Whether the new interpretation is correct will not be known until it is challenged in court.
"We are satisfied they are covered by the act, but the test of that is always a court case," Medsafe group manager Stuart Jessamine said.
Medsafe still plans to reclassify some peptides, with performance-enhancing SARMS to be added to the schedule - a move that Australia is also instituting in May. Another substance, the popular tanning agent and aphrodisiac Melanotan II (MTII), would remain unclassified as more work needed to be done before it could be added to the schedule, Dr Jessamine said.
For now MTII exists in a loophole that means it is illegal to marketit, sell it or conduct a clinical trialwith it without a permit, but notillegal to import it.
Dr Jessamine said fewer than 10 prosecutions had been brought in New Zealand over the importation of performance-enhancing drugs, and all of those were for amounts deemed to indicate trafficking or selling.
"Our tendency has always been that if you are a kind of enthusiastic amateur we won't take action against you."
Peptide death link 'tenuous'
The death of a 23-year-old NRL player in Australia has been linked to peptides - but a leading cancer specialist says the connection is "tenuous at best".
Cronulla league player Jon Mannah died from Hodgkin's lymphoma earlier this year, aged 23. He had recovered from a first bout of the lymphoma in 2009 to play the first five NRL matches of 2011.
News Ltd newspapers on Friday questioned whether Mannah's cancer relapse could be linked to peptide use.
But leading cancer expert Professor Robert Baxter described the link as "tenuous at best".
Cronulla were caught up in the probe into the use of prohibited substances by the Australian Sports Anti-Doping Authority in February.
- AAP