L-Arginine: dubious supplement marketing

It's a recurring theme that once some biochemical is shown to have a useful or even vital role in the body, someone will produce a supplement and market it on the woo logic that if something is good for you, lots of it will be even better. This is patently nonsense: vitamins, for instance, are crucial to health but are toxic in high doses (as, famously, the explorer Douglas Mawson found out afer eating husky liver). It's even more nonsense in the case of the body's neurotransmitters and other signalling chemicals, which work on specific concentrations. Get the wrong level of dopamine, say, and you'll get radical neurological problems (again famously, as documented by Olive Sacks in Awakenings) But this doesn't matter to supplement promoters: the more you take, the merrier.
      I noticed this syndrome recently in the marketing of L-Arginine. The 1998 Nobel Prize in Physiology or Medicine was awarded to Furchgott, Ignarro and Murad "for their discoveries concerning nitric oxide as a signalling molecule in the cardiovascular system". Nitric oxide, they discovered, turns out to have a crucial role in various functions: blood pressure control, heart action, neurosignalling in relation to the gastronintestinal tract and memory formation,, as a biocide in the immune system, and in penis erection. It's synthesised in the body by an enzyme, nitric oxide synthase, acting on a common amino acid L-arginine, which is actually nonessential, as it's synthesised in the body.
      Given this role, it can easily be imagined that levels are critical. The vascular damage seen in diabetes appears to be down to low levels; conversely, the lethal shock seen in severe infections is down to overproduction of nitric oxide. The precursor to the nitric oxide, L-arginine, may itself be a double-edged sword: one study at Johns Hopkins had to be brought to a halt on safety concerns after L-arginine supplements appeared to worsen the risk of death in patients recovering from heart attack (see L-arginine Supplements Linked to Increased Risk of Death in MI Patients). What's the response of supplement vendors to this complex situation? Take moar L-arginine!

Bearing that in mind, about a week back I saw in the Exeter Express & Echo featured a story, Firm promotes body products: "A company specialising in offering a new dietary supplement range has a promotion in Exeter tomorrow.The founders of Arkworld claim their products can reverse biological age and repair, restore and rejuvenate the body through circulation". Arkworld is fairly ghastly in four respects. One, it's a multi-level marketing scheme. Two, it's designed around some laboured Biblical metaphor: "Everything we do as a company is going to be built around the Ark Story". Three, bad puns on the word Ark ("The Marketing Plan or should we say, Arketing Plan"). Four, the simplistic assumption that guzzling L-arginine is automatically good for you.
      Needless to say, their ADNO – Arginine Derived Nitric Oxide page doesn't tell you we synthesise our own ("Your body uses Arginine an Amino Acid we absorb from food") and simply asserts that more of it makes everything work better in all the systems where nitric oxide is involved. And that, of course, is achieved via two arginine supplements, Ark1 and Ark2, as well as the PINKDrink.
      The PINKDrink website makes a number of grandiose claims. "Nitric Oxide is referred to by scientists as the 'Miracle Molecule'" (nope: only on sites selling L-arginine supplements such as miraclemolecule.co.uk - and it needs to join the queue behind phosphatidylcholine, water, P57, DMT, melatonin, omega-3 and no doubt many more). "Arkworld's products have been created by leading scientists and product formulators, including the legendary Jeff Golini who cracked the Creatine Code". Legendary where? Apparently only on sites selling his body-building product Kre-Alkalyn, and for some reason this groundbreaking work doesn't appear in PubMed. Golini is one of the group behind Arkworld, listed as doctors though rather than medical doctors the group appears to be a mix of technical and marketing people headed by a dentist and a naturopath. As leading scientists, it's remarkable how few Google hits they get.
      The site also mentions the PINKDrink appeared on the BBC's Inside Out, which may be true but if you watch the clip from this episode about CADASIL sufferer Jack Shields, its role is fairly subliminal, as a brief glimpse of some powder said to be L-arginine. There's also an interesting factoid that "Columbia University refers to L-arginine as the 'magic bullet' for the cardiovascular system. Over 10,000 L-arginine citations were compiled by Columbia University researchers in their quest to document the clinical benefits of this simple amino acid". I have been unable to find a citation for this claim.

Addendum: if you want to comment, read the comments policy first. If you have actual evidence that I'm wrong - peer-reviewed research - by all means comment.  But I will bin any comments that just tell me I'm wrong and link to some promotional/sales website.