The Ingredients: Origins, Chemistry and the State of the Research

Vitamin C — 40 mg per daily dose

The story of ascorbic acid begins in 1747 aboard HMS Salisbury, where the Scottish naval surgeon James Lind divided twelve sailors into six treatment groups — one of the earliest controlled clinical trials we know of. The substance itself wasn’t isolated until 1928, when Albert Szent-Györgyi obtained it from adrenal cortex and later from paprika, which won him the 1937 Nobel Prize in Medicine. Chemically, L-ascorbic acid is an electron donor that acts as a cofactor in hydroxylation reactions, among them prolyl-4-hydroxylase and, of interest here, the body’s own synthesis of L-carnitine. It enters the bloodstream through a family of saturable sodium-dependent transporters, the SVCTs, which makes both absorption and elimination strongly dose-dependent. Lykkesfeldt & Tveden-Nyborg (Nutrients, 2019) set these kinetics out in detail, including the point at which the pharmacokinetics shift from zero to first order, and the spread of tissue concentrations at homeostasis — from around 0.2 mM in muscle and heart up to 10 mM in brain and adrenal gland.

Vitamin B3 (nicotinamide) — 20 mg per daily dose

Between 1914 and 1929, the physician Joseph Goldberger travelled through the American South investigating pellagra, and showed that it wasn’t an infectious disease at all — against the scientific consensus of his day. The missing factor was identified in 1937 by Conrad Elvehjem, who isolated nicotinamide from liver. Nicotinamide is a precursor of NAD⁺, one of the most heavily used coenzymes in human metabolism. Bogan & Brenner (Annual Review of Nutrition, 2008) weighed up the various NAD⁺ precursors — nicotinic acid, nicotinamide and the then newly identified nicotinamide riboside — and note that baseline requirements for NAD⁺ synthesis can be met either with dietary tryptophan or with less than 20 mg of niacin a day.

Zinc — 7 mg as citrate per daily dose

Zinc was only recognised as essential to humans in 1961, when Ananda Prasad described patients with marked zinc deficiency in Iran and, shortly afterwards, in Egypt. More than three hundred zinc-dependent enzymes are known today, along with the zinc finger motif that lets a large number of human transcription factors bind to DNA. The form matters here, and MS Spray uses citrate: Wegmüller et al. (The Journal of Nutrition, 2014) used a double-isotope tracer method with ⁶⁷Zn and ⁷⁰Zn to measure absorption from 10 mg of zinc in 15 healthy adults, in a randomised, double-masked, three-way crossover. Median fractional absorption came out at 61.3 % from zinc citrate and 60.9 % from zinc gluconate, with zinc oxide significantly lower at 49.9 %.

L-Carnitine — 20 mg per daily dose

Vladimir Gulewitsch and Rudolf Krimberg isolated the substance from muscle extract in 1905. The name comes from the Latin carnis. The human body makes L-carnitine itself, from the amino acids lysine and methionine, with vitamin C and iron required as cofactors — one of the few places where two of the ingredients in this formula are biochemically linked. Inside the cell, carnitine plays a part in transport across the inner mitochondrial membrane. Rebouche (Annals of the New York Academy of Sciences, 2004) pulled together the pharmacokinetics: bioavailability of dietary L-carnitine runs at 54–87 % and depends on how much is in the meal, whereas absorption from supplements of 0.5 to 6 g is largely passive, at 14–18 % of the dose. Whatever isn’t absorbed is mostly broken down by microorganisms in the large intestine.

L-Citrulline — 20 mg per daily dose

In 1914 the Japanese chemists Koga and Odake isolated an unknown amino acid from watermelon juice; Wada named it in 1930, after Citrullus lanatus, the watermelon. L-citrulline is one of the non-proteinogenic amino acids, meaning it doesn’t appear in any human protein; it works as an intermediate in the urea cycle instead. Its pharmacokinetics are unusual: it passes through the liver largely unchanged and is only converted to arginine in the kidney. Moinard et al. (British Journal of Nutrition, 2008) ran what became known as the Citrudose study — eight fasting healthy men took four separate oral loads of 2, 5, 10 and 15 g in random order, with blood drawn ten times over eight hours. Of the plasma amino acids measured, only citrulline, ornithine and arginine shifted, and none of the men reported side effects at any of the four doses.

