Maria Sharapova has received a boost with support from one of her sponsors and business partners.

The Russian has seen major sponsors Nike, Tag Heuer and Porsche all distance themselves from her since she made the shocking announcement on Monday that she had failed a drug test.

Sharapova, the world's highest-earning female athlete for the last 11 years, faces losing a large chunk of her income but skincare company Supergoop is standing by her.

Sharapova signed a deal to be the face of the brand, which focuses on sun safety, in 2014 as well as becoming co-owner with founder Holly Thaggard.

Thaggard said in a statement: "While we are surprised and disheartened by Maria Sharapova's recent announcement, we value our relationship with her as a co-owner of Supergoop! and ambassador for our common cause of conquering the epidemic of skin cancer.

"We appreciate Maria's candour and will continue to support her as the ITF investigation unfolds."

The International Tennis Federation, meanwhile, confirmed that Sharapova missed five opportunities in December alone to learn that meldonium, the drug she tested positive for, had become a banned substance.

Documents detailing the prohibited substances for 2016 were distributed to players on December 3 and posted on the ITF website four days later.

On December 11 the WTA notified players that the documents were available while the ITF provided players with a link to them on December 22 - Sharapova admitted in her press conference she had received it but not clicked on it.

Then on December 29, the WTA sent another reminder of the availability of the documents to players.

Sharapova said at her press conference that she had been prescribed meldonium for 10 years by her family doctor because of health issues such as an irregular heartbeat and a history of diabetes in her family.

It was put on the banned list by the World Anti-Doping Agency in 2016 due to "evidence of its use by athletes with the intention of enhancing performance".