diff --git a/doc/APIreference/functions.rst b/doc/APIreference/functions.rst
index e13ad19d..a86386d5 100644
--- a/doc/APIreference/functions.rst
+++ b/doc/APIreference/functions.rst
@@ -459,7 +459,7 @@ Multiply vector by (inertia matrix)^(1/2).
 .. mujoco-include:: mj_addM
 
 Add inertia matrix to destination matrix.
-Destination can be sparse uncompressed, or dense when all int* are NULL
+Destination can be sparse or dense when all int* are NULL.
 
 .. _mj_applyFT:
 
diff --git a/include/mujoco/mujoco.h b/include/mujoco/mujoco.h
index 5bca71ea..b955cb13 100644
--- a/include/mujoco/mujoco.h
+++ b/include/mujoco/mujoco.h
@@ -485,7 +485,7 @@ MJAPI void mj_mulM(const mjModel* m, const mjData* d, mjtNum* res, const mjtNum*
 MJAPI void mj_mulM2(const mjModel* m, const mjData* d, mjtNum* res, const mjtNum* vec);
 
 // Add inertia matrix to destination matrix.
-// Destination can be sparse uncompressed, or dense when all int* are NULL
+// Destination can be sparse or dense when all int* are NULL.
 MJAPI void mj_addM(const mjModel* m, mjData* d, mjtNum* dst, int* rownnz, int* rowadr, int* colind);
 
 // Apply Cartesian force and torque (outside xfrc_applied mechanism).
diff --git a/python/mujoco/introspect/functions.py b/python/mujoco/introspect/functions.py
index b74e222f..f62a0e7a 100644
--- a/python/mujoco/introspect/functions.py
+++ b/python/mujoco/introspect/functions.py
@@ -2900,7 +2900,7 @@ FUNCTIONS: Mapping[str, FunctionDecl] = dict([
                  ),
              ),
          ),
-         doc='Add inertia matrix to destination matrix. Destination can be sparse uncompressed, or dense when all int* are NULL',  # pylint: disable=line-too-long
+         doc='Add inertia matrix to destination matrix. Destination can be sparse or dense when all int* are NULL.',  # pylint: disable=line-too-long
      )),
     ('mj_applyFT',
      FunctionDecl(
diff --git a/src/engine/engine_support.c b/src/engine/engine_support.c
index 541cf31f..3d95da43 100644
--- a/src/engine/engine_support.c
+++ b/src/engine/engine_support.c
@@ -1062,7 +1062,7 @@ void mj_mulM2(const mjModel* m, const mjData* d, mjtNum* res, const mjtNum* vec)
 
 
 // add inertia matrix to destination matrix
-//  destination can be sparse uncompressed, or dense when all int* are NULL
+//  destination can be sparse or dense when all int* are NULL
 void mj_addM(const mjModel* m, mjData* d, mjtNum* dst,
              int* rownnz, int* rowadr, int* colind) {
   // sparse
diff --git a/src/engine/engine_support.h b/src/engine/engine_support.h
index 220979da..818e9622 100644
--- a/src/engine/engine_support.h
+++ b/src/engine/engine_support.h
@@ -131,7 +131,7 @@ MJAPI void mj_mulM(const mjModel* m, const mjData* d, mjtNum* res, const mjtNum*
 MJAPI void mj_mulM2(const mjModel* m, const mjData* d, mjtNum* res, const mjtNum* vec);
 
 // add inertia matrix to destination matrix
-//  destination can be sparse uncompressed, or dense when all int* are NULL
+//  destination can be sparse or dense when all int* are NULL
 MJAPI void mj_addM(const mjModel* m, mjData* d, mjtNum* dst,
                    int* rownnz, int* rowadr, int* colind);