Ruled by Mars, the planet of passion and action, red is one of Aries' colors. A few years back, wearing red lipstick at work was seen as an overly-confident move.
With women rising in the work force, it is now seen as a go-getter move. In many industries, including government agencies, law, banking, and PR, it is totally fine to wear red lipstick, even at 10 am.
If you have an important meeting, wearing it will help you project confidence and will hint you are prepared for anything that gets thrown at you.
The one time to avoid wearing red lipstick is during a first interview. Wait until you get the job, then go for it!