What's Really in Your Nail Products? A Guide to Common Ingredients

If you've ever squinted at an ingredient list on an SDS and felt completely lost, you're not alone. Nail product formulations can look like a chemistry exam — but once you understand the key players, it all starts to make a lot more sense.

This guide breaks down the most common ingredients found in professional gel polishes and builder gels, what they actually do, and what to watch out for.

The Methacrylate Family

The backbone of most professional nail products is the methacrylate and acrylate family. These are the monomers and polymers responsible for adhesion, flexibility, and durability. Think of them as the building blocks that hold everything together.

Acrylates Copolymer is one of the most widely used ingredients across the industry — including in Planet Nails gel polishes. It's a film-forming polymer that gives gel polish its structure and wear. On its own it's considered low-risk, and it's found in everything from nail products to cosmetics.

HEMA (2-Hydroxyethyl Methacrylate) is probably the most talked-about ingredient in the nail world right now. It's excellent at bonding to the natural nail, which is why it's been used in gel formulas for decades. The issue is that with repeated skin contact — particularly from undercured product — some people develop a sensitisation reaction. Once sensitised, a person can react to HEMA and related methacrylates for life. This is why proper application technique matters so much: keep product off the skin, cure thoroughly, and wear gloves where appropriate.

Di-HEMA is a related molecule sometimes used as an alternative. It has similar bonding properties but a slightly different sensitisation profile. It is not automatically 'safer' than HEMA — it's simply different, and reactions are still possible.

HPMA (2-Hydroxypropyl Methacrylate) is another methacrylate variant sometimes marketed as a HEMA-free alternative. However, it belongs to the same chemical family and carries similar sensitisation risks. If a client has a known methacrylate sensitivity, HEMA-free doesn't necessarily mean reaction-free.

EMA (Ethyl Methacrylate) is the standard monomer used in professional acrylic liquid. It replaced MMA decades ago and is considered safe for professional use when handled correctly.

MMA (Methyl Methacrylate) is the one to know about and avoid. It's banned for use in nail products in many countries, including the USA, due to serious health and nail damage risks. None of the Planet Nails products contain MMA. If you're ever offered an acrylic liquid at a suspiciously low price, checking for MMA is the first thing to do.

Photoinitiators

Photoinitiators are the ingredients that respond to UV/LED light and trigger the curing process. Without them, your gel simply wouldn't harden.

TPO (Trimethylbenzoyl Diphenylphosphine Oxide) and its variants are among the most common photoinitiators in professional gel products, including Planet Nails gel polishes. They're highly effective with modern LED lamps and well-studied in terms of safety at the concentrations used in cosmetic formulations.

2-Isopropyl Thioxanthone (ITX) is another photoinitiator used in some formulations. It works at slightly different wavelengths, which is one reason why using the correct lamp for your products always matters — not all photoinitiators respond equally to all lamps.

Other Common Ingredients

Dimethicone is a silicone-based ingredient that improves texture, slip, and application. It's found in a huge range of cosmetics and is considered very safe. You'll find it in Planet Nails gel polishes as a small percentage of the formula.

Pentaerythritol tetra(3-mercaptopropionate) is a thiol-based crosslinker used to improve flexibility and adhesion in gel systems. It sounds alarming but is a well-established cosmetic ingredient.

Microcrystalline Wax is sometimes used in painting gels and colour gels to adjust viscosity and texture. It's inert and low-risk.

Pigments and Colourants — titanium dioxide (for opacity and white shades), and various CI-numbered pigments for colour — are standard cosmetic-grade colourants. They're tightly regulated in the EU and USA, which is part of why sourcing from those markets matters.

What This Means in Practice

Understanding ingredients isn't just interesting — it's part of being a professional. A few key takeaways:

• Sensitisation is cumulative and permanent. The biggest risk with methacrylates isn't a single exposure, it's repeated skin contact over time. Protect yourself and your clients by keeping product off skin and curing fully.
• 'HEMA-free' doesn't mean 'allergen-free.' Always check the full ingredient list, not just the marketing claim. Planet Nails offers both HEMA-containing and HEMA-free options — the SDS for every product is available to download directly from our website.
• Cheap products often cut corners on ingredients. Professional formulations from regulated markets are tested and balanced. Bargain products from unregulated sources can contain substituted or unlisted ingredients.
• Your SDS is your best friend. Every product you use professionally should have one. If a supplier can't provide one, that's a red flag.

You can download Planet Nails SDS documents any time from planetnails.com.au — just click the SDS tab in the top menu. And if you want to understand how to actually read an SDS, check out our companion blog: Un