diff --git a/include/spdlog/async_logger.h b/include/spdlog/async_logger.h
index 932d7fb3..4b538f10 100644
--- a/include/spdlog/async_logger.h
+++ b/include/spdlog/async_logger.h
@@ -58,7 +58,7 @@ public:
     std::shared_ptr<logger> clone(std::string new_name) override;
 
 protected:
-    void sink_it_(details::log_msg &msg) override;
+    void sink_it_(const details::log_msg &msg) override;
     void flush_() override;
 
     void backend_log_(const details::log_msg &incoming_log_msg);
diff --git a/include/spdlog/details/async_logger_impl.h b/include/spdlog/details/async_logger_impl.h
index 55df4313..9c4d7616 100644
--- a/include/spdlog/details/async_logger_impl.h
+++ b/include/spdlog/details/async_logger_impl.h
@@ -36,14 +36,14 @@ inline spdlog::async_logger::async_logger(
 }
 
 // send the log message to the thread pool
-inline void spdlog::async_logger::sink_it_(details::log_msg &msg)
+inline void spdlog::async_logger::sink_it_(const details::log_msg &msg)
 {
 #if defined(SPDLOG_ENABLE_MESSAGE_COUNTER)
     incr_msg_counter_(msg);
 #endif
     if (auto pool_ptr = thread_pool_.lock())
     {
-        pool_ptr->post_log(shared_from_this(), std::move(msg), overflow_policy_);
+        pool_ptr->post_log(shared_from_this(), msg, overflow_policy_);
     }
     else
     {
diff --git a/include/spdlog/details/logger_impl.h b/include/spdlog/details/logger_impl.h
index f812c025..d790d919 100644
--- a/include/spdlog/details/logger_impl.h
+++ b/include/spdlog/details/logger_impl.h
@@ -296,7 +296,7 @@ inline bool spdlog::logger::should_log(spdlog::level::level_enum msg_level) cons
 // protected virtual called at end of each user log call (if enabled) by the
 // line_logger
 //
-inline void spdlog::logger::sink_it_(details::log_msg &msg)
+inline void spdlog::logger::sink_it_(const details::log_msg &msg)
 {
 #if defined(SPDLOG_ENABLE_MESSAGE_COUNTER)
     incr_msg_counter_(msg);
diff --git a/include/spdlog/details/thread_pool.h b/include/spdlog/details/thread_pool.h
index b7eb6caa..09d8d71c 100644
--- a/include/spdlog/details/thread_pool.h
+++ b/include/spdlog/details/thread_pool.h
@@ -69,7 +69,7 @@ struct async_msg
 #endif
 
     // construct from log_msg with given type
-    async_msg(async_logger_ptr &&worker, async_msg_type the_type, details::log_msg &&m)
+    async_msg(async_logger_ptr &&worker, async_msg_type the_type, const details::log_msg &m)
         : msg_type(the_type)
         , level(m.level)
         , time(m.time)
@@ -146,9 +146,9 @@ public:
         }
     }
 
-    void post_log(async_logger_ptr &&worker_ptr, details::log_msg &&msg, async_overflow_policy overflow_policy)
+    void post_log(async_logger_ptr &&worker_ptr, const details::log_msg &msg, async_overflow_policy overflow_policy)
     {
-        async_msg async_m(std::forward<async_logger_ptr>(worker_ptr), async_msg_type::log, std::forward<log_msg>(msg));
+        async_msg async_m(std::forward<async_logger_ptr>(worker_ptr), async_msg_type::log, msg);
         post_async_msg_(std::move(async_m), overflow_policy);
     }
 
diff --git a/include/spdlog/logger.h b/include/spdlog/logger.h
index aa524f70..e8a238fb 100644
--- a/include/spdlog/logger.h
+++ b/include/spdlog/logger.h
@@ -137,7 +137,7 @@ public:
     virtual std::shared_ptr<logger> clone(std::string logger_name);
 
 protected:
-    virtual void sink_it_(details::log_msg &msg);
+    virtual void sink_it_(const details::log_msg &msg);
     virtual void flush_();
 
     bool should_flush_(const details::log_msg &msg);