Key takeaways
- Wax at 15–25% gives structure; the blend decides glide and wear.
- Pour temperature within a 3-degree window prevents streaking and air bubbles.
- Shrink of 3–6% must be built into the fill weight.
A lipstick is a solid suspension of pigment in a wax and oil matrix, poured hot into a mould or a tube and cooled quickly. It looks like a cosmetic and behaves like a casting: the wax blend, the pour temperature and the cooling rate decide whether the bullet is smooth, whether it drags, and whether it breaks in a handbag.
1. The wax blend
Carnauba, candelilla and beeswax give structure; ozokerite and polyethylene give hardness and shine. A typical blend is 15 to 25 percent wax with 50 to 65 percent oils and 8 to 12 percent pigment. More carnauba gives a harder bullet that wears longer and drags more; more beeswax gives a softer bullet that feels creamier.
2. Oil phase
Castor oil is the traditional base because of its viscosity and pigment wetting. Esters and silicones improve glide and reduce the sticky feel. The oil phase determines how the pigment disperses and how the bullet feels for the first thirty seconds, which is when the customer decides.
3. Pigment and dispersion
Pigment at 8 to 12 percent is dispersed in part of the oil phase on a triple-roll mill before the wax is added. An undermilled pigment produces a grainy bullet and visible specks on the lip. The mill gap and the number of passes belong in the batch record.
4. Pour temperature
Pour at 5 to 10 degrees above the wax melting point, usually 75 to 85 degrees, and hold within a 3-degree window. Too hot and the pigment settles unevenly and the surface streaks; too cool and air bubbles form inside the bullet. A temperature-controlled pouring head is the difference between consistent and inconsistent output.
5. Cooling
Fast cooling in a chilled tunnel produces a smooth, slightly matte surface. Slow cooling produces a glossier surface and a softer core. The cooling profile also determines shrink, and shrink determines the visible gap between the bullet and the tube.
6. Shrink and fill weight
A poured lipstick shrinks 3 to 6 percent by volume as it solidifies. The fill weight must be set on the settled bullet, and the mould must be sized to allow for contraction. A brand that specifies the poured weight will ship a product that is short against the label claim.
7. The break test
Test ten bullets at 40 degrees for a week, then apply with normal pressure. A bullet that snaps at the base has too much wax or too little oil at the base; one that bends has too little structure. The fix is usually a small oil increase and a slower cooling ramp.
8. Wear and transfer
Wear is tested on panelists over four hours with a transfer score on a cup rim. A matte lipstick with high wax transfer less; a satin finish transfers more and is expected to. Matching the finish to the transfer promise is what prevents a one-star review about the mask.
9. Flavour and fragrance
Flavour at 0.2 to 0.5 percent is applied to the bullet surface or included in the formula. Surface application fades; inclusion affects the wax and can soften the bullet. Vanilla and mint are the most common, and both are allergens that must appear on the label in the EU.
10. Stability
A lipstick is tested at 40 degrees for twelve weeks and checked for sweating, bloom and odour. Sweating — oil appearing on the surface — comes from an imbalance between the oil phase and the wax. Bloom, a white film, comes from crystallising wax and is solved by a different wax blend rather than by more pigment.
11. Where it fits
Lipstick sits in the lipstick range; the mould question continues in the tooling entry.
Reference: Lipstick development and pour trials, 2025
