diff --git a/cmake/README.md b/cmake/README.md
index 01b6f6a60e..6255307ef3 100644
--- a/cmake/README.md
+++ b/cmake/README.md
@@ -1798,6 +1798,32 @@ Requires installation of the Voro++ library
 </tbody>
 </table>
 
+### USER-COLVARS Package
+
+Requires a C++11 compiler to compile with the Lepton library included.
+
+<table>
+<thead>
+<tr>
+  <th>Option</th>
+  <th>Description</th>
+  <th>Values</th>
+</tr>
+</thead>
+<tbody>
+<tr>
+  <td><code>COLVARS_LEPTON</code></td>
+  <td>Enable the use of the Lepton library inside the Colvars library.
+  <td>
+  <dl>
+    <dt><code>on</code> (default)</dt>
+    <dt><code>off</code></dt>
+  </dl>
+  </td>
+</tr>
+</tbody>
+</table>
+
 ### USER-LATTE Package
 
 Requires installation of the LATTE library
diff --git a/doc/src/Build_extras.txt b/doc/src/Build_extras.txt
index 0a25a344ca..ef62beccd0 100644
--- a/doc/src/Build_extras.txt
+++ b/doc/src/Build_extras.txt
@@ -644,7 +644,10 @@ USER-COLVARS package :h4,link(user-colvars)
 
 [CMake build]:
 
-No additional settings are needed besides "-D PKG_USER-COLVARS=yes".
+The USER-COLVARS package requires the use of a C++11 compiler to compile
+the included Lepton library. You can set the flag "-D COLVARS_LEPTON=no"
+in addition to "-D PKG_USER-COLVARS=yes" in order to instruct CMake to
+skip building and including the Lepton library into the USER-COLVARS code.
 
 [Traditional make]: