Every time you open a bottle of nail polish, you are holding one of the most chemically complex products in the beauty industry. Seriously—a nail polish formula is technically closer to automotive paint than to a face cream. There is no water, no emulsifiers, and none of the usual cosmetic logic. Instead, there are volatile solvents, polymer film-formers, and a plasticization system that has been developed over decades. And that is precisely why "simply making polish at home" is a task that stumps even experienced formulators.
What is nail polish from a chemical perspective
Nail polish is an anhydrous suspension of pigments and pearlescent particles in a polymer solution. When you apply it to the nail, the solvent evaporates, and the polymers form a hard, flexible film. It sounds simple. In practice, it is a balancing act between a dozen competing requirements: the film must be hard but not brittle; flexible but not sticky; shiny but not cloudy after a week.
Fundamentally, nail polish differs from everything we usually discuss in the context of homemade cosmetics. If you have read our article on anhydrous products, you know that the absence of water changes the rules of the game on its own. But nail polish goes further—there are no oils, waxes, or typical emollients here. Only polymers, solvents, and functional additives.
Key components of the formula
A classic polish formula is built around four functional groups:
- Film-formers — create the film itself. Historically, this is nitrocellulose, and it remains the standard to this day. It is what provides that characteristic shine and hardness.
- Resins — improve adhesion to the nail and shine. Tosylamide/Formaldehyde Resin was the main one before the wave of "3-Free" formulas; now it is being replaced by polyester resins or acrylates.
- Plasticizers — prevent cracking. Dibutyl phthalate (DBP) and camphor are classics, although the former has almost disappeared from the market. Triethyl citrate and acetyl tributyl citrate (ATBC) are modern alternatives.
- Solvents — keep everything in a liquid state until application. Ethyl acetate, butyl acetate, and isopropyl alcohol are a typical mixture.
Why nitrocellulose still rules
Nitrocellulose is a modified cellulose treated with nitric acid. Yes, the very same alkali and acid from your high school chemistry course, just on an industrial scale. The resulting polymer forms a film with a unique combination of hardness and transparency that no “green” alternative has yet been able to fully replicate. This is precisely why even the most “clean” brands usually still use nitrocellulose — they just stay quiet about it in their marketing materials.
Plasticizers: why the film shouldn't be like glass
If nail polish consisted only of nitrocellulose and a solvent, once dry, you would be left with a brittle crust that cracks at the slightest movement of your finger. Plasticizers solve this problem — they embed themselves between the polymer chains and lower the glass transition temperature, making the film flexible.
The scandal surrounding phthalates
Dibutyl phthalate (DBP) was the standard plasticizer in nail polishes for decades. Then, studies emerged pointing to its potential as an endocrine disruptor, and the era of “3-Free” (free from DBP, toluene, and formaldehyde) began, followed by “5-Free”, “7-Free”, “10-Free”, and so on. The marketing logic here is clear, but the chemical logic is not always so. Some of the “excluded” ingredients were not even used in modern formulas, yet their absence from the list is turned into an advertising argument.
The real alternative to DBP today is triethyl citrate and acetyl tributyl citrate (ATBC). Both are biodegradable, and both demonstrate a good safety profile. The trade-off is a slightly softer film and a somewhat different drying time.
Camphor: an old player with a new reputation
Camphor is a natural plasticizer that has been used in nail polishes since the very beginning of the industry. It is volatile, so it partially evaporates along with the solvents, but a portion remains in the film to provide flexibility. Its downside is its characteristic odor, which not everyone is sensitive to, but those who are know it well.
Solvents: what evaporates and where it goes
A typical nail polish formula contains 60–70% solvents by weight. That is not a typo. This is precisely why nail polish dries — the solvents fly off, leaving only the polymer film and pigments behind.
The solvent blend is no accident
Butyl acetate and ethyl acetate evaporate at different rates. This is crucial: if the solvent evaporated instantly, the polish would dry while still on the brush. If it evaporated too slowly, you would be waiting for an hour. Formulators select the blend to achieve the necessary “application window” — the time when the polish is still fluid and self-leveling, but already viscous enough not to run.
Isopropanol is added in small amounts — it helps dissolve certain resins and regulates viscosity. Toluene was previously the primary solvent due to its excellent dissolving power, but its toxicity has led to its disappearance from most modern formulas.
Pigments and pearlescence: why color is a science in itself
Pigments in nail polish are not just "paint." They must be compatible with solvents (not dissolving in them, but rather dispersing), stable to UV radiation, and non-reactive with polymers. This narrows the list of permissible colorants down to a few dozen.
Approved pigments for nails
Regulatory requirements for nail pigments are stricter than for facial skin because the nail is a semi-permeable structure. A typical list includes:
- Iron oxides (CI 77491, CI 77492, CI 77499) — red, yellow, black
- Titanium dioxide (CI 77891) — white, the base for pastel shades
- Ultramarine (CI 77007) — blue
- Mica coated with metal oxides — pearlescent effects
- Organic pigments such as D&C Red No. 7 — bright, saturated colors
The pearlescent effect is created by mica particles coated with thin layers of titanium dioxide or iron oxide. Light interference on these layers produces the iridescence. The particle size determines the nature of the pearl: fine particles create a satin sheen, while larger ones create a holographic effect.
Why red polish is more complex than black
Red shades are technically the most temperamental. Organic red pigments are often unstable to UV and fade. Iron oxides produce a "muddy" red. Formulators usually combine several pigments to achieve the desired shade with sufficient stability — and this explains why two "red" polishes from different brands look completely different after a month of use.
Gel and "long-wear" formulas: what is the difference
Classic nail polish and gel polish are fundamentally different systems, even though they look similar. Gel polish contains photoinitiators and acrylate monomers that polymerize under a UV/LED lamp. This is not "drying" — it is a chemical cross-linking reaction. This is precisely why gel polish does not wash off with acetone as easily as regular polish: it literally has a different molecular film structure.
"Long-wear" regular polishes are a marketing category. In reality, they differ from standard ones by having a higher resin content (improved adhesion) and specific plasticizers. There is no magic — just a better-optimized formulation.
The connection to soap making: an unexpected angle
It would seem, what do nail polish and soap have in common? In reality, the principle of how alkali works in chemical reactions unites many cosmetic processes. In soap making, alkali (sodium or potassium hydroxide) breaks down oil triglycerides through saponification. In the production of nitrocellulose, nitric acid modifies cellulose. Both processes are chemical transformations of natural raw materials into functional polymers. If you are interested in this logic, take a look at our detailed material on the chemistry of handmade soap — these parallels are particularly clear there.
Formulating polish at home: an honest conversation about the possibilities
Is it possible to make nail polish at home? Technically, yes. Practically, it is one of the most complex DIY projects in cosmetics, and here is why:
- Nitrocellulose is a flammable substance that requires special storage conditions
- Working with volatile solvents requires ventilation and respiratory protection
- Dispersing pigments without industrial equipment results in uneven color
- Adjusting the solvent ratio for the desired viscosity is an iterative process involving dozens of trials
- Suspension stability (ensuring pigments do not settle or agglomerate) is a separate challenge
This does not mean "don't try." It means: enter with an understanding of the scale of the task. The starting point is ready-made bases for customization (tinted bases), to which you only add pigments. This removes the most difficult part and allows you to focus on color and effects.
Understanding the chemistry of formulas — whether it's polish, cream, or shampoo — is built on the same principles. If you are interested in delving deeper, see what the Walker Formulation Academy Club has to offer — it features breakdowns of formulas for completely different product categories.
Why does nail polish dry faster when blown with air?
Solvent evaporation is a diffusion process. A layer of saturated vapor forms above the surface of the polish, which slows down further evaporation. Blowing air constantly removes this layer, and the solvent evaporates faster. This is precisely why a hair dryer on a cool setting speeds up drying, while hot air does not: it increases the viscosity of the solvent but does not improve diffusion as effectively.
Why does nail polish thicken in the bottle and how can it be fixed?
Solvents evaporate through the cap and the bottle threads even when closed — it is a slow but inevitable process. The concentration of polymers increases, and the viscosity rises. Special nail polish thinners contain a mixture of ethyl acetate and butyl acetate in the correct ratio. Regular acetone is not suitable: it dissolves nitrocellulose too aggressively and disrupts the balance of the polymer system.
Are there truly "natural" nail polishes?
As of now, no, not in the full sense of the word. There are formulas based on biodegradable solvents (for example, ethyl lactate derived from corn) and natural resins (shellac), but nitrocellulose remains an almost indispensable component for normal wear. Brands that claim a "100% natural" composition usually use nitrocellulose (which technically comes from cotton or wood) and consider this sufficient grounds for "natural" positioning.
The chemistry of nail polish is a reminder that cosmetics are never "just beautiful." Behind every shiny coating lies an engineering solution: how to keep the pigment in suspension, how to make the polymer lay down evenly, and how to balance the hardness and flexibility of the film. The same questions — just on different scales — face the formulator of a cream, shampoo, or any product where pH is important. The logic is the same, the details are different. This is exactly what makes cosmetic chemistry an infinitely interesting field.
If you want to learn how to formulate — from basic emulsions to complex anhydrous systems — we have a course. Take a look at the home page to see what is currently available.
