diff --git a/htdocs/product/class/product.class.php b/htdocs/product/class/product.class.php
index a4f60d48dcd..a4b2f5524de 100644
--- a/htdocs/product/class/product.class.php
+++ b/htdocs/product/class/product.class.php
@@ -1025,12 +1025,13 @@ class Product extends CommonObject
             $sql .= ", accountancy_code_sell= '".$this->db->escape($this->accountancy_code_sell)."'";
             $sql .= ", accountancy_code_sell_intra= '".$this->db->escape($this->accountancy_code_sell_intra)."'";
             $sql .= ", accountancy_code_sell_export= '".$this->db->escape($this->accountancy_code_sell_export)."'";
-            $sql .= ", desiredstock = ".((isset($this->desiredstock) && $this->desiredstock != '') ? (int) $this->desiredstock : "null");
+            $sql .= ", desiredstock = ".((isset($this->desiredstock) && is_numeric($this->desiredstock)) ? (int) $this->desiredstock : "null");
             $sql .= ", cost_price = ".($this->cost_price != '' ? $this->db->escape($this->cost_price) : 'null');
             $sql .= ", fk_unit= ".(!$this->fk_unit ? 'NULL' : (int) $this->fk_unit);
             $sql .= ", price_autogen = ".(!$this->price_autogen ? 0 : 1);
             $sql .= ", fk_price_expression = ".($this->fk_price_expression != 0 ? (int) $this->fk_price_expression : 'NULL');
             $sql .= ", fk_user_modif = ".($user->id > 0 ? $user->id : 'NULL');
+
             // stock field is not here because it is a denormalized value from product_stock.
             $sql .= " WHERE rowid = ".$id;