How to permanently delete text messages from iPhone storage?

Iphone 5, even when I delete all messages from phone and sync with itunes nothing changes still taking up a large portion of storage. Any help? Thank you!

I'm just saying here, unless you had a massive & I mean massive amount of texts over years of use then that would make a serious dent in storage. I checked the database for my text messages over 5 years of owning an iPhone, updating, backups etc & it only accounted for 24MB. (November 2008 - June 2013).

Try an app for the computer called PhoneClean if you want to free up some space. Wouldn't deal with texts specifically but should help regain space in other areas. No it does not erase any data & also is free.

Thanks for not answering the question.