Jessica Alba's Honest Company is confronting what is arguably the business's first major foray into customer complaints that go viral.

The company has been getting a lot of heat from customers who say that the company's "natural mineral-based" sunscreen fails to do precisely what it's designed to do: prevent sunburn.

Angry customers have been posting pictures of their sunburnt shoulders, backs, and scalps on Twitter and Facebook.

The company issued a statement Friday to the Today show, defending the product:

"Our Sunscreen Lotion was tested, by an independent 3rd party, against the protocols prescribed by the U.S. Food & Drug Administration's (FDA) monograph for over-the-counter sunscreen products. The results showed that our product is effective and safe for use as an 80 minute water-resistant (FDA's highest rating), SPF 30 sunscreen lotion in accordance with FDA regulations when used as directed." 

A request for comment from the company today received no response; Inc. will update this story should the company provide any additional information. 

If you look at the company's webpage for the sunscreen now, the product is listed as sold out and no negative reviews are visible. On Twitter, though, the company is reaching out to customers and directing them to email for help. 

The sunscreen kerfuffle comes right as the business has been growing at an extremely fast clip. When Inc. featured Alba on its November cover, the three-year-old company had a $1 billion valuation and more than a $150 million in revenue. In recent months, Honest--best known for its baby, home, and personal-care products--has expanded its product line-up to include infant formula and non-toxic feminine care, and beauty products are soon to follow. The company has product kiosks in several major airports and also plans to launch in China by the end of the year.

When Alba and CEO Brian Lee attended Inc. magazine's GrowCo conference in April, I asked the two if they worried about Honest's fast pace of growth and how they would know if the company started to grow too fast.

"The way that you know if you're growing too fast is really about the customer and the community," Lee told me. "They'll let you know. Cracks start forming and leaks get bigger. The first thing you see is a decrease in customer satisfaction."

Alba, who is Chief Creative Officer, oversees the training of the company's customer service representatives. "We do listen to our customers and we're pretty malleable," she said on stage. 

This isn't the first product Honest customers have complained about, though it appears to have gained the most traction. Customers complained about Honest's baby wipes early on. Four months later, the company re-launched wipes that were bigger and thicker, though it had to move production to a China to do it. 

In its statement to the Today show, Honest said that the negative reviews on the sunscreen are outliers.

"The number of complaints received on our own website about our Sunscreen Lotion constitute less than one half of one percent of all units actually sold at We stand behind the safety and efficacy of this product."

NBC Chicago reported last month that the company had reformulated its sunscreen and cut the level zinc oxide from 20 percent to 9.3 percent, noting that the majority of other zinc oxide sunscreens on the market typically contain between 18 and 25 percent of the mineral. The FDA requires that manufacturers test their own products. 

Honest Company responded to NBC's report and explained that it reformulated the product to reduce the whitening effect on skin and to make it easier to apply.