diff --git a/render-wasm/_build_env b/render-wasm/_build_env
index eccf3a400..c5299dd46 100644
--- a/render-wasm/_build_env
+++ b/render-wasm/_build_env
@@ -28,6 +28,7 @@ _CARGO_PARAMS="--target=wasm32-unknown-emscripten";
 
 if [ "$_BUILD_MODE" = "release" ]; then
     _CARGO_PARAMS="--release $_CARGO_PARAMS"
+    EMCC_CFLAGS="-Os $EMCC_CFLAGS"
 else
     EMCC_CFLAGS="$EMCC_CFLAGS -sMALLOC=emmalloc-debug"
 fi