NEW

1 9

STRENGTH — Strengthening Nail Serum

Strengthens Brittle Nails
Use After Gel Polish

$13.99

A 7-day layering serum for nails that feel weak, brittle, or worn down from constant gel cycles. Instead of one coat, it builds up over a week, working with keratin, the protein your nails are made of, to help improve resilience and strengthen nails over time.

Layered process. Applied in stages across a 7-day nail treatment cycle for a more thorough result than a single coat.
Keratin protein. Formulated with amino acids that support your nails' own structure to help build strength.
Use between manicures. Use this strengthening serum on bare nails to condition and strengthen before your next manicure.

Made in USA • Vegan • Cruelty-Free

95% noticed improved nail quality.

Get the full routine and save

Nail Ritual BundleStrengthen and enhance your natural nails with SUNUV’s three treatments

Free US Shipping $50+
60-Day Returns

STRENGTH — Strengthening Nail Serum

$13.99

TikTokで購入

3-in-1

Color That Cares

One coat is a brightening, sheer nude that adapts to your natural nail tone. Light-reflecting pigments work with the nail surface, not over it, softening discoloration and unevenness into a luminous, even finish. Build to two coats for a more defined glow.

GLOW is built to flex: base coat, sheer nude, or twice-weekly treatment ritual. Used consistently, the effects are cumulative.

The active is Phaeodactylum Tricornutum Extract, a marine algae extract that interacts with light across the nail's surface, producing an adaptive finish rather than a single flat shade. In a 3-week panel test, 95% saw improved nail quality, 89% saw stronger, less fragile nails, and 89% saw healthier nails.

3 Ways to Wear

Base Coat, nude color or nail treatment

Made in USA

Our treatments are formulated domestically

95% Improvement

3-week user test: 95% improved nail quality

Vegan & Cruelty Free

Cruelty Free International eligible

Compare our nail treatments

Which solution is right for your nails?

GLOW, NOURISH, and STRENGTH aren't three coats meant to go on at once. They're three answers to three different nail concerns, used whichever way your nails need that week.

GLOWNail Color Corrector

$13.99

NOURISHHydrating Cuticle Oil

$13.99

STRENGTHStrengthening Serum

$13.99

Addresses

Tone & finish

Hydration

Resilience

Format

Sheer tinted liquid

Biphasic oil and serum

Layering serum

Worn

Under polish, alone, or as a bare-nail treatment

Under polish or on bare nails

Bare nails only. Used as a 7-day treatment cycle.

Usage

As needed, any time cuticles feel dry

7-day cycle used every other day. Repeated for 2–3 weeks.

Whichever treatment matches what your nails need that week.

Panel Results

95% saw improved nail quality.
89% saw stronger nails.
89% saw healthier nails.

Contains Buckwheat Extract: independently
shown in laboratory testing to reduce nail
keratin damage by 51% under stress.

93% saw stronger nails at 2 weeks.
100% saw less fragile nails at 3 weeks.

Best for

Tone correction or a natural finish.

Dry, cracking cuticles.

Weak, brittle or thin nails

Questions, sorted

Everything
before your first cure.FAQs

The questions our customer team actually gets — answered plainly, no manual-speak.

Contact our team

STRENGTH is a layering serum for nails that feel weak, brittle or worn down from constant gel cycles. Instead of a single coat, it builds up over a 7-day cycle. Its amino acid and plant protein complex supports keratin, the protein your nails are made of, to help improve resilience and strengthen nails over time.

STRENGTH works on the structure of the nail plate. Nails are built from layers of keratin, and gel removal, water exposure and daily wear can leave them thin, soft and prone to breaking. Each coat deposits an amino acid and plant protein complex onto the nail surface, and each layer bonds to the last, so the reinforcement builds over the cycle.

A strengthening serum helps weak, brittle nails become more resilient between manicures. In user testing, 93% of participants reported stronger nails after two weeks of STRENGTH, and 100% reported less fragile nails after three weeks.

Most users notice a difference within two weeks. In user testing, 93% reported stronger nails after two weeks and 100% reported less fragile nails after three weeks. For best results, repeat the 7-day cycle for 2–3 weeks.

Apply STRENGTH three times over a 7-day cycle: on day 1, day 3 and day 5, layering each coat over the last. Remove it on day 7 and repeat the cycle for 2–3 weeks for best results.

No. Don't remove STRENGTH between applications. Each new coat goes directly over the previous one, and that build-up is what delivers the strengthening effect. Remove it only on day 7.

On day 7, use acetone to break down and lift the layered formula completely. Never peel or pick the serum off, because that removes layers of the natural nail with it. Acetone is drying, so apply NOURISH – Hydrating Cuticle Oil right after removal.

STRENGTH is designed for bare nails between gel manicures, when your nails need to recover. Complete the cycle, remove it, rest your nails, then go back to gel. Don't apply gel over STRENGTH.

No. STRENGTH is an air-dry serum, so there's nothing to cure.

Use STRENGTH to reinforce weak nails over its 7-day cycle, and NOURISH right after each removal to rehydrate nails and cuticles. Between cycles, GLOW evens out nail tone for a natural, polished look.

STRENGTH — Strengthening Nail Serum