diff --git a/bazel/cc_toolchains/clang_cc_toolchain_config.bzl b/bazel/cc_toolchains/clang_cc_toolchain_config.bzl
index 748050650c9c..8b63fdeded43 100644
--- a/bazel/cc_toolchains/clang_cc_toolchain_config.bzl
+++ b/bazel/cc_toolchains/clang_cc_toolchain_config.bzl
@@ -661,20 +661,12 @@ def _impl(ctx):
 
     fuzzer = feature(
         name = "fuzzer",
-        flag_sets = [
-            flag_set(
-                actions = all_compile_actions + all_link_actions,
-                flag_groups = [flag_group(flags = [
-                    "-fsanitize=fuzzer-no-link",
-                ])],
-            ),
-            flag_set(
-                actions = all_compile_actions,
-                flag_groups = [flag_group(flags = [
-                    "-DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION",
-                ])],
-            ),
-        ],
+        flag_sets = [flag_set(
+            actions = all_compile_actions + all_link_actions,
+            flag_groups = [flag_group(flags = [
+                "-fsanitize=fuzzer-no-link",
+            ])],
+        )],
     )
 
     # Clang HARDENED_MODE has 4 possible values:
diff --git a/common/check.h b/common/check.h
index 10cd35cea54a..33386bcf5aa3 100644
--- a/common/check.h
+++ b/common/check.h
@@ -24,11 +24,8 @@ namespace Carbon {
   CARBON_INTERNAL_CHECK_CONDITION(condition) \
   ? (void)0 : CARBON_INTERNAL_CHECK(condition __VA_OPT__(, ) __VA_ARGS__)
 
-// DCHECK calls CHECK in debug or fuzzing mode, and does nothing otherwise.
-//
-// Note FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION is a standard define coming
-// from LibFuzzer: https://llvm.org/docs/LibFuzzer.html
-#if !defined(NDEBUG) || defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION)
+// DCHECK calls CHECK in debug mode, and does nothing otherwise.
+#ifndef NDEBUG
 #define CARBON_DCHECK(condition, ...) \
   CARBON_CHECK(condition __VA_OPT__(, ) __VA_ARGS__)
 #else
diff --git a/common/raw_hashtable_metadata_group.h b/common/raw_hashtable_metadata_group.h
index 572554dc28b2..943a49fa1fe4 100644
--- a/common/raw_hashtable_metadata_group.h
+++ b/common/raw_hashtable_metadata_group.h
@@ -480,12 +480,11 @@ class MetadataGroup : public Printable<MetadataGroup> {
   friend class BenchmarkSimdMetadataGroup;
 
   // All SIMD variants that we have an implementation for should be enabled for
-  // debugging and fuzzing. This lets us maintain a SIMD implementation even if
-  // it is not used due to performance reasons, and easily re-enable it if the
-  // performance changes.
+  // debugging. This lets us maintain a SIMD implementation even if it is not
+  // used due to performance reasons, and easily re-enable it if the performance
+  // changes.
   static constexpr bool DebugSimd =
-#if (!defined(NDEBUG) || defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION)) && \
-    (CARBON_NEON_SIMD_SUPPORT || CARBON_X86_SIMD_SUPPORT)
+#if !defined(NDEBUG) && (CARBON_NEON_SIMD_SUPPORT || CARBON_X86_SIMD_SUPPORT)
       true;
 #else
       false;