diff --git a/src/api/routes/experiments.ts b/src/api/routes/experiments.ts
index 0cad7342c..24fd3ef1e 100644
--- a/src/api/routes/experiments.ts
+++ b/src/api/routes/experiments.ts
@@ -35,7 +35,7 @@ router.get("/", route({}), (req: Request, res: Response) => {
 	if (uniqueUsernames) {
 		// hash, revision, bucket, override, population, hash_result, as_mode
 		// bucket 4 is used by the official client, and enables live checking and suggestions, 3 is only live checking
-		data.assignments.push([2476969328, 0, 3, -1, 0, 9267, 0, 0]);
+		data.assignments.push([2476969328, 0, 4, -1, 0, 9267, 0, 0]);
 	}
 	res.send(data);
 });
diff --git a/src/api/routes/unique-username/username-attempt-unauthed.ts b/src/api/routes/unique-username/username-attempt-unauthed.ts
index a1f63a691..3af1fa883 100644
--- a/src/api/routes/unique-username/username-attempt-unauthed.ts
+++ b/src/api/routes/unique-username/username-attempt-unauthed.ts
@@ -25,7 +25,7 @@ router.post(
 		}
 
 		res.json({
-			taken: !User.isUsernameAvailable(body.username),
+			taken: !(await User.isUsernameAvailable(body.username)),
 		});
 	},
 );
diff --git a/src/api/routes/users/@me/index.ts b/src/api/routes/users/@me/index.ts
index 55d2ce122..5c3cfb29c 100644
--- a/src/api/routes/users/@me/index.ts
+++ b/src/api/routes/users/@me/index.ts
@@ -172,7 +172,7 @@ router.patch(
 				}
 
 				// check if username is already taken (pomelo only)
-				if (!User.isUsernameAvailable(body.username))
+				if (!(await User.isUsernameAvailable(body.username)))
 					throw FieldErrors({
 						username: {
 							code: "USERNAME_ALREADY_TAKEN",
diff --git a/src/util/entities/User.ts b/src/util/entities/User.ts
index 5ec9862e4..07b68b6d8 100644
--- a/src/util/entities/User.ts
+++ b/src/util/entities/User.ts
@@ -379,7 +379,7 @@ export class User extends BaseClass {
 
 		if (uniqueUsernames) {
 			// check if there is already an account with this username
-			if (!User.isUsernameAvailable(username))
+			if (!(await User.isUsernameAvailable(username)))
 				throw FieldErrors({
 					username: {
 						code: "USERNAME_ALREADY_TAKEN",
@@ -463,11 +463,14 @@ export class User extends BaseClass {
 	}
 
 	static async isUsernameAvailable(username: string) {
-		const user = await User.findOne({
-			where: { username },
-			select: ["id"],
+		// TODO: implement regex check?
+		const count = await User.count({
+			where: {
+				username: username.toLowerCase(),
+			},
 		});
-		return !user;
+
+		return count === 0;
 	}
 }