diff --git a/actix-http/src/client/h2proto.rs b/actix-http/src/client/h2proto.rs
index 0deb5c014..7292972de 100644
--- a/actix-http/src/client/h2proto.rs
+++ b/actix-http/src/client/h2proto.rs
@@ -1,4 +1,3 @@
-use std::convert::TryFrom;
 use std::future::Future;
 use std::time;
 
@@ -61,10 +60,14 @@ where
         BodySize::Empty => req
             .headers_mut()
             .insert(CONTENT_LENGTH, HeaderValue::from_static("0")),
-        BodySize::Sized(len) => req.headers_mut().insert(
-            CONTENT_LENGTH,
-            HeaderValue::try_from(format!("{}", len)).unwrap(),
-        ),
+        BodySize::Sized(len) => {
+            let mut buf = itoa::Buffer::new();
+
+            req.headers_mut().insert(
+                CONTENT_LENGTH,
+                HeaderValue::from_str(buf.format(len)).unwrap(),
+            )
+        }
     };
 
     // Extracting extra headers from RequestHeadType. HeaderMap::new() does not allocate.
@@ -87,7 +90,10 @@ where
     // copy headers
     for (key, value) in headers {
         match *key {
-            CONNECTION | TRANSFER_ENCODING => continue, // http2 specific
+            // TODO: consider skipping other headers according to:
+            //       https://tools.ietf.org/html/rfc7540#section-8.1.2.2
+            // omit HTTP/1.x only headers
+            CONNECTION | TRANSFER_ENCODING => continue,
             CONTENT_LENGTH if skip_len => continue,
             // DATE => has_date = true,
             _ => {}
diff --git a/actix-http/src/h1/encoder.rs b/actix-http/src/h1/encoder.rs
index 97916e7db..60062d559 100644
--- a/actix-http/src/h1/encoder.rs
+++ b/actix-http/src/h1/encoder.rs
@@ -633,9 +633,9 @@ mod tests {
         let mut res: Response<()> =
             Response::new(StatusCode::SWITCHING_PROTOCOLS).into_body::<()>();
         res.headers_mut()
-            .insert(DATE, HeaderValue::from_static(&""));
+            .insert(DATE, HeaderValue::from_static(""));
         res.headers_mut()
-            .insert(CONTENT_LENGTH, HeaderValue::from_static(&"0"));
+            .insert(CONTENT_LENGTH, HeaderValue::from_static("0"));
 
         let _ = res.encode_headers(
             &mut bytes,
diff --git a/actix-http/src/h2/dispatcher.rs b/actix-http/src/h2/dispatcher.rs
index 5ccd2a9d1..003a7034e 100644
--- a/actix-http/src/h2/dispatcher.rs
+++ b/actix-http/src/h2/dispatcher.rs
@@ -125,7 +125,7 @@ where
                     let pl = Payload::<crate::payload::PayloadStream>::H2(pl);
                     let mut req = Request::with_payload(pl);
 
-                    let head = &mut req.head_mut();
+                    let head = req.head_mut();
                     head.uri = parts.uri;
                     head.method = parts.method;
                     head.version = parts.version;
@@ -203,16 +203,22 @@ where
             BodySize::Empty => res
                 .headers_mut()
                 .insert(CONTENT_LENGTH, HeaderValue::from_static("0")),
-            BodySize::Sized(len) => res.headers_mut().insert(
-                CONTENT_LENGTH,
-                HeaderValue::try_from(format!("{}", len)).unwrap(),
-            ),
+            BodySize::Sized(len) => {
+                let mut buf = itoa::Buffer::new();
+
+                res.headers_mut().insert(
+                    CONTENT_LENGTH,
+                    HeaderValue::from_str(buf.format(len)).unwrap(),
+                )
+            }
         };
 
         // copy headers
         for (key, value) in head.headers.iter() {
             match *key {
-                // omit HTTP/1 only headers
+                // TODO: consider skipping other headers according to:
+                //       https://tools.ietf.org/html/rfc7540#section-8.1.2.2
+                // omit HTTP/1.x only headers
                 CONNECTION | TRANSFER_ENCODING => continue,
                 CONTENT_LENGTH if skip_len => continue,
                 DATE => has_date = true,
diff --git a/actix-http/src/response.rs b/actix-http/src/response.rs
index f96f8f9b6..c5a4aec13 100644
--- a/actix-http/src/response.rs
+++ b/actix-http/src/response.rs
@@ -498,7 +498,8 @@ impl ResponseBuilder {
     /// Disable chunked transfer encoding for HTTP/1.1 streaming responses.
     #[inline]
     pub fn no_chunking(&mut self, len: u64) -> &mut Self {
-        self.insert_header((header::CONTENT_LENGTH, len));
+        let mut buf = itoa::Buffer::new();
+        self.insert_header((header::CONTENT_LENGTH, buf.format(len)));
 
         if let Some(parts) = parts(&mut self.head, &self.err) {
             parts.no_chunking(true);
diff --git a/awc/src/request.rs b/awc/src/request.rs
index 812c0e805..c39e0b4cd 100644
--- a/awc/src/request.rs
+++ b/awc/src/request.rs
@@ -248,29 +248,28 @@ impl ClientRequest {
     /// Set content length
     #[inline]
     pub fn content_length(self, len: u64) -> Self {
-        self.append_header((header::CONTENT_LENGTH, len))
+        let mut buf = itoa::Buffer::new();
+        self.insert_header((header::CONTENT_LENGTH, buf.format(len)))
     }
 
     /// Set HTTP basic authorization header
-    pub fn basic_auth<U>(self, username: U, password: Option<&str>) -> Self
-    where
-        U: fmt::Display,
-    {
+    pub fn basic_auth(
+        self,
+        username: impl fmt::Display,
+        password: Option<impl fmt::Display>,
+    ) -> Self {
         let auth = match password {
             Some(password) => format!("{}:{}", username, password),
             None => format!("{}:", username),
         };
-        self.append_header((
+        self.insert_header((
             header::AUTHORIZATION,
             format!("Basic {}", base64::encode(&auth)),
         ))
     }
 
     /// Set HTTP bearer authentication header
-    pub fn bearer_auth<T>(self, token: T) -> Self
-    where
-        T: fmt::Display,
-    {
+    pub fn insert_auth(self, token: impl fmt::Display) -> Self {
         self.append_header((header::AUTHORIZATION, format!("Bearer {}", token)))
     }