diff --git a/lib/http.c b/lib/http.c
index f5ccda8f67..90e6df19c0 100644
--- a/lib/http.c
+++ b/lib/http.c
@@ -1572,11 +1572,14 @@ CURLcode Curl_http_connect(struct Curl_easy *data, bool *done)
     /* nothing else to do except wait right now - we're not done here. */
     return CURLE_OK;
 
-  if(data->set.haproxyprotocol) {
+  if(data->set.haproxyprotocol && !data->state.is_haproxy_hdr_sent) {
     /* add HAProxy PROXY protocol header */
     result = add_haproxy_protocol_header(data);
     if(result)
       return result;
+
+    /* do not send the header again after successful try */
+    data->state.is_haproxy_hdr_sent = TRUE;
   }
 #endif
 
diff --git a/lib/urldata.h b/lib/urldata.h
index 1ae7aa4a5e..7f1acc4c5a 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -1461,6 +1461,10 @@ struct UrlState {
   trailers_state trailers_state; /* whether we are sending trailers
                                     and what stage are we at */
 #endif
+#ifndef CURL_DISABLE_PROXY
+  /* to keep track whether we already sent PROXY header or not */
+  BIT(is_haproxy_hdr_sent);
+#endif
 #ifdef USE_HYPER
   bool hconnect;  /* set if a CONNECT request */
   CURLcode hresult; /* used to pass return codes back from hyper callbacks */