diff --git a/src/services/subscription/subscription-router.ts b/src/services/subscription/subscription-router.ts
index e8b7a5f..e83e69c 100644
--- a/src/services/subscription/subscription-router.ts
+++ b/src/services/subscription/subscription-router.ts
@@ -14,7 +14,7 @@ subscriptionRouter.post("/", async (req, res, next) => {
         // Upsert the user info into the corresponding Subscription collection
         await Database.SUBSCRIPTIONS.findOneAndUpdate(
             { mailingList: subscriptionData.mailingList },
-            { $push: { subscriptions: subscriptionData.email } },
+            { $addToSet: { subscriptions: subscriptionData.email } },
             { upsert: true, new: true }
         );
         return res.status(StatusCodes.CREATED).json(subscriptionData);