The verdict comes from a senior judge presiding at a hearing at the European Court of Justice in Luxembourg in January.
Two parallel cases brought by trade associations (the Health Food Manufacturers Association and the National Association of Health Stores) and a consumer health campaign group, the Alliance for Natural Health (ANH), argued that the directive infringes EU constitutional law and basic principles of free trade.
The supplement industry, particularly in the UK, Ireland and the Netherlands, will see the removal of hundreds of ingredients widely used products on these markets and is also expected to reduce levels of vitamins and minerals permitted in the UK from current levels.
Although not final, the Advocate-General's opinion can be influential on the rest of the European judges, who will deliver their ruling in June.
According to the groups bringing the case, they received little opposition at the hearing, hinting at a positive outcome for industry. However challenges to EU directives are extremely rare.
In the meantime, they continue to work on making the dossier submission procedure easier for industry. At a recent meeting with Lord Warner, the UK's Parliamentary Under Secretary of State for Health, HFMA chairman Peter Aldis, and other interested parties, pressed for increased resources from the FSA and government support for 'light' dossiers being submitted to the European authorities.