diff --git a/doc/zstd_manual.html b/doc/zstd_manual.html
index 5b9f07960..cdfeb7094 100644
--- a/doc/zstd_manual.html
+++ b/doc/zstd_manual.html
@@ -43,9 +43,8 @@
   The library supports regular compression levels from 1 up to ZSTD_maxCLevel(),
   which is currently 22. Levels >= 20, labeled `--ultra`, should be used with
   caution, as they require more memory. The library also offers negative
-  compression levels (all negative integers are valid levels), which extend the
-  range of speed vs. ratio preferences to increasingly extremely strongly
-  prioritize speed.
+  compression levels, which extend the range of speed vs. ratio preferences.
+  The lower the level, the faster the speed (at the cost of compression).
 
   Compression can be done in:
     - a single step (described as Simple API)
diff --git a/lib/zstd.h b/lib/zstd.h
index 72fc3590b..ac6f918a7 100644
--- a/lib/zstd.h
+++ b/lib/zstd.h
@@ -46,9 +46,8 @@ extern "C" {
   The library supports regular compression levels from 1 up to ZSTD_maxCLevel(),
   which is currently 22. Levels >= 20, labeled `--ultra`, should be used with
   caution, as they require more memory. The library also offers negative
-  compression levels (all negative integers are valid levels), which extend the
-  range of speed vs. ratio preferences to increasingly extremely strongly
-  prioritize speed.
+  compression levels, which extend the range of speed vs. ratio preferences.
+  The lower the level, the faster the speed (at the cost of compression).
 
   Compression can be done in:
     - a single step (described as Simple API)