diff --git a/src/pages/api/lib/googleSheets.ts b/src/pages/api/lib/googleSheets.ts
index 38ccf98..a5fc84b 100644
--- a/src/pages/api/lib/googleSheets.ts
+++ b/src/pages/api/lib/googleSheets.ts
@@ -11,17 +11,63 @@ const auth = new google.auth.GoogleAuth({
 const sheets = google.sheets({ version: 'v4', auth });
 const SPREADSHEET_ID = import.meta.env.GOOGLE_SHEET_ID;
 
+async function emailExists(email: string): Promise<boolean> {
+  const formula = `=COUNTIF(G:G,"${email}")`;
+
+  // Escribir fórmula en celda auxiliar
+  await sheets.spreadsheets.values.update({
+    spreadsheetId: SPREADSHEET_ID,
+    range: 'DATABASE!Z1', // usa una columna libre
+    valueInputOption: 'USER_ENTERED',
+    requestBody: {
+      values: [[formula]],
+    },
+  });
+
+  // Leer resultado calculado
+  const result = await sheets.spreadsheets.values.get({
+    spreadsheetId: SPREADSHEET_ID,
+    range: 'DATABASE!Z1',
+    valueRenderOption: 'UNFORMATTED_VALUE',
+  });
+
+  const count = result.data.values?.[0]?.[0] || 0;
+
+  return Number(count) > 0;
+}
+
+
 export async function appendToSheet(values: any[]) {
   try {
+    const email = values[6]; // índice donde está el email en tu array
+
+    if (!email) {
+      throw new Error('Email requerido');
+    }
+
+    const exists = await emailExists(email);
+    if (exists) {
+      return {
+        success: false,
+        message: 'El email ya existe en la base de datos',
+      };
+    }
+
     await sheets.spreadsheets.values.append({
       spreadsheetId: SPREADSHEET_ID,
-      range: 'DATABASE!A2:H2',
+      range: 'DATABASE!A:H',
       valueInputOption: 'RAW',
       requestBody: {
         values: [values],
       },
     });
+
+    return {
+      success: true,
+      message: 'Registro guardado correctamente',
+    };
+
   } catch (error) {
     throw error;
   }
-}
\ No newline at end of file
+}