Adding the shortcode for membership level

When I try to add the shortcode " [level-premium-member] then a closing shortcode "[/level-premium-member]", the content within that shortcode are not showing when I access the page as a non-member but when I access as a member the content within that appears but the shortcode is also visible. It shows like this "[level-premium-member]this is for members only[/level-premium-member] ?
Why does this happen?