Being right-handed, my nails on that side naturally go through more, and it's always the side that lets me down. One nail will break, and then I have to cut them all off and go short *sigh*. Recently, I outdid myself, racking up three broken nails and being left with a hand of completely different nail lengths. So, I decided it was finally time to try BIAB (aka, Builder in a Bottle).
You've probably heard talk of BIAB, given how steadily it has grown in popularity over the last few years. But like me, you may not have got around to trying it yet.
What is BIAB nails?
Speaking to professional nail artist Giorgia Cappella, we learned that BIAB combines the strength of builder gels with the convenience of a bottle application. "BIAB is used for strengthening natural nails, creating overlays, or even sculpting extensions," Giorgia says.
Created by The GelBottle, BIAB is harder than a regular gel polish, but kinder to the nail than acrylics. Plus, The GelBottle made sure it can be soaked off. A strength barrier for natural nails, it can also fill cracks and ridges, give the nail shape, and be used to sculpt and form extensions.
Key features of BIAB:
- Strengthens natural nails: Helps weak nails grow without breaking.
- Self-levelling formula: Makes application smoother and easier.
- Soak-off removal: Unlike traditional hard gel or acrylics, BIAB can be soaked off with acetone.
- No need for a base coat: It can be applied directly to the natural nail.
- Comes in over 70 shades – more recently we’ve introduced darker tones, but best known for sheers, nudes and light pinks: Ideal for a natural, clean look or as a base for putting nail art and gel on top.
Is BIAB good for your nails?
BIAB promotes healthy nails through a combination of ingredients that provide strength, flexibility, moisture regulation, and durability. Giorgia breaks them down, below:
- Dipentaerythritol hexaacrylate ensures strong adhesion, preventing breakage.
- Hydroxypropyl methacrylate (HPMA) maintains nail integrity and flexibility.
- HEMA (hydroxyethyl methacrylate) regulates moisture, preventing brittleness.
- Isobornyl acrylate enhances durability, protecting against wear and tear.
- Trimethylbenzoyl diphenylphosphine oxide ensures thorough curing for long-lasting wear.
- Acrylic acid aids in adhesion, preventing lifting and peeling.
- Bis (methacryloyloxyethyl) phosphate balances strength and suppleness.
- Polyethylene terephthalate (PET) and polyurethane-17 may provide additional strengthening properties.
Giorgia says that "By harnessing the synergistic effects of these ingredients, BIAB not only beautifies the nails but also fortifies them from within.
"With regular application, it promotes nail health by providing strength, flexibility, moisture regulation, and durability, resulting in nails that are not only stunning but also resilient and healthy."
It seemed to tick all the boxes, so I went to Duck & File in Islington, where resident nail tech Precious said she could make my broken nail hand look just like my perfect one – and I was very, very, up for that.
How is BIAB applied?
After filing and buffing my dodgy talons, my nail tech attached fun little splints called 'forms' to the fingers that needed extensions. All nails had a slip coat of BIAB (similar to a base coat principle), which was cured in the lamp before she began building the nails.
On the ones with forms, this meant dragging a 'bead' (read: dollop) of BIAB up from the cuticle, building over the form and shaping it for the extension. The other nails were also built up, but this was more about creating an apex and shape, as the length was already there. Each has to be individually cured in the lamp right after building to minimise running.
After all nails were cured, Precious removed the forms and warned me the extensions might look a little 'ugly' at this point, as they were roughly moulded. But after clipping, filing and smoothing, they looked exactly like my natural nails.
I chose a clear BIAB shade, though it is available in a range of pinks and nudes. If you go for clear, you can get a gel mani over the top, meaning way more colour options.
Honestly, once they were painted, the difference blew me away. Precious really had transformed my right hand to look exactly like my left; it was completely imperceptible. We then spent a considerable amount of time trying to get pics, but I am the worst hand model, my hands turn into weird claws from your nightmares, so I'd say watch the TikTok for their real glory:
How long do BIAB nails last?
"When applied correctly, BIAB mimics the natural apex of the nail, providing reinforcement at the nail’s stress point to reduce the risk of premature breakages," Giorgia tells us.
