Deep Thought. The reason why some newbies get phero responses right away is because of their already developed ability to generate phero responses. If your body isnt ready for competition, you wont generate the matching signatures.
To some extent, you wear pheros to affect others. To some extent, you wear pheros to affect your own body, which then generates totally different pheros (or reduces generation of other pheros) and thats what actually has the desired effect. See the next post.