The Welpr Rating is determined by a scoring formula. The formula takes into account the products safety, user satisfaction, and eco-ethical standing. Click here to learn more.
Best Non-Toxic Nail Hardener in 2025
Updated:
Aug 28, 2025
Written by Camille May
Cofounder & Product Curator
+ 1 more
Medically reviewed by Olushola Awoyemi
PhD Environmental Toxicology
As an Amazon Associate, we earn from qualifying purchases. Our use of affiliate links does not influence how we rate products. Learn more about our affiliate policy here.
What we look for:
- Free from formaldehyde, toluene, DBP, benzophenones, and other high-risk toxins
- No synthetic fragrance, unapproved dyes, or undisclosed ingredients
- “X-free” claims (like 10-free or 21-free) verified against the full ingredient list
- Third-party certifications when available
- Full transparency with every ingredient clearly listed
Find Non-Toxic Nail Hardener
No items found.
Nail Lacquer with Hardeners - China Glaze
Welpr Rating
4.95
/5
Certifications
Third-party certifications are key indicators of a product's safety, ethics, and environmental impact. Click the icon to verify the certification.
Highlights
Highlights aren't always verifiable, so you're trusting the brand when they say "lead free", etc. If the highlight icon is "clickable", it means we've verified the highlight.
User Satisfaction
User satisfaction is calculated using online reviews and a Bayesian average across all personal care and cosmetic products on Welpr.
Est. Price
$6.49
Product Details
- Long-wearing and flexible, ensuring your nails look great without chipping.
- Non-thickening formula eliminates the need for additional thinners.
- Free from DBP, toluene, and added formaldehyde, making it a safer choice for health-conscious users.
- Ideal for special occasions like weddings and proms, as well as adding a classy touch to French manicures.
Pros & Cons
Pros
- Offers a stunning iridescent and holographic finish, perfect for a unique manicure.
- Quick-drying formula helps prevent smudges and allows for a speedy manicure.
- Highly praised for its long-lasting wear, keeping nails looking fresh for days.
- Sheer and versatile color options that are ideal for layering or creating subtle looks.
- Recommended by longtime users for its reliable quality and vibrant, lasting color range.
Cons
- Some users may find the polish too thin and needing multiple coats for full coverage.
- A few experienced unexpected color changes, which could be a surprise for those seeking specific shades.
Ingredients
Ingredients can vary by product variation and may change at any time by the manufacturer. For the most complete and up-to-date list of ingredients, refer to the product packaging.
To analyze individual ingredients, use INCIDecoder.
Ingredients: Butyl Acetate, Ethyl Acetate, Nitrocellulose, Adipic Acid/Neopentyl Glycol/Trimellitic Anhydride Copolymer, Dipropylene Glycol Dibenzoate, Isopropyl Alcohol, Stearalkonium Bentonite Acrylates Copolymer, Iron Oxides (C177499), Ferric Ferrocyanide (C177510), Titanium Dioxide (C177891)
Hardener with Keratin, Calcium and Garlic - Steel Nails
Welpr Rating
4.85
/5
Certifications
Third-party certifications are key indicators of a product's safety, ethics, and environmental impact. Click the icon to verify the certification.
Highlights
Highlights aren't always verifiable, so you're trusting the brand when they say "lead free", etc. If the highlight icon is "clickable", it means we've verified the highlight.
User Satisfaction
User satisfaction is calculated using online reviews and a Bayesian average across all personal care and cosmetic products on Welpr.
Est. Price
$8.16
Product Details
- Enhances nail growth and prevents chipping and breakage.
- Protects nails from becoming brittle and weak.
- Contains garlic to help harden and shape nails.
- Calcium contributes to maintaining nail strength.
- Works effectively as a base or top coat for ongoing nail improvement.
Pros & Cons
Pros
- Effectively strengthens nails, making them less prone to breakage.
- Quick-drying formula that's easy to apply.
- Serves as a good base and top coat, protecting and enhancing the shine of your polish.
- Can improve nail health and growth for those with previously weak or damaged nails.
