What happened

Shares of Herbalife Ltd. (HLF -1.72%) were moving higher last month after the nutritional supplement provider posted a strong first-quarter earnings report. According to data from S&P Global Market Intelligence, the stock finished up 13.5% for the month of May.

As the chart below shows, the gains came following the company's earnings release at the beginning of the month.

HLF Chart

HLF data by YCharts

So what

Shares of Herbalife gained 12% on May 5 as the multi-level marketer delivered quarterly results ahead of its own guidance. Volume sales grew 1% in the quarter though overall revenue fell 2% to $1.1 billion due to currency exchange. That still beat estimates of $1.04 billion.

On the bottom line, adjusted earnings per share fell from $1.35 a year ago to $1.24, but that also beat expectations at just $0.87. The report was closely watched as it was the company's first quarter since the Federal Trade Commission mandated changes in its business model after Herbalife paid a $200 million fine last year to settle allegations of being a pyramid scheme.

The Herbalife logo

Image source: Herbalife.

CEO Michael Johnson said the quarter marked a "solid start to 2017" and touted the strength of the company's direct-selling model.

Now what

Herbalife also raised its guidance in the quarter as it's now calling for adjusted EPS of $4.05 to $4.45, up from a previous range of $3.65 to $4.05. Much of that was due to an adjustment in currency headwinds, however.

In June, Herbalife ran into some problems as the company issued a sales warning, saying that the second quarter would be challenging as its distributors adjusted to new requirements. However, the company increased its full-year adjusted EPS guidance to $4.10-$4.50. The stock fell 7% on the news, but has since recovered some of those losses.

While Herballife, which is a popular short, will remain a controversial stock, its business looks solid for now. I'd expect the stock to lose some of the volatility that investors are used to.