Builder gel promises to help you grow and strengthen your natural nails with a 'coat of armour'. Here's exactly how BIAB nails differ from a gel mani and acrylic extensions and how to do them at home

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There are many salon tricks to making your mani last longer — choosing neutral colours rather than brights so that your new nail growth doesn't show or opting for 'negative space' nail art designs which make a virtue of displaying entire sections of natural nails.

But now there's a new technique: BIAB nails or 'builder gel' nails. The new salon treatment - which, like gel nails has also spawned at-home options - not only makes your gel mani last at least twice as long without chipping. It also lets you 'infill' your regrowth. What's more, it's helping gel fans grow their nails longer and stronger so they can leave more time between appointments. Like Polyfilla for nails, it can even fill in chips and tears. Described as a "chic coat of armour for your nails", BIAB, which stands for Builder In A Bottle is rapidly also winning over fans of acrylic nails, who are choosing it as a less damaging but still long-lasting option. 

What are BIAB nails?

With BIAB (pronounced by-abb), the 'builder' gel in question is a clear or pastel-toned gel that is applied to bare nails either alone or as the base coat for your regular gel colour. It provides a visibly thicker and stronger base coat for the nail than a conventional base gel, which is why it lasts longer. It provides armour for nails which are prone to bending, snapping and chipping, allowing them to grow longer. 

Like a gel mani, it's cured under a UV lamp and comes off in the same way, via filing and soaking with acetone. It's gone viral on TikTok with hashtag #biab reaching over 128 million views.

BIAB was created by gel nail polish brand The Gel Bottle, whose founder Daisy Kalnina wanted a solution for her clients whose nails were chipping or tearing between gel appointments. They wanted something long-lasting without having to opt for acrylic nails, which require glue to apply and at least an hour in the chair, and an e-file drill to remove.  She created the 'builder' gel as a protective layer and strengthening barrier, one that could be applied in the same appointment as a regular gel mani. 

"When cured under a UV lamp, it provides a finish that's harder than regular gel polish, but less disruptive to the nail than acrylic extensions. This helps to protect nails and support natural nail growth, like a chic coat of armour for your nails," explains Helena Marimon, TGB senior nail expert. "The BIAB formula is completely different to regular gel (it's also got a visibly thicker consistency) so think of it as an upgrade that enhances longevity and strength."

On Tiktok, the latest thing is to share your BIAB nail growth journey over the course of weeks and months, from tiny, stubby, bitten-down nails to full, length Hailey Bieber-worthy talons; #biabjourney has racked up over 23 million views. It's deeply satisfying to watch. 

Celebrity manicurists like Alexandra Teleki @thehotblend are on board with the trend too (she uses the nudey shade BIAB19 in every treatment either as a base or alone), and salons such as Townhouse, Soho House, Dryby London and Shoreditch Nails all offer the treatment. 

Who would benefit from BIAB nails?

Builder gel is perfect for nail biters or pickers who want to grow their nails longer. With a thicker base, there's less opportunity or temptation to pick or bite, points out Rani Narayan, senior nail art specialist at Shoreditch Nails. If you are someone who forgets about their polish and tends to chip it, the strong 'builder' coat can provide that extra protection. Or if, like me, you have naturally, weak, brittle or bendy nails, that feel impossible to grow, you might be able to achieve those vital extra millimetres with BIAB.

To try it, I went to Shoreditch Nails, which has been offering the service for the past eight months and is seeing it steadily grow in popularity among clients. “Once you start using builder gel, you won’t go back,” says Rani (who has the prettiest, most perfect glazed donut nails I’ve seen). Why? Well, they’ll last longer for a start. 

How long do BIAB nails last compared to a regular gel mani?

A gel mani typically lasts ten days to two weeks before peeling or chipping. Now BIAB make can make that same gel mani last around three weeks, according to Rani. 

With a regular 'infill' treatment (see below) it can even last for months, says Helena, so long as you also practise proper hand and nail care.

What's the difference between BIAB nails and acrylics?

"BIAB has allowed our clients to grow out and maintain healthy, natural nails to achieve a look you’d otherwise need extensions or acrylic to create," says Rani. But unlike acrylics, they don’t require any powder or glue, or the use of an electric drill to remove them, which is why they are being touted as a less harsh alternative.  

