diff --git a/changelog.d/5-internal/polysemy-oom b/changelog.d/5-internal/polysemy-oom
new file mode 100644
index 00000000000..82b4530ebc9
--- /dev/null
+++ b/changelog.d/5-internal/polysemy-oom
@@ -0,0 +1 @@
+Reduce Polysemy-induced high memory requirements
diff --git a/nix/haskell-pins.nix b/nix/haskell-pins.nix
index ce404aa2326..0082da92620 100644
--- a/nix/haskell-pins.nix
+++ b/nix/haskell-pins.nix
@@ -203,6 +203,41 @@ let
         tasty-hunit = "hunit";
       };
     };
+    polysemy = {
+      src = fetchgit {
+        url = "https://github.com/polysemy-research/polysemy.git";
+        rev = "3855786e58bf397ca8204f3a79d19c24485dabd4";
+        sha256 = "sha256-4ans30VWuSMC9HNFb6FWQyc30oxJd2dmFrMGu5/dLg0=";
+      };
+    };
+    polysemy-plugin = {
+      src = fetchgit {
+        url = "https://github.com/polysemy-research/polysemy.git";
+        rev = "3855786e58bf397ca8204f3a79d19c24485dabd4";
+        sha256 = "sha256-4ans30VWuSMC9HNFb6FWQyc30oxJd2dmFrMGu5/dLg0=";
+      };
+      packages = {
+        polysemy-plugin = "polysemy-plugin";
+      };
+    };
+    polysemy-check = {
+      src = fetchgit {
+        url = "https://github.com/polysemy-research/polysemy-check.git";
+        rev = "4c0d3ff929ae22ae68d962f7f3f7056f357bf7ac";
+        sha256 = "sha256-8XeCeJWbkdqrUf6tERFMoGM8xRI5l/nKNqI810kzMs0=";
+      };
+    };
+    kind-generics = {
+      src = fetchgit {
+        url = "https://gitlab.com/trupill/kind-generics.git";
+        rev = "f4ad2bcfacc9c3dcecf64c069d086926465cab2c";
+        sha256 = "sha256-uvQMV8aTNyTN+ozrseohexbCneVPMO35Jf1eEhLPk78=";
+      };
+      packages = {
+        kind-generics = "kind-generics";
+        kind-generics-th = "kind-generics-th";
+      };
+    };
     # This can be removed once postie 0.6.0.3 (or later) is in nixpkgs
     postie = {
       src = fetchgit {
@@ -213,10 +248,6 @@ let
     };
   };
   hackagePins = {
-    kind-generics = {
-      version = "0.4.1.0";
-      sha256 = "sha256-gD9b9AXpLkpPSAeg8oPBU7tsHtSNQjxIZKBo+7+r3+c=";
-    };
     wai-route = {
       version = "0.4.0";
       sha256 = "sha256-DSMckKIeVE/buSMg8Mq+mUm1bYPYB7veA11Ns7vTBbc=";
diff --git a/services/brig/src/Brig/Effects/SFT.hs b/services/brig/src/Brig/Effects/SFT.hs
index 7672876e4fa..de325e810e2 100644
--- a/services/brig/src/Brig/Effects/SFT.hs
+++ b/services/brig/src/Brig/Effects/SFT.hs
@@ -37,7 +37,6 @@ import Imports hiding (fromException, intercalate)
 import Network.HTTP.Client
 import Polysemy
 import Polysemy.Error hiding (try)
-import Polysemy.Internal
 import Polysemy.TinyLog
 import qualified System.Logger as Log
 import URI.ByteString (uriPath)
diff --git a/services/federator/src/Federator/Monitor/Internal.hs b/services/federator/src/Federator/Monitor/Internal.hs
index 4fd0faef579..4d38328bdc0 100644
--- a/services/federator/src/Federator/Monitor/Internal.hs
+++ b/services/federator/src/Federator/Monitor/Internal.hs
@@ -35,6 +35,7 @@ import qualified Network.TLS as TLS
 import Polysemy (Embed, Member, Members, Sem, embed)
 import qualified Polysemy
 import qualified Polysemy.Error as Polysemy
+import Polysemy.Final (Final)
 import qualified Polysemy.Resource as Polysemy
 import Polysemy.TinyLog (TinyLog)
 import qualified Polysemy.TinyLog as Log
@@ -103,8 +104,8 @@ watchPathEvents (WatchedDir _ _) = [MoveIn, Create]
 -- directory watches as they get deleted and recreated.
 type Watches = Map RawFilePath (WatchDescriptor, WatchedPath)
 
-runSemDefault :: Logger -> Sem '[TinyLog, Embed IO] a -> IO a
-runSemDefault logger = Polysemy.runM . Log.loggerToTinyLog logger
+runSemDefault :: Logger -> Sem '[TinyLog, Embed IO, Final IO] a -> IO a
+runSemDefault logger = Polysemy.runFinal . Polysemy.embedToFinal . Log.loggerToTinyLog logger
 
 logErrors ::
   Members '[TinyLog, Polysemy.Error FederationSetupError] r =>
@@ -123,10 +124,10 @@ logAndIgnoreErrors ::
 logAndIgnoreErrors = void . Polysemy.runError . logErrors
 
 delMonitor ::
-  (Members '[TinyLog, Embed IO] r) =>
+  (Members '[TinyLog, Embed IO, Final IO] r) =>
   Monitor ->
   Sem r ()
-delMonitor monitor = Polysemy.resourceToIO
+delMonitor monitor = Polysemy.resourceToIOFinal
   $ Polysemy.bracket
     (takeMVar (monLock monitor))
     (putMVar (monLock monitor))
diff --git a/services/federator/test/unit/Test/Federator/Monitor.hs b/services/federator/test/unit/Test/Federator/Monitor.hs
index dcb28815387..e448f62f2ef 100644
--- a/services/federator/test/unit/Test/Federator/Monitor.hs
+++ b/services/federator/test/unit/Test/Federator/Monitor.hs
@@ -125,7 +125,7 @@ withSilentMonitor reloads settings = do
       (runSem . delMonitor)
   pure tlsVar
   where
-    runSem = Polysemy.runM . Log.discardTinyLogs
+    runSem = Polysemy.runFinal . Polysemy.embedToFinal @IO . Log.discardTinyLogs
     runSemE action = do
       r <- runSem (Polysemy.runError @FederationSetupError action)
       writeChan reloads (either Just (const Nothing) r)
diff --git a/services/galley/src/Galley/API/Message.hs b/services/galley/src/Galley/API/Message.hs
index ffe54121b35..94d6809ce57 100644
--- a/services/galley/src/Galley/API/Message.hs
+++ b/services/galley/src/Galley/API/Message.hs
@@ -65,7 +65,7 @@ import Galley.Options
 import qualified Galley.Types.Clients as Clients
 import Galley.Types.Conversations.Members
 import Imports hiding (forkIO)
-import Polysemy
+import Polysemy hiding (send)
 import Polysemy.Error
 import Polysemy.Input
 import qualified Polysemy.TinyLog as P