diff --git a/src/main/java/net/frozenorb/apiv3/route/emailTokens/POSTEmailTokensIdConfirm.java b/src/main/java/net/frozenorb/apiv3/route/emailTokens/POSTEmailTokensIdConfirm.java
index 08e82e1..6871bd7 100644
--- a/src/main/java/net/frozenorb/apiv3/route/emailTokens/POSTEmailTokensIdConfirm.java
+++ b/src/main/java/net/frozenorb/apiv3/route/emailTokens/POSTEmailTokensIdConfirm.java
@@ -33,6 +33,13 @@ public final class POSTEmailTokensIdConfirm implements Handler<RoutingContext> {
 			return;
 		}
 
+		User sameEmail = SyncUtils.runBlocking(v -> User.findByConfirmedEmail(user.getPendingEmail(), v));
+
+		if (sameEmail != null) {
+			ErrorUtils.respondInvalidInput(ctx, user.getPendingEmail() + " is already in use.");
+			return;
+		}
+
 		JsonObject requestBody = ctx.getBodyAsJson();
 		String password = requestBody.getString("password");