Have you ever booked a Shellac manicure, wondered whether BIAB is different from builder gel, or heard someone mention Bio-Gel, rubber base or Acrygel — and thought, aren’t they all just gel?
You are not alone.
The nail industry has developed rapidly over the past few decades. New formulas, techniques and brands have introduced new possibilities, but they have also created a lot of confusing terminology.
One reason is that some names originally referred to specific brands or products, but are now commonly used to describe a whole category of nail treatments. At the same time, similar-sounding products can have very different properties.
Let’s look at how these names came about, what they generally mean and how modern nail products have evolved.
1. A Short History: From Acrylic to Modern Gel
The beginning of modern nails
One well-known story in nail history begins in 1957, when dentist Dr. Frederick Slack injured his thumbnail while working in a dental laboratory. He used dental acrylic and aluminium foil to create a temporary replacement, helping inspire the development of nail forms and artificial nail technology. The story is documented in the history of NSI, a professional nail product company.
Acrylic technology eventually became an important part of the nail industry. Traditional acrylic nail systems generally use a liquid monomer and polymer powder, which react and harden after they are combined. This allows nail technicians to create strong overlays and extensions without curing the material under a UV or LED lamp.
Acrylics opened up new possibilities for shaping and extending nails, but the industry did not stop there.
The development of UV-cured gel
UV-cured gel systems introduced another way to build and reinforce nails. Instead of hardening through the same liquid-and-powder reaction as traditional acrylic, these gels cure when exposed to a suitable light.
This technology gave nail professionals more options for consistency, application, shaping and finish. Different gel systems were developed for different purposes, from natural-nail overlays to longer extensions.
Today, “gel” is not just one product. It is a broad category containing many formulas with different levels of flexibility, strength, thickness and removal requirements.
The arrival of Shellac
In May 2010, CND launched CND SHELLAC, a specific nail-colour system developed over several years. It helped popularise the idea of a long-wearing, glossy manicure that combined aspects of traditional nail polish and gel technology.
The important distinction is that CND SHELLAC is a particular brand and product system, not the official name for every gel polish.
However, many people now use the word “Shellac” when they mean almost any gel-colour manicure. This is a good example of how everyday language can move beyond a product’s original name.
2. Why Does Everyone Say “Shellac”?
Imagine walking into a salon and asking for Shellac. You might simply mean that you want your nails painted with a glossy colour that lasts longer than ordinary polish.
The salon may understand exactly what you mean, even if it uses a different gel-polish brand.
This happens with many well-known product names. A brand becomes so recognisable that people start using its name as shorthand for similar products. (Like Kleenex or ChapStick)
In everyday language, people sometimes call this a genericised brand name. In trademark law, however, whether a name has legally become generic depends on the applicable law and the circumstances. A name becoming popular in casual conversation does not automatically mean that its trademark protection has disappeared.
For example, CND SHELLAC is a registered trademark in Ireland. We should distinguish between using a brand name to identify the original product and using it as a generic description for another product.
3. BIAB: Is It a Brand or a Type of Gel?
BIAB stands for Builder In A Bottle. The term is strongly associated with The GelBottle Inc., which helped make BIAB a widely recognised name in the nail industry.
Today, many customers and salons use “BIAB” more broadly when referring to builder gel used to reinforce natural nails.
But builder gel existed as a product category before the term became so popular. The key idea is not the name itself; it is the purpose of the product.
What does builder gel actually do?
Builder gels are designed to create a supportive layer over the natural nail. Depending on the formula, they can help add strength, build structure and refine the nail’s shape.
Some builder gels are thicker and firmer, while others are more flexible. Some are supplied in bottles, and others come in pots. Some can be soaked off using the product’s prescribed removal method, while others need to be filed off.
So the term alone does not tell you everything about the formula, its flexibility, its removal method or whether it is suitable for your nails.
4. What About Bio-Gel and Bio Sculpture?
This is another area where the terminology can become confusing.
Bio Sculpture Gel is the name of a professional nail product brand founded in South Africa. Its first clear gel product was registered in 1988 and was developed as a soak-off gel system for natural nails.
However, “bio gel” or “Bio-Gel” is also used by some salons and customers as a general description for a type of healthier nail gel, often one associated with natural-looking nails or nail reinforcement.
These uses are not necessarily referring to the same product.
The word “bio” on its own does not establish that a product is natural, non-toxic, allergy-free or healthier than another gel. For people, it might simply mean that they want TPO-HEMA free product or rubber base.
What is a rubber base?
Rubber base is another term commonly used for a flexible gel base coat. Depending on the formula, it can provide a degree of reinforcement while remaining more flexible than some traditional builder gels.
It is often chosen for natural nails that benefit from a thinner, more adaptable coating. However, flexibility and thickness vary between products, so “rubber base” does not describe one universal formula.
Some people may use terms such as Bio-Gel, rubber base and flexible builder gel in similar ways. Others use them to describe distinct products.
The most helpful question is not simply “What is it called?” but “What does this particular product do?”
5. HEMA-Free and TPO-Free: What Do These Labels Mean?
As nail products have developed, more attention has been given to ingredients, correct application and potential allergic reactions.
Two terms you may increasingly see are HEMA-free and TPO-free.
What is HEMA?
HEMA stands for 2-hydroxyethyl methacrylate. It is an ingredient used in some gel and nail enhancement products.
