Read MoreAckman's new Herbalife play: A documentary film
Herbalife has been aggressive in defending itself since Ackman unveiled his now-famous $1 billion bet against the company in December 2012. But it took a particularly strong approach with its latest salvo.
For example, Herbalife rejected Pershing Square's claim that there was no real demand for its products given the alleged focus on making money from recruiting other distributors, not actually using or selling the nutritional shake formulas and other goods.
Read MorePershing Square surges 25% in first half
"A pillar of Pershing Square's thesis is its assertion that there is no genuine consumer demand," the company said. "Thus, Pershing Square's thesis is built upon the proposition that last year, roughly a half million people collectively decided to simply discard $881 million worth of Herbalife products rather than get the refund to which they were entitled. And, according to Pershing Square, this has happened every year for the past 34 years."
Herbalife stock is down about 23 percent in 2014.
—By CNBC's Lawrence Delevingne