diff --git a/packages/react-devtools-shared/src/backend/profilingHooks.js b/packages/react-devtools-shared/src/backend/profilingHooks.js
index 9544b72511f6a..2280d6156e683 100644
--- a/packages/react-devtools-shared/src/backend/profilingHooks.js
+++ b/packages/react-devtools-shared/src/backend/profilingHooks.js
@@ -75,7 +75,7 @@ export function createProfilingHooks({
   reactVersion,
 }: {|
   getDisplayNameForFiber: (fiber: Fiber) => string | null,
-  getLaneLabelMap?: () => Map<Lane, string>,
+  getLaneLabelMap?: () => Map<Lane, string> | null,
   reactVersion: string,
 |}): DevToolsProfilingHooks {
   function markMetadata() {
@@ -108,8 +108,10 @@ export function createProfilingHooks({
 
     if (typeof getLaneLabelMap === 'function') {
       const map = getLaneLabelMap();
-      const labels = Array.from(map.values()).join(',');
-      markAndClear(`--react-lane-labels-${labels}`);
+      if (map != null) {
+        const labels = Array.from(map.values()).join(',');
+        markAndClear(`--react-lane-labels-${labels}`);
+      }
     }
   }
 
diff --git a/packages/react-devtools-shared/src/backend/types.js b/packages/react-devtools-shared/src/backend/types.js
index b751882396955..99a86464236f2 100644
--- a/packages/react-devtools-shared/src/backend/types.js
+++ b/packages/react-devtools-shared/src/backend/types.js
@@ -152,7 +152,7 @@ export type ReactRenderer = {
   scheduleRefresh?: Function,
   // 18.0+
   injectProfilingHooks?: (profilingHooks: DevToolsProfilingHooks) => void,
-  getLaneLabelMap?: () => Map<Lane, string>,
+  getLaneLabelMap?: () => Map<Lane, string> | null,
   ...
 };
 
diff --git a/packages/react-reconciler/src/ReactFiberDevToolsHook.new.js b/packages/react-reconciler/src/ReactFiberDevToolsHook.new.js
index 2978f7b3279b5..a05cc6933e53d 100644
--- a/packages/react-reconciler/src/ReactFiberDevToolsHook.new.js
+++ b/packages/react-reconciler/src/ReactFiberDevToolsHook.new.js
@@ -230,17 +230,21 @@ function injectProfilingHooks(profilingHooks: DevToolsProfilingHooks): void {
   injectedProfilingHooks = profilingHooks;
 }
 
-function getLaneLabelMap(): Map<Lane, string> {
-  const map: Map<Lane, string> = new Map();
+function getLaneLabelMap(): Map<Lane, string> | null {
+  if (enableSchedulingProfiler) {
+    const map: Map<Lane, string> = new Map();
 
-  let lane = 1;
-  for (let index = 0; index < TotalLanes; index++) {
-    const label = ((getLabelForLane(lane): any): string);
-    map.set(lane, label);
-    lane *= 2;
-  }
+    let lane = 1;
+    for (let index = 0; index < TotalLanes; index++) {
+      const label = ((getLabelForLane(lane): any): string);
+      map.set(lane, label);
+      lane *= 2;
+    }
 
-  return map;
+    return map;
+  } else {
+    return null;
+  }
 }
 
 export function markCommitStarted(lanes: Lanes): void {
diff --git a/packages/react-reconciler/src/ReactFiberDevToolsHook.old.js b/packages/react-reconciler/src/ReactFiberDevToolsHook.old.js
index d26d12236c24c..982c46ba44f36 100644
--- a/packages/react-reconciler/src/ReactFiberDevToolsHook.old.js
+++ b/packages/react-reconciler/src/ReactFiberDevToolsHook.old.js
@@ -230,17 +230,21 @@ function injectProfilingHooks(profilingHooks: DevToolsProfilingHooks): void {
   injectedProfilingHooks = profilingHooks;
 }
 
-function getLaneLabelMap(): Map<Lane, string> {
-  const map: Map<Lane, string> = new Map();
+function getLaneLabelMap(): Map<Lane, string> | null {
+  if (enableSchedulingProfiler) {
+    const map: Map<Lane, string> = new Map();
 
-  let lane = 1;
-  for (let index = 0; index < TotalLanes; index++) {
-    const label = ((getLabelForLane(lane): any): string);
-    map.set(lane, label);
-    lane *= 2;
-  }
+    let lane = 1;
+    for (let index = 0; index < TotalLanes; index++) {
+      const label = ((getLabelForLane(lane): any): string);
+      map.set(lane, label);
+      lane *= 2;
+    }
 
-  return map;
+    return map;
+  } else {
+    return null;
+  }
 }
 
 export function markCommitStarted(lanes: Lanes): void {
diff --git a/packages/shared/forks/ReactFeatureFlags.testing.js b/packages/shared/forks/ReactFeatureFlags.testing.js
index 163731c01dd29..1d2ff85dd3899 100644
--- a/packages/shared/forks/ReactFeatureFlags.testing.js
+++ b/packages/shared/forks/ReactFeatureFlags.testing.js
@@ -12,7 +12,7 @@ import typeof * as ExportsType from './ReactFeatureFlags.testing';
 
 export const debugRenderPhaseSideEffectsForStrictMode = false;
 export const enableDebugTracing = false;
-export const enableSchedulingProfiler = false;
+export const enableSchedulingProfiler = __PROFILE__;
 export const warnAboutDeprecatedLifecycles = true;
 export const replayFailedUnitOfWorkWithInvokeGuardedCallback = false;
 export const enableProfilerTimer = __PROFILE__;