Ryan Lochte, the second most decorated male Olympic swimmer of all time, has been banned 14 months for receiving an intravenous infusion without a therapeutic use exemption, a violation which he unwittingly self-reported on social media, the US Anti-Doping Agency (USADA) .

USADA was made aware,  of the potential infraction when the 33-year-old American star posted a since-deleted photo of himself receiving the injection on Instagram with the hashtag #ivdrip, adding that Lochte “fully cooperated” with the ensuing investigation.

US officials further clarified that Lochte, who has brought home 12 medals from the past four Olympics including six golds, was not using a banned substance, but that doping rules prohibit athletes from receiving IV infusions or injections unless “legitimately received in the course of hospital treatment, surgical procedures, or clinical diagnostic investigations”.

“This is devastating for my family and me,” Lochte said at a news conference in Florida later Monday.

He added: “I know it sounds like a harsh penalty for something unintentional and where I didn’t put anything prohibited in my body, but a rule is a rule and I accept that there is a technical violation. I am hopeful other athletes will learn from my mistake and be mindful of this rule, as well as others.”

Lochte said he took the IV containing B12 and other vitamins available over the counter because his wife and son had been sick and he sought a preventative boost for his immune system.

Usada said the ban is retroactive to 24 May, which was the day he posted the photo, and will run through June 2019, ruling him out of the next two major international meets: August’s Pan Pacific Championships and the 2019 World Championships in Gwangju, South Korea.

Lochte will also be withdrawn from the four events he’d entered at the US national championships, which begin Wednesday in Irvine, California.