While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a closer look at particularly stock-shaking upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of Nu Skin Enterprises (NYSE:NUS) rebounded 3% today after DA Davidson upgraded the anti-aging products company from "neutral" to "buy."

So what: Along with the upgrade, analyst Timothy Ramey boosted his price target on the stock to $110 (from $100), representing about 19% worth of upside to where it sits now. The stock fell hard in early trading Wednesday on apparently no news, but Ramey views it as a solid buy-in opportunity given Nu Skin's seemingly conservative guidance for the current quarter.

Now what: DA Davidson raised its Q3 EPS estimate from $1.40 to $1.49, well ahead of Nu Skin's outlook of $1.35-$1.40, as well as Wall Street's view of $1.41.

"Management gave themselves some breathing room in the final analysis, shifting $45 million of sales out of 3Q into 4Q on the chance that there would be a manufacturing or shipping snafu on the first part of the weight loss LTO in China," DA Davidson said. "We made a mental note at the time to revisit the 3Q estimate if it appears that the China LTO was as successful as planned. As best as we can tell, it was."

But while the stock might set up nicely for a short-term earnings pop, Nu Skin's 20-plus P/E and controversial multi-level marketing model might give long-term investors more gray hair than they can handle. 

Fool contributor Brian Pacampara has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.