diff --git a/src/libnss.zig b/src/libnss.zig
index 6088864..e4b2464 100644
--- a/src/libnss.zig
+++ b/src/libnss.zig
@@ -11,6 +11,7 @@ const Allocator = mem.Allocator;
 const DB = @import("DB.zig");
 const File = @import("File.zig");
 const ErrCtx = @import("ErrCtx.zig");
+const compress = @import("compress.zig");
 const CGroup = @import("Group.zig").CGroup;
 const PackedGroup = @import("PackedGroup.zig");
 const CUser = @import("User.zig").CUser;
@@ -476,8 +477,13 @@ fn initgroups_dyn(
         return c.NSS_STATUS_NOTFOUND;
     };
 
-    var gids = db.userGids(user.additional_gids_offset);
-    if (size.* < gids.remaining()) {
+    // TODO: use db.userGids()
+    const offset = user.additional_gids_offset;
+    var vit = compress.varintSliceIteratorMust(db.additional_gids[offset..]);
+    const remaining = vit.remaining;
+
+    var gids = compress.deltaDecompressionIterator(&vit);
+    if (size.* < remaining) {
         const oldsize = @intCast(usize, size.*);
         const newsize = if (limit <= 0)
             oldsize + gids.remaining()