L-Glutamine — 20 mg per daily dose

Of all the amino acids, glutamine is the one that occurs most abundantly in free form in blood plasma and skeletal muscle. It carries nitrogen between tissues and supplies precursors for nucleic acids, nucleotides and amino sugars. Its most interesting mark on nutritional science is a conceptual one: it was glutamine that gave rise to the idea of the conditionally essential amino acid — a substance the body normally makes in sufficient quantity, but perhaps not under sustained physiological stress. Lacey & Wilmore (Nutrition Reviews, 1990) raised the question in what has since become a classic paper, framing it around the critically ill, where requirements may outrun the body’s own production. It’s still debated.

Vitamins B1, B2, B5 and B6 — four precursors, four coenzymes

These four sit together for a reason: each one is converted into a coenzyme. Thiamine (1.1 mg) becomes thiamine pyrophosphate — discovered through the beriberi work of the military physician Christiaan Eijkman in Java, the same work that led Casimir Funk to coin the word “vitamine” in 1912. Riboflavin (1.4 mg) owes its name to its colour, flavus, yellow; it goes on to form FMN and FAD, the flavoenzymes of the respiratory chain. Pantothenic acid (6 mg) takes its name from the Greek pantothen, “from everywhere”, because Roger Williams found it in 1933 in almost every tissue he examined — it forms the backbone of coenzyme A. Pyridoxine (1.4 mg), described by Paul György in 1934, becomes pyridoxal-5-phosphate, the coenzyme for more than a hundred enzymes of amino acid metabolism. Depeint et al. (Chemico-Biological Interactions, 2006) reviewed how thiamin, riboflavin, niacin, pantothenic acid and biotin each hold up mitochondrial energy metabolism; pyridoxine, folate and B12 were dealt with separately, in a companion paper in the same issue.

Folic acid and vitamin B12 — 200 µg and 2.5 µg per daily dose

The British physician Lucy Wills, working in Bombay, described in 1931 a dietary factor found in yeast extract; it was later named after folium, the leaf from which it was first isolated. Two research groups isolated vitamin B12 almost simultaneously in 1948, and Dorothy Hodgkin resolved its structure by X-ray crystallography in 1956 — work that earned her the 1964 Nobel Prize in Chemistry. B12 is the only vitamin with a metal atom at its centre, namely cobalt, and the only one whose absorption requires a dedicated carrier protein. The two are biochemically tied to each other: methionine synthase needs folate and B12 together. On bioavailability, Winkels et al. (American Journal of Clinical Nutrition, 2007) settled a long-running question in a four-week intervention with 72 healthy adults: folates from fruit, vegetables and liver came out at roughly 80 % of the bioavailability of synthetic folic acid — 78 % by ¹³C-labelled folate, 85 % by the change in serum folate.

Biotin — 50 µg per daily dose

Biotin came to light by a roundabout route: rats fed nothing but raw egg white developed changes to skin and coat. The culprit was avidin, a protein in egg white that binds biotin so tightly the body can’t use it. Fritz Kögl crystallised the substance from egg yolk in 1936 and Vincent du Vigneaud resolved its structure in 1942. In the body, biotin works as a cofactor for the carboxylases. One observation from laboratory medicine has real practical consequences: very high biotin intakes, in the milligram range, can interfere with certain immunoassays. At 50 µg, the amount in MS Spray, that doesn’t come into play. Zempleni & Mock (American Journal of Clinical Nutrition, 1999) gave six healthy adults biotin orally and intravenously in a crossover design and concluded that oral biotin is completely absorbed even at pharmacologic doses — though those doses ran from roughly 0.5 to 20 mg, well above the amount here.

What this research supports — and what it doesn’t

Ten of the thirteen ingredients are vitamins and minerals for which authorised health claims exist; three of those are quoted in their official wording on the MS Spray home page. For L-carnitine, L-citrulline and L-glutamine there are no authorised health claims — not in Great Britain and not in the EU. The work cited here describes what those three substances are: where they come from, how they travel through the body, how well they’re tolerated. It says nothing about MS Spray, and nothing in it tells you what this product does.

A second point is worth making just as plainly. The studies cited on the three amino acids work with amounts in the gram range. MS Spray contains 20 mg of each per daily dose. That’s a different order of magnitude, and we’d rather put it in front of you than gloss over it.