Luxembourg is unusual: it does not maintain its own list of permitted substances and maximum doses for food supplements. Its food safety authority says plainly that lists drawn up in other EU member states serve as the reference for Luxembourg's competent authorities. That leaves melatonin without a Luxembourg number.

We would rather set out the awkward part than leave it. Luxembourg's neighbours disagree sharply - Belgium caps melatonin at 0.3 mg, France allows up to 2 mg - and the melatonin supplements we can see on Luxembourg pharmacy shelves are formulated at 0.29 mg, which is the Belgian figure. Higher doses appear in Luxembourg as over-the-counter medicines rather than as supplements. We cannot rule out that a Luxembourg assessment would reach for the Belgian number, in which case our 1 mg would be over it.

We have found no Luxembourg enforcement against melatonin supplements at any dose, and no Luxembourg rule that our product breaches. That is the basis on which we currently ship. We are putting the question to the Luxembourg authorities directly, and we will say so here when we have an answer.