusermount -u %(MNTPT)</fuseumount>
-          <cryptmount>${pkgs.pam_mount}/bin/mount.crypt -o ${concatStringsSep "," (cfg.cryptMountOptions ++ [ "%(OPTIONS)" ])} %(VOLUME) %(MNTPT)</cryptmount>
+          <!-- the comma in front of the options is necessary for empty options -->
+          <cryptmount>${pkgs.pam_mount}/bin/mount.crypt -o ,${concatStringsSep "," (cfg.cryptMountOptions ++ [ "%(OPTIONS)" ])} %(VOLUME) %(MNTPT)</cryptmount>
           <cryptumount>${pkgs.pam_mount}/bin/umount.crypt %(MNTPT)</cryptumount>
           <pmvarrun>${pkgs.pam_mount}/bin/pmvarrun -u %(USER) -o %(OPERATION)</pmvarrun>
           ${optionalString oflRequired "<ofl>${fake_ofl}/bin/fake_ofl %(SIGNAL) %(MNTPT)</ofl>"}