diff --git a/irc/metadata.go b/irc/metadata.go
index 8485862d..254df951 100644
--- a/irc/metadata.go
+++ b/irc/metadata.go
@@ -105,11 +105,10 @@ func syncChannelMetadata(server *Server, rb *ResponseBuffer, channel *Channel) {
 	}
 }
 
-var metadataEvilCharsRegexp = regexp.MustCompile("[^A-Za-z0-9_./-]+")
+var validMetadataKeyRegexp = regexp.MustCompile("^[A-Za-z0-9_./-]+$")
 
 func metadataKeyIsEvil(key string) bool {
-	return len(key) == 0 || // key needs to contain stuff
-		metadataEvilCharsRegexp.MatchString(key) // key can't contain the stuff it can't contain
+	return !validMetadataKeyRegexp.MatchString(key)
 }
 
 func metadataCanIEditThisKey(client *Client, targetObj MetadataHaver, key string) bool {