They have attracted consumers in a grey market, bolstered by social media claims for a host of unproven uses, and with scant safety and efficacy evidence from human studies.
"Americans are going to be buying these anyway. Our objective was to make sure that there is a regulated marketplace, so that what they're getting is what they claim to be, that is safe, that the factories are inspected," Kennedy said in an interview on Fox News' The Will Cain Show.
Kennedy's comments were in response to a question about a proposed policy change that the US Food and Drug Administration submitted on Thursday to the White House for review. The proposal could make it easier for pharmacies to compound certain peptides.
Outside advisers to the FDA had recommended in July that the agency loosen restrictions on six of seven peptides under review, including the popular BPC-157, against the guidance of Food and Drug Administration staff.
Peptides, which are being used for everything from pain to muscle growth and injury recovery and as a beauty aid despite the lack of scientific evidence of their efficacy, have been promoted widely on social media, and by Kennedy himself.
Kennedy has previously said he was "a big fan of peptides" and had used them to help recover from injuries.
They are built from short chains of amino acids, the same building blocks the body uses to make proteins.
The ones under consideration have not been approved by the FDA as safe or effective.
Compounding pharmacies are allowed to mix ingredients of approved medicines in specialised doses and under other circumstances, such as drug shortages.
