diff --git a/changelog.d/5557.misc b/changelog.d/5557.misc
new file mode 100644
index 000000000000..0c90f498719f
--- /dev/null
+++ b/changelog.d/5557.misc
@@ -0,0 +1 @@
+Logging when running GC collection on generation 0 is now at the DEBUG level, not INFO.
diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py
index 1f30179b5169..eaf0aaa86e89 100644
--- a/synapse/metrics/__init__.py
+++ b/synapse/metrics/__init__.py
@@ -437,7 +437,10 @@ def f(*args, **kwargs):
         counts = gc.get_count()
         for i in (2, 1, 0):
             if threshold[i] < counts[i]:
-                logger.info("Collecting gc %d", i)
+                if i == 0:
+                    logger.debug("Collecting gc %d", i)
+                else:
+                    logger.info("Collecting gc %d", i)
 
                 start = time.time()
                 unreachable = gc.collect(i)