Quinine ascorbate is a salt of antimalarial drug quinine and ascorbic acid (vitamin C). Ascorbate reduces the potency of quinolone-containing anti-malarial drugs. Quinine ascorbate was marketed as a component of over-the-counter smoking deterrent products but was not recognized as safe by the FDA regulation in 1993.

Magnesium ascorbate is a non-acidic buffered form of Vitamin C and a source of the essential mineral Magnesium. The in vitro model system consisted of the isolated section of rat small intestine. The sources of magnesium ion (Mg2+) were magnesium chloride, magnesium sulphate, magnesium acetate, magnesium lactate, magnesium hydrocitrate and magnesium ascorbate. Magnesium ions from magnesium ascorbate were absorbed after the first 15 minutes to the highest extent of all salts, but after 120 minutes their absorption was the smallest of all. The use of magnesium ascorbate in food supplements may lead to an additional exposure to vitamin C and Magnesium.

Erythorbic acid, an epimer of L-ascorbic acid, is used in the United States as a food additive. It was studied, that erythorbic acid enhanced of iron absorption and could play a major role in enhancing iron bioavailability from mixed diets that include foods preserved with erythorbic acid. In addition, was investigated if the erythorbic acid could influence on the metabolism of vitamin C in young women, and obtained results showed, that prolonged ingestion of erythorbic acid had no effect on vitamin C uptake or clearance from the body.

Furfural (also called 2-formylfuran, furan-2- aldehyde, 2-furancarboxaldehyde, 2-furyl-methanal, pyromucic aldehyde, 2-furanaldehyde, 2-furancarbonal, carboxylic aldehyde, furan-2-carbaldehyde, furancarbonal, 2-furaldehyde, or 2-furfural), contains a heteroaromatic furan ring and an aldehyde functional group. Furfural was first isolated in 1832 by J.W. Döbereiner, and has been industrially produced since 1922. Today, furfural is used for multiple purposes, for example as a selective extraction agent (in the recovery of butadiene from oil steam cracking or in the refining of petroleum, diesel fuels, lubricants and vegetable oils), as a solvent (for anthracene or resins), as an agent for vulcanization, as a nematicide and fungicide, as a flavoring agent in a variety of food products and alcoholic and non-alcoholic beverages, and as a component of commercial herbicides, insecticides, pesticides, antiseptics, disinfectors, and rust removers. Furfural is also involved in the manufacture of pharmaceuticals, cosmetics, fragrances, flavors and resins (in this latter case, by condensation with phenol, formaldehyde, acetone, or urea, to produce thermosetting resins with extreme physical strength); as well as in other products such as household cleaners and detergents. Furfural occurs naturally in some fruits and vegetables. It can be formed in other foods during cooking, and is present in wood smoke. Furfural is an ingredient contained in many fragrances and flavours. It may be found in fragrances used in decorative cosmetics, fine fragrances, shampoos, toilet soaps and other toiletries, in flavours of oral care products as well as in non-cosmetic products such as household cleaners and detergents. Furfural in the in the fragrance compound is reported to be 0.036% or less. The European Commission received a submission from the European Flavour & Fragrance Association with data supporting the safe use of Furfural as a fragrance ingredient. The predominant pathway of metabolism of Furfural in humans is oxidation of the aldehyde to yield furoic acid, which may either conjugate with amino acids or condense with acetyl coenzyme A to produce the furanacrylic acid. Furfural is a carcinogen classified in EU as a Category 3 carcinogen. Furfural was tested for carcinogenicity by oral administration in one study in mice and one study in rats. In mice, it increased the incidence of hepatocellular adenomas and carcinomas in males and of hepatocellular adenomas and forestomach papillomas in females. Male rats had a low incidence of cholangiocarcinomas, which occur rarely. In a two-stage assay on mouse skin, Furfural had weak initiating activity. On the basis of quantitative risk assessment it is concluded that Furfural at the maximum exposure stated by RIFM does not represent any significant cancer risk. However, the exposure should not be increased.