I just turned 27, and I keep taking inventory of everything physically deteriorating on my person—my once silky hair has gotten coarser; I have this line on my forehead as if I’ve scowled too much like Myrna Loy in my Twitter avatar; I get tired at approximately 10:22pm; I’m more aware of veins; the theme song for Downton Abbey sends a jolt of excitement through me—and my skin has never been drier. And not from what my doctor and psychic call “the drinking!” (I am a religious water consumer.) A combination of this epically long, dry winter, my 100-year-old blasting radiator, and getting closer to my deathbed are to blame.

But I’m not one to sit around and pile on more serums—oh no, I need magic, and right now magic is so in. There are more wands vaguely reminiscent of vibrators on the market for your glowing visage available now than ever before. One just came out that sells itself as an ultrasound for your face, claiming that it will finally fully activate the goods in your cleanser—what is going to happen then? You find an entirely new face waiting beneath? Terrifying!

Anyway, I digress. So one particularly nasty and snowy afternoon last week, I clomped into Kiehl’s and begged for some help. I use a lot of Kiehl’s products—using their stuff just always seems to work, and simultaneously makes me feel richer than I am...I feeling I enjoy. I call it “being a pretend millionaire,” which is also how I feel when I buy pressed juices.

The lovely saleswoman who first complimented my booties suggested we test the moisture in my face. Great! I love readings: aura readings, psychic readings, book readings, meter readings—the best things in life are read, I always say (I’ve never said that). She whipped out a chunky pen they call a “Dehydration Analyzer Tool!” a black-and-white pen that literally says “Moisture Monitor” on it. She then wiped a section of my cheek and briefly probed me for a few seconds, which is great because I’ve always wanted to be probed! I found that same pen on a dubious shopping site called Ali Express for $19.60 (18 percent off)—it’s made in China, and the company’s website says it “[identifies] the humidity level of the skin by using the latest Bioelectric Impedance Analysis (BIA) technology…” Sure.

Moment of truth: I was a 31.

Here’s the breakdown: Ideal humidity level is 50 percent. (I suggested Kiehl’s give customers a prize if they get this—the salesperson thought I was joking.) A number under 30 means you have a dry problem, and it's time to lubricate your face. A range between 30 and 40 means you’re somewhat dehydrated, so always be striving toward that 50 (and equal pay in the workplace, if we’re going to be throwing out goals here).

I left the store with some new moisturizer to try, and I came back a week later to test my skin again, gentleman caller in tow. I was a 37!! And they also added on an oil test, which I passed with flying splotches. My gentleman, though, was a 42 and truly enjoyed his moment of triumph—which can only be explained by his using up of my own creams, serums, potions, and lotions.

But wait a second, what the hell is Bioelectric Impedance Analysis? According to Michelle Obama’s Shape Up website (= trusty!), it’s a way of analyzing body fat using electrodes that measure the how fast a current goes through the body—if it goes fast, lucky you! You have less fat to get in the way. There are tests where you get these little electrodes placed all over you to measure this, or you can buy a special scale.

Kim Robertson, Kiehl’s director of customer experience, told me that the pen “sends an undetectable current through the surface layers of the skin, bouncing back to the device, and measuring the resistance to that current,” and that “since water is an excellent conductor of electricity, the more hydrated the skin, the less resistance the current will have. So the faster the current comes back to the device, the more hydrated the skin is.” Boom. Science.

…or Magic? Now, I’ve purchased a lot of snake oil in the past...I consider it a hobby. The accuracy and legitimacy of the pen is a little dubious to me, especially since a few dermatologists I spoke to had never heard of it (and the fact that it looks like something you would buy in one of those beauty stores in Flushing that also sells 200 varieties of face masks). But overall, what I took from this is that your skin could probably be more moisturized. I used to think I had oily skin and therefore needed to avoid adding extra layers of junk to my face. Actually, my skin was creating oil to offset the dryness—so joke’s on me, as it always is...

—Alex Beggs

Alex Beggs is an Associate Editor at VanityFair.com. Follow her on Twitter if you’re into that kind of thing. And read her ITG report on lip stains ( t he best, worst, most memorable) right here.