Decyl cocoate Gentle cleansing agent created from coconut oil reacting with an ingredient from coconut called decanol. Non-toxic and non-irritating, which is why it’s being increasingly used in natural bodycare.

Decyl glucoside See above, but in this case, from elements in corn. Allowed under organic guidelines.

Dehydroacetic acid A synthetic fungicide and bactericide which is not allowed to be used in aerosol products, and only in very small concentrations. However, as this is a preservative – and only used in the teensiest amounts – it’s classified as a low ‘hazard’ in the Environmental Working Group’s Cosmetic Safety Database.

Dextrin A white powder also known as Starch gum or British gum; used in cosmetics as a thickener. In some people, it can trigger an allergic reaction.

Dextrin palmitate A semi-synthetic ingredient used as a thickener and emulsifier. (NB Be aware that some palmitates have been linked with contact dermatitis.)

Diazlolidinyl urea A semi-synthetic or synthetic antiseptic and deodoriser, which is also used as a preservative against bacteria and fungi. It may be a mild cumulative skin irritant in humans, and may release Formaldehyde, in some circumstances.

Dicaprylyl carbonate Comes from Carbonic acid and Caprylyl alcohol, and is used in sunscreens, age-defying creams and also in treatments for redness and rosacea.

Dicaprylyl maleate From Caprylyl alcohol and Maleic acid (which is a preservative for fats and oils, and also a pH adjuster). Used in all sorts of cosmetics products from turn-back-the-clock ‘miracle’ creams to acne treatments.

Dichlorobenzyl alcohol A synthetic preservative – see also Benzyl alcohol under ‘B’ – here.

Diethylhexyl succinate Also known as Succinic acid or Butanedioc acid; occurs in fossils, fungi, etc. and is used as a germicide and also a fragrance ingredient. This has been classified as a low ‘hazard’ in the Environmental Working Group’s Cosmetic Safety Database.

Dihydroxyacetone Also known as DHA. This ingredient – generally obtained by the action of particular bacteria on glycerol (from sugar) – is found in most fake tans, and is used to turn skin brown – although this reaction provides no natural protection from UV rays, unlike a real tan. It works by reacting with amino acids found in the skin’s epidermal layer. Can be sensitising for some users.

Diisostearyl malate Derived from a combination of Isostearyl acid and Malic acid (an AHA ‘fruit acid’ from apples). We’re trying to find out more about this ingredient because it’s not widely used and info is elusive; however, we can tell you it’s c lassified as a low ‘hazard’ in the Environmental Working Group’s Cosmetic Safety Database, but that’s partly due to lack of available data (as we found!) Only used in teensy quantities, though.

Dimethicone A synthesised silicone fluid which is used as a base in creams and ointments, and helps to create a silky feel; it’s also designated as safe for use in food, with very low toxicity.

Dimethicone/vinyl dimethicone crosspolymer See above; however, not approved as a food additive.

Dimethiconol An anti-foaming and skin conditioning ingredient (used in blushers, moisturisers etc.) which is very similar to Dimethicone, see above.

Dimethiconol meadowfoamate See above, but derived from Meadowfoam (as the name suggests!)

Dipalmitoyl hydroxyproline A fatty ingredient made with amino acids, and derived from plants such as palm oil. Said to have anti-ageing properties.

Dipentaerythrityl hexahydroxystearate/hexastearate/
hexarosinate A mix of an extract of algae and Rosin (from pine trees), to create an ingredient used in many make-up items, including lipstick, eyeliner, concealer, blusher etc.

Dipentene (D-Limonene) Naturally occurring in star anise, caraway, celery, oranges, cumin, fennel, marigold and more, this compound has to be listed on labels because it is one of the most common allergens.

Dipotassium glycyrrhizate A salt derived from Glycyrrhizic acid, extracted from Licorice.

Disodium cocoamphodiacetate A foaming agent derived from coconuts, used as a dispersant and surfactant; can be irritating to eyes (like many foaming ingredients).

Disodium cocoyl glutamate Considered to be a very gentle detergent for skin and hair, derived from coconut oil and fermented sugar; environmentally-friendly and well-tolerated by allergic skintypes. It’s approved for use by the European organisation BDIH, which certifies ‘naturalness’ in cosmetics.

Disodium EDTA This synthetic ingredient is used to help adjust the viscosity of a product, and to stabilise; there are some concerns because it seems it may alter skin’s structure, allowing easier penetration of other ingredients.

Disteardimonium hectorite This is what’s known as a ‘Quaternary ammonium compound’: a wide family of preservatives, germicides and antiseptics, in this case created by a reaction with hectorite (a mineral). Diluted solutions are used in medicine to sterilise skin. Used as a ‘suspending agent’, often with pigments.