diff --git a/src/argparse.cpp b/src/argparse.cpp
index 6b0d16e..e2b966d 100644
--- a/src/argparse.cpp
+++ b/src/argparse.cpp
@@ -9,10 +9,13 @@ void print_help(const char *argv0)
     "\n\t-s: set first displayed byte to START"
     "\n\t-l: display LEN bytes (only in terminal mode)"
     "\n\t-w: display WIDTH bytes per column"
-    "\n\t-e: display some extended info (may slow down the startup)"
+    "\n\t-e: display some extended info(*) (may slow down the startup)"
     "\n\t-n: list the names of the RNTuples found in the file and exit"
     "\n"
-    "\nNOTE: if `ntuple_name' is not passed, rntviewer will look for the first RNTuple in the TFile."
+    "\nNOTES:"
+    "\n- if `ntuple_name' is not passed, rntviewer will look for the first RNTuple in the TFile."
+    "\n- (*) \"some extended info\" currently means the total uncompressed size of the pages and"
+    "\n      their compression ratio."
     "\n"
   , argv0);
 }