diff --git a/core/common/src/Clock.kt b/core/common/src/Clock.kt
index e9cd9137e..2fcc3d67d 100644
--- a/core/common/src/Clock.kt
+++ b/core/common/src/Clock.kt
@@ -78,7 +78,11 @@ public fun Clock.todayIn(timeZone: TimeZone): LocalDate =
  * Please only use this conversion function on the [Clock] instances that are fully controlled programmatically.
  */
 @ExperimentalTime
+@Deprecated("This function is deprecated because Clock.System.asTimeSource " +
+        "can be confused with TimeSource.Monotonic, which are very different. " +
+        "See https://github.com/Kotlin/kotlinx-datetime/issues/372", level = DeprecationLevel.WARNING)
 public fun Clock.asTimeSource(): TimeSource.WithComparableMarks = object : TimeSource.WithComparableMarks {
+    @ExperimentalTime
     override fun markNow(): ComparableTimeMark = InstantTimeMark(now(), this@asTimeSource)
 }
 
diff --git a/core/common/test/ClockTimeSourceTest.kt b/core/common/test/ClockTimeSourceTest.kt
index 561cd2221..17882ae6b 100644
--- a/core/common/test/ClockTimeSourceTest.kt
+++ b/core/common/test/ClockTimeSourceTest.kt
@@ -12,6 +12,7 @@ import kotlin.time.Duration.Companion.days
 import kotlin.time.Duration.Companion.nanoseconds
 
 @OptIn(ExperimentalTime::class)
+@Suppress("DEPRECATION")
 class ClockTimeSourceTest {
     @Test
     fun arithmetic() {