diff --git a/library/alignment.h b/library/alignment.h
index aa4c430b96..aa09ff8569 100644
--- a/library/alignment.h
+++ b/library/alignment.h
@@ -31,13 +31,17 @@
 
 /*
  * Define MBEDTLS_EFFICIENT_UNALIGNED_ACCESS for architectures where unaligned memory
- * accesses are known to be safe and efficient.
+ * accesses are known to be efficient.
+ *
+ * All functions defined here will behave correctly regardless, but might be less
+ * efficient when this is not defined.
  */
 #if defined(__ARM_FEATURE_UNALIGNED) \
     || defined(__i386__) || defined(__amd64__) || defined(__x86_64__)
 /*
  * __ARM_FEATURE_UNALIGNED is defined where appropriate by armcc, gcc 7, clang 9
- * (and later versions); all x86 platforms should have efficient unaligned access.
+ * (and later versions) for Arm v7 and later; all x86 platforms should have
+ * efficient unaligned access.
  */
 #define MBEDTLS_EFFICIENT_UNALIGNED_ACCESS
 #endif