diff --git a/lib/actions/message-actions.js b/lib/actions/message-actions.js
--- a/lib/actions/message-actions.js
+++ b/lib/actions/message-actions.js
@@ -42,6 +42,7 @@
 export type FetchMessagesBeforeCursorInput = {
   +threadID: string,
   +beforeMessageID: string,
+  +numMessagesToFetch?: ?number,
 };
 const fetchMessagesBeforeCursor =
   (
@@ -61,6 +62,10 @@
       },
     };
 
+    if (input.numMessagesToFetch) {
+      requests[keyserverID].numberPerThread = input.numMessagesToFetch;
+    }
+
     const responses = await callKeyserverEndpoint('fetch_messages', requests);
     return {
       threadID,
@@ -77,6 +82,7 @@
 
 export type FetchMostRecentMessagesInput = {
   +threadID: string,
+  +numMessagesToFetch?: ?number,
 };
 
 const fetchMostRecentMessagesActionTypes = Object.freeze({
@@ -102,6 +108,10 @@
       },
     };
 
+    if (input.numMessagesToFetch) {
+      requests[keyserverID].numberPerThread = input.numMessagesToFetch;
+    }
+
     const responses = await callKeyserverEndpoint('fetch_messages', requests);
     return {
       threadID,
diff --git a/lib/shared/message-utils.js b/lib/shared/message-utils.js
--- a/lib/shared/message-utils.js
+++ b/lib/shared/message-utils.js
@@ -713,7 +713,12 @@
   };
 }
 
-function useFetchMessages(threadInfo: ThreadInfo): () => Promise<void> {
+type FetchMessagesOptions = {
+  +numMessagesToFetch?: ?number,
+};
+function useFetchMessages(
+  threadInfo: ThreadInfo,
+): (options?: ?FetchMessagesOptions) => Promise<void> {
   const oldestMessageServerID = useOldestMessageServerID(threadInfo.id);
   const callFetchMessagesBeforeCursor = useFetchMessagesBeforeCursor();
   const callFetchMostRecentMessages = useFetchMostRecentMessages();
@@ -729,45 +734,50 @@
     state => state.messageStore.threads[threadID]?.messageIDs,
   );
 
-  return React.useCallback(async () => {
-    if (threadTypeIsThick(threadInfo.type)) {
-      const promise = (async () => {
-        const currentNumberOfFetchedMessages = messageIDs?.length ?? 0;
-        return await fetchThickThreadMessages(
-          threadID,
-          defaultNumberPerThread,
-          currentNumberOfFetchedMessages,
+  return React.useCallback(
+    async (options?: ?FetchMessagesOptions) => {
+      const numMessagesToFetch = options?.numMessagesToFetch;
+      if (threadTypeIsThick(threadInfo.type)) {
+        const promise = (async () => {
+          const currentNumberOfFetchedMessages = messageIDs?.length ?? 0;
+          return await fetchThickThreadMessages(
+            threadID,
+            numMessagesToFetch ?? defaultNumberPerThread,
+            currentNumberOfFetchedMessages,
+          );
+        })();
+        await dispatchActionPromise(
+          fetchMessagesBeforeCursorActionTypes,
+          promise,
         );
-      })();
-      await dispatchActionPromise(
-        fetchMessagesBeforeCursorActionTypes,
-        promise,
-      );
-      return;
-    }
-    if (oldestMessageServerID) {
-      await dispatchActionPromise(
-        fetchMessagesBeforeCursorActionTypes,
-        callFetchMessagesBeforeCursor({
-          threadID,
-          beforeMessageID: oldestMessageServerID,
-        }),
-      );
-    } else {
-      await dispatchActionPromise(
-        fetchMostRecentMessagesActionTypes,
-        callFetchMostRecentMessages({ threadID }),
-      );
-    }
-  }, [
-    callFetchMessagesBeforeCursor,
-    callFetchMostRecentMessages,
-    dispatchActionPromise,
-    messageIDs?.length,
-    oldestMessageServerID,
-    threadID,
-    threadInfo.type,
-  ]);
+        return;
+      }
+      if (oldestMessageServerID) {
+        await dispatchActionPromise(
+          fetchMessagesBeforeCursorActionTypes,
+          callFetchMessagesBeforeCursor({
+            threadID,
+            beforeMessageID: oldestMessageServerID,
+            numMessagesToFetch,
+          }),
+        );
+      } else {
+        await dispatchActionPromise(
+          fetchMostRecentMessagesActionTypes,
+          callFetchMostRecentMessages({ threadID, numMessagesToFetch }),
+        );
+      }
+    },
+    [
+      callFetchMessagesBeforeCursor,
+      callFetchMostRecentMessages,
+      dispatchActionPromise,
+      messageIDs?.length,
+      oldestMessageServerID,
+      threadID,
+      threadInfo.type,
+    ],
+  );
 }
 
 export {