I've traveled too many times to count with preloaded syringes in my shaving kit. I then pack the shaving kit in my carryon bag.
In the past, I have put my shoes on top of the approximate location of the shaving kit (the shoes have steel shanks), but don't worry about it anymore.
I've never been stopped.

Of course, I look like a businessman; I'm always wearing a dress (or polo) shirt, many times with a jacket and good pair of pants. If you don't look like you fit a 'high risk' profile, don't worry. I've only had secondary searches a couple of the MANY times that I've gone through airport security, and have never had any problems.
OTOH, I was sitting in the Chicago airport (with juice in my carryon) and there was a passenger with a ton of gaudy jewelry, wearing a basketball jersey, definitely lookin' like he'd been hitting the juice rather heavy. To the point that he looked like a freak with the amount of muscles that he had. If I looked like him, there's no way that I'd be carrying juice through security.