diff --git a/fixtures/output/example-0001.d.ts b/fixtures/output/example-0001.d.ts
index d9c38e4..4deb818 100644
--- a/fixtures/output/example-0001.d.ts
+++ b/fixtures/output/example-0001.d.ts
@@ -111,7 +111,7 @@ declare interface Options<T> {
   defaultConfig: T
 }
 
-export declare async function loadConfig<T extends Record<string, unknown>>(options: Options<T>): Promise<T>;
+export declare function loadConfig<T extends Record<string, unknown>>(options: Options<T>): Promise<T>;
 
 
 declare const dtsConfig: DtsGenerationConfig;
diff --git a/src/extract.ts b/src/extract.ts
index f0194eb..e4f5fed 100644
--- a/src/extract.ts
+++ b/src/extract.ts
@@ -1410,7 +1410,7 @@ export function processFunctionDeclaration(
     name,
     params,
     returnType,
-    isAsync,
+    isAsync, // it should be unused
     generics,
   } = extractFunctionSignature(declaration)
 
@@ -1422,7 +1422,6 @@ export function processFunctionDeclaration(
   const parts = [
     isExported ? 'export' : '',
     'declare',
-    isAsync ? 'async' : '',
     'function',
     name,
     generics,