The app has already become the top shopping app on the iOS App Store in a handful of Western countries, including France, Spain and the UK, according to data from App Annie. And it’s taken the top spot in some Middle Eastern countries, too, including Saudi Arabia. In the US, it ranks behind only Amazon.

Shein’s success comes partly from effectively leveraging influencers in social media marketing campaigns, Forrester analyst Xiaofeng Wang said. By running targeted ads with influencers endorsing its products, Shein’s main Instagram account has pulled in more than 11 million followers. The company also runs separate accounts for different countries.

Back home in China, though, Shein doesn’t have such a big presence online. On the microblogging platform Weibo, Shein only operates one account -- and it’s for supplier recruitment. It has more than a dozen WeChat accounts, but nearly all of them also exist to serve suppliers and logistics partners.

The company isn’t relying simply on social media influencers. In some cases, it’s also pulling in bigger stars.

Shein’s aggressive marketing efforts aren’t limited to online, either. Shein launched a pop-up store in Paris last year, where it invited fashion journalists and bloggers to attend. The move generated a lot of buzz online, Wang said.

One advantage for the company is that it doesn’t operate any physical stores. It’s a strategy taken by other Chinese tech upstarts like Xiaomi, helping them grow early on before later expanding into physical retail.

With only the occasional pop-up store, Shein is able to keep costs down and more aggressively compete against rivals with large retail chains like H&M, according to Philip Wiggenraad, an independent retail analyst and former head of research at Tofugear.

Complaints aside, the platform’s impressive growth suggests many people think Shein is worth the gamble.

“Shein’s popularity in the West is centered around Gen Z consumers, who are willing to put up with the long fulfillment times of typically two to three weeks in order to benefit from the brand’s low prices,” Wiggenraad said.

Targeting that demographic could eventually pose a challenge for Shein, though.

“We are seeing that Gen Z consumers in the West are becoming more interested in companies that are into sustainability. Shein has absolutely not been transparent about its sourcing practices,” Wiggenraad said. “Given its extremely low prices, it is probably unable to sell a positive message in this area.”

Part of the challenge for the industry isn’t just conditions at the brand companies themselves, but the conditions across the supply chain. Judging from its posts on Chinese social media, Shein relies on thousands of small suppliers to manufacture its products. The company didn’t respond to questions about its manufacturing process or working conditions.

The company’s Chinese origin is also proving to be another challenge. Wiggenraad said rising anti-China sentiment, amplified by US-China tensions and the Covid-19 pandemic, is likely to strain the company’s further expansion in the global market.

An outright ban might be an extreme case, but it could affect how Shein manages its growth going forward.

“While this action is unlikely to be taken in Western markets, Shein will need to carefully consider how it positions its brand in these sensitive times,” Wiggenraad said.