"As a vegan brand, we are really not cool with animals getting sprayed in the face," said Song, who owns Snow Fox Skincare. "It sucks, because China is a huge market … it's a lot of money.

But she stopped cold after learning that the Chinese government mandated animal testing for imported cosmetics and skincare products.

When entrepreneur Phoebe Song launched her organic, vegan skincare line, she had big plans to sell around the world, including in China , the world's largest consumer market.

China requires skincare and cosmetics firms to submit to compulsory animal testing in government labs before regulators approve products for sale in the country. For brands like Song's Snow Fox, these regulations mean either allowing animal testing, or losing access to a market worth $29 billion last year, according to Euromonitor.

Experts say all firms selling to Chinese consumers now undergo animal testing for their products, including major foreign brands L'Oreal, Estee Lauder, Shiseido, and Proctor & Gamble.

None of those firms, among the top foreign cosmetics and skincare companies selling in China, responded to a request for comment.

Those companies state online that they do not engage in animal testing, but insert language that indicates exceptions are made where required. For instance, Estee Lauder says it "does not test on animals and we never ask others to do so on our behalf," according to a statement on its website. "If a regulatory body demands it for its safety or regulatory assessment, an exception can be made."

A 2013 estimate by the People for the Ethical Treatment of Animals found that China's mandatory regulations resulted in companies testing products on as many as 300,000 animals, according to the organization's senior vice president, Kathy Guillermo, who explained that an animal is killed after a test.

While there are alternative ways of testing the safety of beauty products, for instance, by using 3-D tissue models, experts said China currently lacks the know-how.

"They're just completely behind the curve in learning about the new science," said Erin Hill, president of U.S.-based Institute of In Vitro Sciences, which is training Chinese government scientists in new methods. IIVS also partners with companies, including foreign brands in China, to work on non-animal testing procedures.

Some change is happening: Late last year, the government moved to accept safety data collected through a non-animal test method, the 3T3 phototoxicity assay, which measures the safety of a chemical after exposure to light. The government hasn't said if this test is yet in use.

And in some provinces, companies domestically manufacturing ordinary products, like lotion and soap, can now apply to waive the animal testing requirements.

L'Oreal is one of the firms taking advantage of this, and some of its products, such as shampoo and body wash, are no longer animal tested in China, according to its website.

But China's murky regulatory environment is difficult to navigate and experts said getting such approvals can be spotty.

"It's a big task to make this shift — it comes down to having the right laboratories, the people skilled in these different methods, and also access to the equipment and the supplies you need," Hill said.

Pressure is increasing for China to adapt, as animal testing gets banned in more jurisdictions, including Europe, Australia, India and Israel. In the U.S., it has long been abandoned from standard practice.

Plus, if domestic Chinese firms want to sell abroad — especially in countries where such testing is no longer allowed — they'll need to substantiate the safety of their products via non-animal methods.

National regulator China Food and Drug Administration didn't respond to a request for comment.

For Hong Kong-based Song, she's simply decided not to sell her vegan products in China at the moment, despite the market potential. But sticking it out means sometimes, consumers don't cut her much slack.

"They say, 'you're supposed to be a big global brand — what global brand doesn't have sales channels in China?" Song said. "And we have to explain it's because we really don't want to torture some bunnies."