diff --git a/dbms/src/Core/Settings.h b/dbms/src/Core/Settings.h
index 27e06ffec10..833282bba3c 100644
--- a/dbms/src/Core/Settings.h
+++ b/dbms/src/Core/Settings.h
@@ -221,8 +221,8 @@ struct Settings : public SettingsCollection<Settings>
     M(SettingBool, empty_result_for_aggregation_by_empty_set, false, "Return empty result when aggregating without keys on empty set.") \
     M(SettingBool, allow_distributed_ddl, true, "If it is set to true, then a user is allowed to executed distributed DDL queries.") \
     M(SettingUInt64, odbc_max_field_size, 1024, "Max size of filed can be read from ODBC dictionary. Long strings are truncated.") \
-    M(SettingUInt64, query_profiler_real_time_period_ns, 0, "Period for real clock timer of query profiler (in nanoseconds). Set 0 value to turn off real clock query profiler") \
-    M(SettingUInt64, query_profiler_cpu_time_period_ns, 0, "Period for CPU clock timer of query profiler (in nanoseconds). Set 0 value to turn off CPU clock query profiler") \
+    M(SettingUInt64, query_profiler_real_time_period_ns, 0, "Highly experimental. Period for real clock timer of query profiler (in nanoseconds). Set 0 value to turn off real clock query profiler. Recommended value is at least 10000000 (100 times a second) for single queries or 1000000000 (once a second) for cluster-wide profiling.") \
+    M(SettingUInt64, query_profiler_cpu_time_period_ns, 0, "Highly experimental. Period for CPU clock timer of query profiler (in nanoseconds). Set 0 value to turn off CPU clock query profiler. Recommended value is at least 10000000 (100 times a second) for single queries or 1000000000 (once a second) for cluster-wide profiling.") \
     \
     \
     /** Limits during query execution are part of the settings. \