diff --git a/src/main/java/strman/Strman.java b/src/main/java/strman/Strman.java
index 7d68723..cdac971 100644
--- a/src/main/java/strman/Strman.java
+++ b/src/main/java/strman/Strman.java
@@ -28,7 +28,6 @@
 package strman;
 
 import java.util.*;
-import java.util.function.BiFunction;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 import java.util.regex.Matcher;
@@ -498,7 +497,7 @@ public abstract class Strman {
      * @param first  The first String
      * @param second The second String
      * @return true if first and second are not equal false otherwise
-     * @deprecated  use unequal instead
+     * @deprecated use unequal instead
      */
     public static boolean inequal(final String first, final String second) {
         return !Objects.equals(first, second);
@@ -721,11 +720,10 @@ public abstract class Strman {
     public static String removeLeft(final String value, final String prefix, final boolean caseSensitive) {
         validate(value, NULL_STRING_PREDICATE, NULL_STRING_MSG_SUPPLIER);
         validate(prefix, NULL_STRING_PREDICATE, NULL_STRING_MSG_SUPPLIER);
-        BiFunction<String, String, String> fx = (f, s) -> f.startsWith(s) ? f.replaceFirst(s, "") : f;
         if (caseSensitive) {
-            return fx.apply(value, prefix);
+            return value.startsWith(prefix) ? value.substring(prefix.length()) : value;
         }
-        return fx.apply(value.toLowerCase(), prefix.toLowerCase());
+        return value.toLowerCase().startsWith(prefix.toLowerCase()) ? value.substring(prefix.length()) : value;
     }
 
     /**
@@ -802,7 +800,7 @@ public abstract class Strman {
         if (caseSensitive) {
             return value.replace(search, newValue);
         }
-        return value.toLowerCase().replace(search.toLowerCase(), newValue);
+        return Pattern.compile(search, Pattern.CASE_INSENSITIVE).matcher(value).replaceAll(Matcher.quoteReplacement(newValue));
     }
 
     /**
@@ -1061,7 +1059,7 @@ public abstract class Strman {
     public static String toDecamelize(final String value, final String chr) {
         String camelCasedString = toCamelCase(value);
         String[] words = camelCasedString.split("(?=\\p{Upper})");
-        return Arrays.stream(words).map(w -> w.toLowerCase()).collect(joining(Optional.ofNullable(chr).orElse(" ")));
+        return Arrays.stream(words).map(String::toLowerCase).collect(joining(Optional.ofNullable(chr).orElse(" ")));
     }
 
     /**
diff --git a/src/test/java/strman/StrmanTest.java b/src/test/java/strman/StrmanTest.java
index f510324..be931e4 100644
--- a/src/test/java/strman/StrmanTest.java
+++ b/src/test/java/strman/StrmanTest.java
@@ -25,6 +25,7 @@
  */
 
 package strman;
+
 import org.junit.Test;
 
 import java.util.Arrays;
@@ -827,4 +828,21 @@ public class StrmanTest {
     }
 
 
+    @Test
+    public void removeLeft_shouldNotLowercaseWhenCaseInsensitive() throws Exception {
+        String result = removeLeft("This HAS A THIS IN FRONT", "THIS ", false);
+        assertThat(result, is("HAS A THIS IN FRONT"));
+    }
+
+    @Test
+    public void replace_shouldNotLowercaseWhenCaseInsensitive() throws Exception {
+        String result = replace("One and two and THREE and Four", "and", "&", false);
+        assertThat(result, is("One & two & THREE & Four"));
+    }
+
+    @Test
+    public void removeRight_shouldNotLowercaseWhenCaseInsensitive() throws Exception {
+        String result = removeRight("Remove the END at the end", " END", false);
+        assertThat(result, is("Remove the END at the"));
+    }
 }
\ No newline at end of file