The bad guys are always one step ahead. That was the reality with party pills and it is much the same with illicit fitness supplements.
Testing supplement powders for potentially harmful and illegal substances is like searching for a needle in a haystack - only the person doing the searching has never actually seen a needle before, so has no idea what it looks like. And finding the needle is one thing, proving it really is a needle can be quite another. It's a time-consuming, painstaking process.
"There is a great deal of work involved," said Stewart Edwards, a senior forensic scientist at ESR.
"And what always happens is that as soon as we have gone to all that trouble we stop seeing that drug and the next one comes along."
Using an instrument called a gas chromatograph-mass spectrometer, samples of pre-workout supplements obtained by the Herald were screened for illicit substances by Mr Edwards.
The process involved separating the various chemical components in a sample and then matching them against recognised reference standards.
If a peak on the scientist's instrument matched a reference standard, bingo, there it was.
But what if a sample contained a new substance - one the lab had never come across before? That was the case with Frenzy and DMBA, the latest psychoactive stimulant now appearing in exercise supplements.
After multiple tests, the most Mr Edwards could say was that his analysis indicated the product contained DMBA. That was enough for the Psychoactive Regulatory Authority to have the product pulled from the shelves.
An international study of DMBA co-authored by Harvard Medical School associate professor Dr Pieter Cohen suggests Mr Edwards is right in predicting it won't be long until DMBA - which itself replaced banned stimulant DMAA - is in turn replaced. New Zealand law is almost powerless to stop the re-formulated - but possibly equally dangerous - products coming into the country.
Health supplements are regulated by a law that is 30 years old, the 1985 Dietary Supplements Regulations.
The law places no burden on producers and sellers to prove their products are safe or even effective before they go the market. Rules prohibit marketing claims over a product's ability to "alter the shape, structure, size or weight of the human body" but the penalties are such - typically $500 - that they are routinely ignored.
In the US, where many illicit supplements are concocted, the situation is as dire.
"In general, there is no law that requires any supplement to work and no law that requires any supplement to be safe," Dr Cohen said.
The body responsible for overseeing the multibillion-dollar industry, the Federal Drug Administration, had effectively been neutered by powerful lobbyists.
"There are senators here in our Congress who are very much aligned with the industry."
In New Zealand food supplements are the responsibility of the Ministry for Primary Industries, while dietary supplements are the responsibility of Medsafe. And if that product contains a controlled medicine it is dealt with under the Medicines Act, but if the banned substance is covered by the Misuse of Drugs Act, then it becomes a police matter.
In the case of DMBA, it was the Psychoactive Regulatory Authority that stepped in as the substance is covered under the Psychoactive Substances Act.
It took the Herald less than two hours to obtain Frenzy and it was the Herald that commissioned the testing that saw the supplement banned.
That situation should change if the Government passes a bill that has been before Parliament in various guises since 2006. The latest version of the Natural Health and Supplementary Products Bill would create a regulatory authority to deal specifically with supplements. It would establish a system where products and their contents must be notified before going on sale. Breaches such as including prohibited ingredients, knowingly endangering public health or making unsubstantiated marketing claims would be dealt with with fines of up to $500,000 or prison sentences of up to five years.
Only New Zealand citizens would be able to notify products, making it harder for foreign suppliers to ship in products and avoid prosecution.
Until then, New Zealand's door remains open for the rogue traders who operate in the multibillion-dollar global supplement industry.
With brand names such as Hardcore Muscle Max and Life Extension, DHEA is billed as a muscle-building, youth-giving, naturally-occurring steroid hormone that will reinvigorate flagging sex lives.
Although it is banned in athletic competition, elderly Americans are free to ingest as much of the "dietary supplement" as they like. New Zealanders and Australians are not.
In Australia DHEA is classified as an "anabolic steroid or precursor" and is available only on prescription. In New Zealand DHEA - which is used in infertility treatment - can only legally be obtained via a doctor.
Customs officers regularly seize DHEA supplements at the border.
Figures released to the Herald under the Official Information Act reveal there have been 317 seizures since 2008 - and 49 in the first eight months of last year alone.
So what's the appeal?
According to the supplement sellers, allergies, arthritis, depression, emotional instability, fatigue, loss of libido, memory loss, stress and vaginal atrophy are just some of the symptoms that may be caused by DHEA deficiency.
Some studies also suggest low levels of DHEA might be associated with coronary heart disease in men, but other studies suggest the use of DHEA supplements may raise the risk of breast and prostate cancer, heart disease, diabetes, and stroke. They may also stimulate tumour growth in hormone-sensitive cancers.
The list of possible side effects include aggressiveness, irritability, sleeping trouble, the growth of body or facial hair on women, ceased menstruation, lower the levels of HDL ("good" cholesterol), acne, heart rhythm problems, liver problems, hair loss and oily skin.
Kiwis intent on finding out for themselves don't have to try their luck at the border, or so two sellers of a chemical cousin to DHEA known as 7-Keto will tell them.
The firms market 7-Keto as a version of DHEA that produces many of the same benefits. Neither company's marketing material mentions the potential side effects.
A spokesman for New Zealand's medicines regulatory body Medsafe said the legal status of DHEA 7-Keto was under review.iness.
