diff --git a/CHANGELOG.md b/CHANGELOG.md
index e19efb172c..280df46ba5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- fix: Serialize the default user keys in setUser #926
+
 ## 1.4.5
 
 - fix: Fix Native Wrapper not checking enableNative setting #919
diff --git a/src/js/wrapper.ts b/src/js/wrapper.ts
index 16a3d9cbc1..208745368c 100644
--- a/src/js/wrapper.ts
+++ b/src/js/wrapper.ts
@@ -166,12 +166,12 @@ export const NATIVE = {
     let otherUserKeys = null;
     if (user) {
       const { id, ip_address, email, username, ...otherKeys } = user;
-      defaultUserKeys = {
+      defaultUserKeys = this._serializeObject({
         email,
         id,
         ip_address,
         username,
-      };
+      });
       otherUserKeys = this._serializeObject(otherKeys);
     }
 
diff --git a/test/wrapper.test.ts b/test/wrapper.test.ts
index b912645581..ef67cd4b5f 100644
--- a/test/wrapper.test.ts
+++ b/test/wrapper.test.ts
@@ -21,6 +21,9 @@ jest.mock(
         nativeClientAvailable: true,
         nativeTransport: true,
         sendEvent: jest.fn(() => Promise.resolve()),
+        setUser: jest.fn(() => {
+          return;
+        }),
         startWithOptions: jest.fn((options) => Promise.resolve(options))
       }
     },
@@ -177,6 +180,29 @@ describe("Tests Native Wrapper", () => {
     });
   });
 
+  describe("setUser", () => {
+    test("serializes all user object keys", async () => {
+      const RN = require("react-native");
+
+      NATIVE.setUser({
+        email: "hello@sentry.io",
+        // @ts-ignore
+        id: 3.14159265359,
+        unique: 123,
+      });
+      // tslint:disable-next-line: no-unsafe-any
+      expect(RN.NativeModules.RNSentry.setUser).toBeCalledWith(
+        {
+          email: "hello@sentry.io",
+          id: "3.14159265359",
+        },
+        {
+          unique: "123",
+        }
+      );
+    });
+  });
+
   describe("isNativeClientAvailable", () => {
     test("checks if native client is available", () => {
       expect(NATIVE.isNativeClientAvailable()).toBe(true);