Like acrylics, builder gel can also be used to create short nail extensions.

How can BIAB reshape your nails and fix broken nails?

The revolutionary thing about BIAB is that, in the same way that a dentist uses composite bonding to build up and even out your teeth, it can even out or reshape nails where length might have been lost from biting. So you don’t have to worry about having one or two short nails or waiting for them to grow.

"As the name suggests, you can sculpt and build tip extensions with the product," explains Rani. Equally, the thicker gel formula allows you to fix small breaks in nails. 

What are BIAB infills?

Another way that BIAB helps you grow your nails is that you don't have to have the whole of your colour removed, and your nails filed and shaped at each appointment. BIAB nails can also be 'infilled' by simply filling in the natural nail regrowth at the base of the nail bed. This is made possible because the rest of your nail colour is still in good condition and doesn't need to be re-done. 

There are hundreds of videos on TikTok of people having their builder gel nails infilled. Not all salons offer BIAB infills, though, for example at Shoreditch Nails, technicians recommend a full soak-off with acetone with each treatment. 

How much do BIAB nails cost and how long do they take?

Most salons and technicians add the cost of builder gel onto a regular mani. For example, at Shoreditch Nails the BIAB is offered for an extra £10 on top of a gel mani (from £39) and an extra 30 minutes is added to your appointment for the sculpting and curing process.

We tried BIAB builder gel nails in-salon

As someone who has never been able to naturally grow out my nails, I was excited to discover of a product that can double if not triple the lasting power of a regular gel mani and help me grow my nails,  for an extra £10. The full-works gel mani with builder gel at Shoreditch Nails cost £49.

I went for a nude base which matches my exact natural nail and an acid green and pink combination as I was going to a festival. After a file and shape, Rani applied the BIAB gel which is thicker in consistency and I was initially a little worried that it would bulk out my nails (though I'm pleased to report once it didn't). A week later, I'm impressed with how immaculate they still look, particularly after a weekend pitching a tent and not sparing a thought for my mani over my camping break. 

The appointment did take slightly longer though (about one hour 15 in total with French tip designs) so you will have to factor that in.
Next time I'll be opting for one of the more popular nude shades, which will probably better disguise regrowth for my elongated mani. 

Can I do BIAB nails at home?

Like all things beauty, what starts in the salons and professional spaces eventually trickles down to the DIY market. BIAB nails are no exception and have happened rather quickly. You can now do your own builder nails at home thanks to the new Mylee 5-in-1 Builder Gel, £13. It comes in four neutral shades: clear, white, light pink, and peach. The clear shade can be used as a base colour for other gel polishes to go on top of while the coloured versions should be applied on top of a separate base coat. 

Similar to the professional version, they contain strengthening ingredients to help nails become less brittle and grow longer. You apply a coat of the gel, and then – here’s the slight rub – you then need to cure it under a LED or UV lamp, which requires an extra investment, Mylee Pro LED Curing Lamp, £50. Once that’s cured, which takes about 60 seconds, you apply another two coats, curing each layer, and then apply a top coat which also needs curing. And then you're done.  Mylee says you can also use the Builder Gel as a top coat for extra strength and shine. 

You can create builder tips or extensions using special molds or cones or 'nail forms' and a paste-like polygel which comes in paintable clear or nude shades  (Mylee Magic Extender Gel, £15)  however we found this rather fiddly and that it lasted two to three days. It requires dedication and skill to master. However, we found the paint-on Builder Gel a great replacement at-home gel base coat. It builds stronger nails and made our home gel mani last two weeks instead of one. 

How to remove builder nails at home

Just like your professionally applied BIAB nails, taking home-painted builder nails off at home requires the same steps.  Try the Mylee Get Soaked Gel Polish Remover Kit £24.

  • Begin by filing the surface of the nail - this will take the shine off the top coat leaving your nails look slightly scuffed and matte. This allows the remover to sink in.
  • Place a cotton pad soaked in acetone or gel remover over the nail - some people like to wrap it in foil so it doesn’t move.
  • Remove the pads after ten to 15 minutes and you should be able to gently push away any remaining gel with a cuticle stick.
  • Treat your nails to some cuticle oil to give your nails some extra hydration.