"As each person's nails grow at different rates, the position of the stress point naturally shifts over time. To maintain optimal strength and structure, we recommend BIAB maintenance appointments every 2– 4 weeks, depending on individual nail growth. These appointments allow the apex to be repositioned to suit the new length of the nail."
In short, BIAB is highly durable and will remain bonded to the nail, but regular maintenance is essential to ensure long-lasting results and prevent damage. It all depends on how fast your nails grow!
How to make your BIAB manicure last longer
As Giorgia has reinforced, aftercare is essential. “Regularly applying cuticle oil and hand cream helps to hydrate the skin and stimulate healthy cell renewal, keeping both your skin and nails nourished and your manicure looking fresh between appointments,” says Cappella. “To protect your nails, avoid direct contact with harsh chemicals by wearing gloves during cleaning or household tasks. Chemicals can dry out the skin and dehydrate the nail, compromising the longevity of your BIAB.”
Can you get BIAB nails infilled?
One of the things that makes BIAB healthier for your nails is that it can be infilled. So, two weeks later, I was back to see what that process was like. The gel polish had to be removed with an e-file to get to the BIAB, a step that can be avoided if you use a colour BIAB. Then, Precious cleaned up my cuticles and any lifting BIAB, ready to have new BIAB applied over the top. She particularly concentrated on levelling out the area of growth at the cuticle. It was much more similar to the first application than I'd expected. The biggest difference was that it didn't require the forms.
I chose to round off my square nails, and the original extensions were shaped in the exact same way, as if they were my own. It wasn't until we finished that I realised only two of my nails still had a little bit of extension left on the tip. I couldn't believe that in another two weeks, my broken nails would have been completely evened out, without having to go short.
How to remove BIAB at home
As mentioned above, BIAB should always be removed with an electric nail file by a professional. However, if you do not have access to a salon and need to take off your mani at home, we recommend soaking your tips in acetone and gently filing them down. The removal process is the same as removing acrylics, which you can read more about here.
How much does a BIAB manicure cost?
It varies from salon to salon. At Duck & File, the service costs around £55 for BIAB with extensions (nail-dependent), and an extra £3 charge for gel colour if you go for clear. I can't believe the long-awaited answer to a broken nail is really no more expensive than luxe gel manicures.
Do we recommend BIAB?
I'm very attached to my nail salon with their half-hour gel manis (including removal, wild I know), so I don't know if BIAB will tempt me full-time. However, if you are looking to strengthen and grow your nails, this is the best option for you!
So, the next time I break a nail, I will be going straight for another round of BIAB rehab to coach it back to health with its brothers and sisters.
Meet the expert
Giorgia Cappella is the Head of Education and Spa and a regular Cosmopolitan Contributing Expert. After training in nails in 2018, she quickly found her passion and, within a short amount of time, joined TGB as a Brand Ambassador for the UK. Giorgia hosts all of The Gel Bottle training courses and is incredibly skilled in all things BIAB and nail art.
Elena Chabo is Cosmopolitan UK's former beauty writer, working on everything from buzzy celeb news and trending beauty, to sincere first-person reviews and engaging video content for social media. She also creates meatier features and expert-led how-to guides, for print and online. Her passion for Black beauty, textured hair, and the ways beauty interacts with culture, society, identity and relationships, quickly took over her writing career and led her into beauty journalism. Following an MA in Magazine Journalism in 2017, she cut her teeth across various roles at Stylist Magazine, before taking on a Digital Writer role at Good Housekeeping. It was here that beauty took centre stage and she launched and ran the site's first stand-alone beauty section. Remaining at Hearst, she joined the Cosmo beauty team in 2022. Find her on LinkedIn.
Lia Mappoura (she/her) is the Beauty Writer at Cosmopolitan UK, with over four years of experience reporting across the brand's print, social, video and digital platforms. Lia covers everything from emerging trend analysis to viral celebrity hair and makeup moments, making her an expert at spotting the season’s next big beauty look (before it takes over social media feeds).
In 2025, she was named The Rising Media Star at the Love Perfume Awards with The Perfume Shop, recognised for her outstanding digital fragrance content and for building genuine authority within the space. She is passionate about challenging outdated beauty stereotypes, championing inclusive representation in beauty, and educating readers on the trends, products and conversations shaping the industry today. Follow her on Instagram or find her on LinkedIn.