HEMA can cause allergic contact dermatitis, particularly when uncured product comes into contact with the skin. This is one reason careful application matters: gel should not be allowed to cure on the skin, and products should be used according to their instructions.
In the EU, HEMA and Di-HEMA TMHDC in nail products are restricted to professional use and require a warning about the possibility of an allergic reaction.
A HEMA-free label means the product is formulated without HEMA. It does not mean that the product contains no other ingredients capable of causing an allergy. Other acrylates and methacrylates can also cause sensitisation.
What is TPO?
TPO stands for Trimethylbenzoyl Diphenylphosphine Oxide. It was used in some light-cured cosmetic products as a photoinitiator, helping the product harden under light.
The EU prohibited TPO in cosmetic products from 1 September 2025 following its classification as a substance toxic to reproduction. The prohibition also applies to professional salon use in the EU.
A TPO-free label means that TPO is not included in the product formulation. It is important to distinguish this specific ingredient claim from a general claim that a product is completely safe or risk-free.
Does HEMA-free and TPO-free mean allergy-proof?
No. These labels tell you something specific about a product’s ingredients, but they do not guarantee that nobody will react to it.
Good product selection, proper curing with compatible equipment, avoiding skin contact and following professional instructions all remain important.
At our salon, the BIAB and rubber base products we use are HEMA-free and TPO-free. We believe customers should be able to understand what these labels mean without assuming that any one ingredient label tells the whole story.
6. Hard Gel vs. Acrylic: What Is the Difference?
Acrylic and hard gel are both used to build strong nail overlays and extensions, but they work differently.
| Feature | Traditional acrylic | Hard gel |
|---|---|---|
| How it hardens | Through a chemical reaction after liquid and powder are combined | Through curing under a compatible UV or LED lamp |
| Typical application | Liquid monomer and polymer powder | A gel applied and shaped before curing |
| Odour | Often has a noticeable monomer smell | Often lower odour, although this depends on the product |
| Strength and structure | Can create strong overlays and extensions | Can create strong overlays and extensions |
| Removal | Usually filed down or removed according to the system | Generally filed off; traditional hard gel is not soak-off |
| Best choice | Depends on the desired result and the technician’s system | Depends on the desired result and the technician’s system |
Neither system is automatically better for every person. The right choice depends on nail length, desired shape, product properties and the technician’s skill.
It is also worth remembering that nail damage is not determined by the product name alone. Aggressive filing, picking or peeling product off, and incorrect removal can damage the natural nail. Careful application and maintenance matter with both systems.
7. Acrygel: A Newer Hybrid Approach
Acrygel, also called polygel by some brands, is a product category that combines characteristics associated with acrylic and gel systems.
It is generally supplied as a thicker, workable material that the technician shapes before curing it under a suitable lamp. This can offer greater control during application while allowing the technician to build a strong structure.
One reason people like these products is that they can have less noticeable odour than traditional liquid-and-powder acrylic systems. They can still provide substantial strength when correctly applied.
However, formulas vary, and “acrygel” does not guarantee a particular level of flexibility, strength, odour or ease of removal. The manufacturer’s instructions still matter.
It is best understood as another option in the nail technician’s toolkit, rather than a product that automatically replaces every other system.
8. Why Do Nail Products Keep Changing?
The nail industry continues to evolve because customers want different things.
Some want long extensions and dramatic shapes. Others prefer short, natural-looking nails that feel comfortable at work. Some want a flexible coating, while others need a stronger structure. Many people simply want a glossy colour that lasts.
Manufacturers respond by developing different formulas, application methods and removal systems.
Modern professional nail products can offer more choice than ever before, including:
Different levels of strength: from flexible base coats to firmer builder gels and extension systems.
More application options: including bottles, pots, liquid-and-powder systems and hybrid-style products.
Different finishes: from clear, natural-looking overlays to highly pigmented colours and intricate nail art.
Ingredient-conscious formulations: including products made without selected ingredients such as HEMA or TPO.
More specialised systems: designed for particular nail lengths, shapes, application techniques or maintenance routines.
Innovation does not mean that every new product is automatically better. A newer formula still needs to be evaluated according to its ingredients, performance, correct curing requirements, removal method and suitability for the individual client.
The real progress is having more options, and being able to choose between them with better information.
9. How Can You Choose the Right Nail Treatment?
You do not need to memorise every brand or technical term before booking a manicure. A few practical questions can help:
If you want colour only: Ask about a gel-polish system.
If you want extra support for natural nails: Ask whether a flexible base or a builder gel is more suitable for your nail type and lifestyle.
If you want very long nails or extensions: Ask about hard gel, acrylic or an appropriate hybrid system, and how the product will be maintained.
If you have experienced a reaction to nail products before: Tell the salon before treatment. Avoid applying more product to affected skin, and seek appropriate medical advice if you suspect an allergy.
The product name is only one part of the decision. Your natural nails, the desired result, the technician’s technique and the care taken during removal all matter.
Final Thoughts: Look Beyond the Name
Shellac, BIAB, Bio-Gel, rubber base, hard gel, acrylic and Acrygel may sound like a confusing collection of terms. But once you understand the difference between a brand name, a product category and a product’s actual properties, the industry becomes easier to navigate.
Some names become popular shorthand. Others describe a specific system. And products that sound similar may still behave quite differently.
The best approach is to ask questions, understand what is being applied to your nails and choose a professional who can explain the product and its maintenance clearly.
Because beautiful nails are not just about the name on the bottle, they are about choosing the right system and using it properly.
