diff --git a/src/basic/string-util.c b/src/basic/string-util.c
index 5621ffc768..b2919164d6 100644
--- a/src/basic/string-util.c
+++ b/src/basic/string-util.c
@@ -77,38 +77,6 @@ char* strnappend(const char *s, const char *suffix, size_t b) {
         return r;
 }
 
-char* strjoin_real(const char *x, ...) {
-        va_list ap;
-        size_t l = 1;
-        char *r, *p;
-
-        va_start(ap, x);
-        for (const char *t = x; t; t = va_arg(ap, const char *)) {
-                size_t n;
-
-                n = strlen(t);
-                if (n > SIZE_MAX - l) {
-                        va_end(ap);
-                        return NULL;
-                }
-                l += n;
-        }
-        va_end(ap);
-
-        p = r = new(char, l);
-        if (!r)
-                return NULL;
-
-        va_start(ap, x);
-        for (const char *t = x; t; t = va_arg(ap, const char *))
-                p = stpcpy(p, t);
-        va_end(ap);
-
-        *p = 0;
-
-        return r;
-}
-
 char* strstrip(char *s) {
         if (!s)
                 return NULL;
@@ -843,12 +811,14 @@ char* strip_tab_ansi(char **ibuf, size_t *_isz, size_t highlight[2]) {
 }
 
 char* strextend_with_separator_internal(char **x, const char *separator, ...) {
+        _cleanup_free_ char *buffer = NULL;
         size_t f, l, l_separator;
         bool need_separator;
         char *nr, *p;
         va_list ap;
 
-        assert(x);
+        if (!x)
+                x = &buffer;
 
         l = f = strlen_ptr(*x);
 
@@ -856,13 +826,14 @@ char* strextend_with_separator_internal(char **x, const char *separator, ...) {
         l_separator = strlen_ptr(separator);
 
         va_start(ap, separator);
-        for (;;) {
-                const char *t;
+        for (const char *t;;) {
                 size_t n;
 
                 t = va_arg(ap, const char *);
                 if (!t)
                         break;
+                if (t == POINTER_MAX)
+                        continue;
 
                 n = strlen(t);
 
@@ -895,6 +866,8 @@ char* strextend_with_separator_internal(char **x, const char *separator, ...) {
                 t = va_arg(ap, const char *);
                 if (!t)
                         break;
+                if (t == POINTER_MAX)
+                        continue;
 
                 if (need_separator && separator)
                         p = stpcpy(p, separator);
@@ -906,9 +879,13 @@ char* strextend_with_separator_internal(char **x, const char *separator, ...) {
         va_end(ap);
 
         assert(p == nr + l);
-
         *p = 0;
 
+        /* If no buffer to extend was passed in return the start of the buffer */
+        if (buffer)
+                return TAKE_PTR(buffer);
+
+        /* Otherwise we extended the buffer: return the end */
         return p;
 }
 
diff --git a/src/basic/string-util.h b/src/basic/string-util.h
index a1592b6e6d..1bcb1c40e3 100644
--- a/src/basic/string-util.h
+++ b/src/basic/string-util.h
@@ -108,8 +108,7 @@ char* first_word(const char *s, const char *word) _pure_;
 
 char* strnappend(const char *s, const char *suffix, size_t length);
 
-char* strjoin_real(const char *x, ...) _sentinel_;
-#define strjoin(a, ...) strjoin_real((a), __VA_ARGS__, NULL)
+#define strjoin(a, ...) strextend_with_separator_internal(NULL, NULL, a, __VA_ARGS__, NULL)
 
 #define strjoina(a, ...)                                                \
         ({                                                              \
diff --git a/src/test/test-string-util.c b/src/test/test-string-util.c
index b692af6cc0..2b44905346 100644
--- a/src/test/test-string-util.c
+++ b/src/test/test-string-util.c
@@ -262,6 +262,12 @@ TEST(strextend) {
         ASSERT_STREQ(str, "0123");
         assert_se(strextend(&str, "456", "78", "9"));
         ASSERT_STREQ(str, "0123456789");
+
+        assert_se(strextend(&str, "more", NULL, "huch"));
+        ASSERT_STREQ(str, "0123456789more");
+
+        assert_se(strextend(&str, "MORE", POINTER_MAX, "HUCH"));
+        ASSERT_STREQ(str, "0123456789moreMOREHUCH");
 }
 
 TEST(strextend_with_separator) {
@@ -285,6 +291,9 @@ TEST(strextend_with_separator) {
         ASSERT_STREQ(str, "start,,1,234");
         assert_se(strextend_with_separator(&str, ";", "more", "5", "678"));
         ASSERT_STREQ(str, "start,,1,234;more;5;678");
+
+        assert_se(strextend_with_separator(&str, ";", "xxxx", POINTER_MAX, "yyy"));
+        ASSERT_STREQ(str, "start,,1,234;more;5;678;xxxx;yyy");
 }
 
 TEST(strrep) {
@@ -400,6 +409,10 @@ TEST(strjoin) {
         actual = strjoin("foo", NULL, "bar");
         ASSERT_STREQ(actual, "foo");
         free(actual);
+
+        actual = strjoin("foo", POINTER_MAX, "bar");
+        ASSERT_STREQ(actual, "foobar");
+        free(actual);
 }
 
 TEST(strcmp_ptr) {