A Wall Street Journal investigation detailed Facebook’s intimate knowledge of flaws that riddle its system – flaws that can cause harm. The Journal reviewed documents and research reports, along with online employee discussions.

A key piece of that report found that the company also knew of the harmful effects its products – most notably Instagram – could be on the health of teenaged girls.

A source familiar with the matter confirmed to FOX Business that the whistleblower behind the leaked documents in the report has agreed to work with Congress and appear before the Senate Commerce Committee Consumer protection panel before the end of the year.

Facebook also confirmed to FOX Business that the company will send its global head of safety, Antigone Davis, to testify.

Facebook has faced increasing pressure from lawmakers over its various practices, but the most recent revelations have brought incredible scrutiny and criticism from politicians.

Congress would at least partially shield the whistleblower from fallout over any disclosures, an aide to Sen. Marsh Blackburn, R-Tenn., told The Washington Post.

"We hear from teachers and parents and pediatricians and child psychologists and counselors of the addictive nature of the social media apps," Blackburn told the Post on Wednesday.

According to the Journal’s investigation, "the company found that Instagram is harmful for a sizable percentage of them, most notably teenage girls, more so than other social-media platforms."

"In public, Facebook has consistently played down the app’s negative effects, including in comments to Congress, and hasn’t made its research public or available to academics or lawmakers who have asked for it," the report adds.

Facebook leadership has already testified before Congress multiple times – most recently to testify earlier this year on the spread of misinformation across social media platforms (including Google and Twitter).