Drug Free Sport New Zealand and the World Anti-Doping Agency have warned athletes be "extremely careful" of deer velvet supplements.
Chief executive Graeme Steel has released a statement saying in light of global controversy surrounding the products risks and risks to positive doping, no safety guarantees can be made and athletes risk prosecution if they test positive.
Drug Free Sport NZ confirmed the products "can contain insulin-like Growth Factor (IGF-1), which is prohibited in sport both in and out-of-competition."
"Athletes who return a positive test will be prosecuted by DFSNZ and are unlikely to be able to fall back on any lack of fault provision given the warnings which have been issued," the statement continued.
On Saturday, New Zealand Golf, in an attempt to protect the integrity of deer velvet ambassador of 20 years Sir Bob Charles, pre-empting anti-doping experts saying Charles, 76, was being subject to "unfounded" and "unfair" suggestion of drug violations.
The position of NZ Golf was based on a technicality, that taking the product in pill form, as opposed to sprays or "SWATS" (Sports With Alternatives to Steroids), is safe.
But the experts are much less convinced, with WADA also weighing in on the issue.
"There is no absolute guarantee in the scientific literature that IGF-1 taken orally will not influence the plasma level of IGF-1, which may then influence the result of anti-doping tests," a WADA statement said.
Steel says DFSNZ accepts IGF-1 is a naturally occurring at very low levels in meat and dairy products, but that is not to be confused with laboratory production of supplements.
"It is accepted that IGF-1 occurs naturally at very low "trace" levels in deer velvet as it does in some foodstuffs including milk products," the DFSNZ statement said.
"Athletes generally need not be concerned that trace levels of prohibited substances, which may be found in normal foodstuffs, will result in positive tests.
DFSNZ also re-iterated the risks when any person subject to compliance to the world anti-doping code takes when opting for supplements.
"When athletes take supplements, there is potential for prohibited substances to occur at higher than natural trace levels due to manufacturing processes," they said.
"DFSNZ has no ability to assess the true level of any component contained within a supplement or how that substance may be metabolised. Consequently it must alert athletes to the presence of prohibited substances irrespective of levels.
"DFSNZ will continue to monitor this matter but, having considered the information currently available, has determined that intervention related to possible historical use of oral forms of deer velvet is not warranted at this time.
This statement is made by DFSNZ to athletes who are subject to the Sports Anti-Doping Rules. DFSNZ makes no comment about the appropriateness of these products for use by the general public who are not bound by the sports anti-doping rules."
- Fairfax Media