diff --git a/include/nlohmann/detail/output/output_adapters.hpp b/include/nlohmann/detail/output/output_adapters.hpp
index 1cad57b19..f2a230320 100644
--- a/include/nlohmann/detail/output/output_adapters.hpp
+++ b/include/nlohmann/detail/output/output_adapters.hpp
@@ -53,7 +53,7 @@ class output_vector_adapter : public output_adapter_protocol<CharType>
     JSON_HEDLEY_NON_NULL(2)
     void write_characters(const CharType* s, std::size_t length) override
     {
-        std::copy(s, s + length, std::back_inserter(v));
+        v.insert(v.end(), s, s + length);
     }
 
   private:
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 50e5c805c..41827a4b1 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -14247,7 +14247,7 @@ class output_vector_adapter : public output_adapter_protocol<CharType>
     JSON_HEDLEY_NON_NULL(2)
     void write_characters(const CharType* s, std::size_t length) override
     {
-        std::copy(s, s + length, std::back_inserter(v));
+        v.insert(v.end(), s, s + length);
     }
 
   private: