diff --git a/utils/wasm-builder/src/optimize.rs b/utils/wasm-builder/src/optimize.rs
index 88c3aed181f..0ad73346ecf 100644
--- a/utils/wasm-builder/src/optimize.rs
+++ b/utils/wasm-builder/src/optimize.rs
@@ -277,6 +277,7 @@ pub fn do_optimization(
         "z" => OptimizationOptions::new_optimize_for_size_aggressively(),
         _ => panic!("Invalid optimization level {}", optimization_level),
     }
+    .shrink_level(wasm_opt::ShrinkLevel::Level2)
     .add_pass(Pass::Dae)
     .add_pass(Pass::Vacuum)
     // the memory in our module is imported, `wasm-opt` needs to be told that
diff --git a/utils/wasm-builder/src/wasm_project.rs b/utils/wasm-builder/src/wasm_project.rs
index 2b7d3a04d49..579ad88445d 100644
--- a/utils/wasm-builder/src/wasm_project.rs
+++ b/utils/wasm-builder/src/wasm_project.rs
@@ -31,6 +31,8 @@ use std::{
 };
 use toml::value::Table;
 
+const OPT_LEVEL: &str = "z";
+
 /// Enum defining type of binary compiling: production program or metawasm.
 pub enum ProjectType {
     Program(Option<MetadataRepr>),
@@ -158,11 +160,11 @@ impl WasmProject {
         lib.insert("crate-type".into(), vec!["cdylib".to_string()].into());
 
         let mut dev_profile = Table::new();
-        dev_profile.insert("opt-level".into(), "s".into());
+        dev_profile.insert("opt-level".into(), OPT_LEVEL.into());
 
         let mut release_profile = Table::new();
         release_profile.insert("lto".into(), "fat".into());
-        release_profile.insert("opt-level".into(), "z".into());
+        release_profile.insert("opt-level".into(), OPT_LEVEL.into());
         release_profile.insert("codegen-units".into(), 1.into());
 
         let mut production_profile = Table::new();
@@ -317,7 +319,7 @@ extern "C" fn metahash() {{
             let path = optimize::optimize_wasm(
                 original_copy_wasm_path.clone(),
                 opt_wasm_path.clone(),
-                "z",
+                "4",
                 true,
             )
             .map(|res| {