diff --git a/lib/insert.js b/lib/insert.js
index 67f76ed..c06881e 100644
--- a/lib/insert.js
+++ b/lib/insert.js
@@ -28,7 +28,7 @@ module.exports = function insert(str, options) {
   if (m) newlines = m[0];
 
   // does the file have front-matter?
-  if (/^---/.test(str)) {
+  if (/^---\n.*\n---\n/.test(str)) {
     // extract it temporarily so the syntax
     // doesn't get mistaken for a heading
     obj = utils.matter(str);
@@ -50,6 +50,9 @@ module.exports = function insert(str, options) {
     sections.splice(1, 0, open + toc(last, options).content + '\n\n' + close);
   }
 
+  // Trim empty sections to avoid adding newlines to document in join
+  sections = sections.filter((section) => section.length > 0);
+
   var resultString = sections.join('\n\n') + newlines;
   // if front-matter was found, put it back now
   if (obj) {
diff --git a/package.json b/package.json
index 25d988d..90a06c4 100644
--- a/package.json
+++ b/package.json
@@ -14,6 +14,7 @@
     "David Mohl (https://dvcrn.github.io)",
     "Federico Soave (https://github.com/Feder1co5oave)",
     "Gary Green (https://github.com/garygreen)",
+    "Gregory Danielson III (https://gregdan3.dev)",
     "Jon Schlinkert (http://twitter.com/jonschlinkert)",
     "Josh Duff (https://tehshrike.github.io)",
     "Matt Ellis (http://sticklebackplastic.com)",
diff --git a/test/expected/commented-header.md b/test/expected/commented-header.md
new file mode 100644
index 0000000..5754fb1
--- /dev/null
+++ b/test/expected/commented-header.md
@@ -0,0 +1,12 @@
+<!-- toc -->
+
+- [First Heading](#first-heading)
+- [Second Heading](#second-heading)
+
+<!-- tocstop -->
+
+# First Heading
+
+<!-- # Commented Heading -->
+
+# Second Heading
\ No newline at end of file
diff --git a/test/expected/inline-code.md b/test/expected/inline-code.md
new file mode 100644
index 0000000..3f6380f
--- /dev/null
+++ b/test/expected/inline-code.md
@@ -0,0 +1,9 @@
+<!-- toc -->
+
+- [The `log-in` element](#the-log-in-element)
+
+<!-- tocstop -->
+
+## The `log-in` element
+
+Lorem ipsum dolor sit amet, qui minim labore adipisicing minim sint cillum sint consectetur cupidatat.
\ No newline at end of file
diff --git a/test/expected/symbols-in-heading.md b/test/expected/symbols-in-heading.md
new file mode 100644
index 0000000..500a4c1
--- /dev/null
+++ b/test/expected/symbols-in-heading.md
@@ -0,0 +1,14 @@
+<!-- toc -->
+
+- [Example Heading (With Parenthetic Comment)](#example-heading-with-parenthetic-comment)
+- [path/to/file.txt](#pathtofiletxt)
+
+<!-- tocstop -->
+
+## Example Heading (With Parenthetic Comment)
+
+Lorem ipsum dolor sit amet, qui minim labore adipisicing minim sint cillum sint consectetur cupidatat.
+
+## path/to/file.txt
+
+Lorem ipsum dolor sit amet, qui minim labore adipisicing minim sint cillum sint consectetur cupidatat.
\ No newline at end of file
diff --git a/test/fixtures/commented-header.md b/test/fixtures/commented-header.md
new file mode 100644
index 0000000..6722418
--- /dev/null
+++ b/test/fixtures/commented-header.md
@@ -0,0 +1,7 @@
+<!-- toc -->
+
+# First Heading
+
+<!-- # Commented Heading -->
+
+# Second Heading
\ No newline at end of file
diff --git a/test/fixtures/inline-code.md b/test/fixtures/inline-code.md
new file mode 100644
index 0000000..e904922
--- /dev/null
+++ b/test/fixtures/inline-code.md
@@ -0,0 +1,5 @@
+<!-- toc -->
+
+## The `log-in` element
+
+Lorem ipsum dolor sit amet, qui minim labore adipisicing minim sint cillum sint consectetur cupidatat.
\ No newline at end of file
diff --git a/test/fixtures/symbols-in-heading.md b/test/fixtures/symbols-in-heading.md
new file mode 100644
index 0000000..82ac6d3
--- /dev/null
+++ b/test/fixtures/symbols-in-heading.md
@@ -0,0 +1,9 @@
+<!-- toc -->
+
+## Example Heading (With Parenthetic Comment)
+
+Lorem ipsum dolor sit amet, qui minim labore adipisicing minim sint cillum sint consectetur cupidatat.
+
+## path/to/file.txt
+
+Lorem ipsum dolor sit amet, qui minim labore adipisicing minim sint cillum sint consectetur cupidatat.
\ No newline at end of file
diff --git a/test/test.js b/test/test.js
index e93e41b..fe231e6 100644
--- a/test/test.js
+++ b/test/test.js
@@ -426,4 +426,22 @@ describe('toc.insert', function() {
     assert.equal(strip(toc.insert(str, { linkify: true })), read('test/expected/insert.md'));
     assert.equal(strip(toc.insert(str, { linkify: false })), read('test/expected/insert-no-links.md'));
   });
+
+  it('should not mangle a file with an initial horizontal rule', function() {
+    assert.equal(toc.insert('---\nExample\n'),  '---\nExample\n');
+  })
+
+  it('should not generate a link to a commented heading', function() {
+    assert.equal(toc.insert(read('test/fixtures/commented-header.md')), read('test/expected/commented-header.md'));
+  })
+
+
+  it('should not strip inline code', function() {
+    assert.equal(toc.insert(read('test/fixtures/inline-code.md')), read('test/expected/inline-code.md'))
+  })
+
+  it('should strip symbols instead of making them dashes in slug', function() {
+    assert.equal(toc.insert(read('test/fixtures/symbols-in-heading.md')), read('test/expected/symbols-in-heading.md'))
+  })
+
 });