DPG, IPM, MCT and TEC Compared: Which Solvent/Carrier and When?

There are four carriers whose names come up most often in the perfumery and cosmetics workshop: DPG (dipropylene glycol), IPM (isopropyl myristate), MCT (medium-chain triglyceride oil) and TEC (triethyl citrate). They all sit on the "diluent" shelf, yet none of them is a substitute for any other. One opens up the scent, one glides on skin, one carries an oil base, one holds up inside soap.

First, let's correct a misconception: these four are not fixatives. IPM and glycols slow the evaporation of alcohol slightly, which creates a feeling of "extended longevity" — this is a volatility-modulating effect, not fixation. True fixatives are macrocyclic musks, heavy balsams and resins, and Glucam-type glucose ethers. Keep this distinction in mind when labelling.

One more safety note: longevity depends on volatility, not concentration. The right carrier shapes how the scent is released and how it feels on skin; it does not sell "long life" on its own. The rest lies in the structure of the formula.

What sets each one apart is its molecular character. Polarity, viscosity, its own odour and what it can dissolve — these factors drive the choice.

DPG (dipropylene glycol): A medium-viscosity glycol that is miscible with water and alcohol and can be considered odourless. It is the most widely used carrier in fragrance concentrates and room fragrance bases. It is also the backbone of alcohol-free fragrance oil bases. You will reach for our DPG product frequently in workshop formulas.

IPM (isopropyl myristate): An emollient that is slightly oily yet lightweight and spreads quickly on skin. It shines in oil-based fragrances and products where a "dry-touch" feel is desired. It is insoluble in water but compatible with alcohol and oils. If you use it at high levels, don't overlook the risk of staining fabrics.

MCT (medium-chain triglyceride): A clear, oxidation-resistant carrier oil derived from coconut. It is a favourite for roll-on oil fragrances, massage oils and skin oils. It is far more stable than natural oils and has a neutral odour.

TEC (triethyl citrate): An ester of citric acid. It imparts a mild fixation feel, supports clarity in alcohol-based formulas and is a popular choice in deodorant and antiperspirant bases. Slightly oily but not tacky.

Placing them in the same frame makes the differences clear. The values below are typical ranges; your supplier's technical data sheet (TDS) always takes precedence.

Note: the density difference can cause problems at the filling stage. TEC is close to 1.14 g/ml while IPM is around 0.85. 100 g of IPM occupies approximately 118 ml; 100 g of TEC occupies only 88 ml. If you are filling by volume (ml), account for this difference — otherwise your bottle will either overflow or come up short.

The right carrier flows from the character of the product you want to make. The steps below simplify the decision.

There are three mistakes we encounter most often at the bench: choosing the wrong polarity and ending up with a cloudy product, forgetting density and overfilling a bottle, and treating the carrier as a "fixative" and expecting performance it cannot deliver.

Cloudiness (louching) warning: In an alcohol-based formula, as the water content increases, aroma molecules that are insoluble in water precipitate and cause cloudiness. Water does not prevent this — it triggers it. The purpose of water is to soften the initial sharpness of the alcohol and open up the scent. Start with a small amount of water, test for clarity, and switch to a dedicated perfumer's alcohol if needed.

Maturation: Carry out maceration at room temperature (~15–20 °C) and in the dark — reactions slow down in the cold. Chilling and filtration is a separate, subsequent step; it is used to precipitate and filter out waxy components. Find the details in our maceration duration comparison.