diff --git a/pkg/products.go b/pkg/products.go
index 263b6c3..50128c3 100644
--- a/pkg/products.go
+++ b/pkg/products.go
@@ -124,6 +124,7 @@ func HandleUpdateProduct(w http.ResponseWriter, r *http.Request, params httprout
 		return
 	}
 	if !form.Validate() {
+		w.WriteHeader(http.StatusUnprocessableEntity)
 		mustRenderEditProductForm(w, r, form)
 		return
 	}