Cons
- Some users with sensitive nails report a burning sensation upon application, suggesting it may not be ideal for all.
- Overapplication could lead to peeling, especially if more than two thin coats are applied.
Ingredients
Ingredients can vary by product variation and may change at any time by the manufacturer. For the most complete and up-to-date list of ingredients, refer to the product packaging.
To analyze individual ingredients, use INCIDecoder.
Ingredients: Allium Sativum Bulb Extract, Keratin, Calcium Pantothenate, Nitrocellulose, Butyl Acetate, Ethyl Acetate, Polyester-23, Adipic Acid, Butyl Acrylate/Styrene Copolymer, Pentaerythrityl Tetraisostearate, Sodium Hyaluronate
Nail Hardener - Londontown
Welpr Rating
4.85
/5
Certifications
Third-party certifications are key indicators of a product's safety, ethics, and environmental impact. Click the icon to verify the certification.
Highlights
Highlights aren't always verifiable, so you're trusting the brand when they say "lead free", etc. If the highlight icon is "clickable", it means we've verified the highlight.
User Satisfaction
User satisfaction is calculated using online reviews and a Bayesian average across all personal care and cosmetic products on Welpr.
Est. Price
$20.00
Product Details
- Designed for all skill levels, from beginners to seasoned nail artists.
- Includes tools like dotting nail design pen with brush, crystal glass double-sided nail file, and pedicure jelly toe separator.
- Features manicure nail art decals and a clean-up cuticles set.
- Offers multiple design options such as Lavender, Black, White, Glitter Cosmic, and Petals in Bloom.
- Easy to use and portable, facilitating salon-worthy nail art at home.
Pros & Cons
Pros
- Effectively strengthens and hardens nails, promoting growth.
- Users report long-lasting results with natural nail improvement.
- Can be used alone or as a base coat for added flexibility.
- Fast-drying formula is convenient for busy schedules.
- Many users see a noticeable change in nail health within a week.
Cons
- Some users with sensitive nails found it harsh, leading to peeling or softness.
- A few users reported the product getting thick and gloopy over time.
Ingredients
Ingredients can vary by product variation and may change at any time by the manufacturer. For the most complete and up-to-date list of ingredients, refer to the product packaging.
To analyze individual ingredients, use INCIDecoder.
Ingredients: Ethyl Acetate, Butyl Acetate, Alcohol Denat, Nitrocellulose, Acrylates/Hydroxyesters Acrylates Copolymer, Isopropyl Alcohol, Acetyl Tribuyl Citrate, Adipic Acid/ Neopenyl Glycol/ Trimellitic Anhydride Copolymer, Dipropylene Glycol Dibenzoate, Etocrylene, Brassica Campestris (Rapeseed) Seed Oil, Brassica Campestris Flower Extract, Chamomilla Recutita (Matricaria) Flowe Extract, Cucumis Sativus (Cucumber) Fruit Extract, Oenothera Biennis (Evening Primrose) Flower Extract, Carthamus Tinctorius (Safflower) Seed Oil, Tocopheryl Acetate (Vitamin E), Dimethicone, CI 42090, CI 60725
Nail Hardener - L.A. Colors
Welpr Rating
4.7
/5
Certifications
Third-party certifications are key indicators of a product's safety, ethics, and environmental impact. Click the icon to verify the certification.
Highlights aren't always verifiable, so you're trusting the brand when they say "lead free", etc. If the highlight icon is "clickable", it means we've verified the highlight.
User Satisfaction
User satisfaction is calculated using online reviews and a Bayesian average across all personal care and cosmetic products on Welpr.
Est. Price
$7.50
Product Details
- Promotes the growth of healthy, natural nails.
- Advanced formula hardens and strengthens nails.
- Prevents peeling, splitting, and breaking.
- Ideal for thin and weak nails.
Pros & Cons
Pros Mentioned
- Effective
Ingredients
Ingredients can vary by product variation and may change at any time by the manufacturer. For the most complete and up-to-date list of ingredients, refer to the product packaging.
To analyze individual ingredients, use INCIDecoder.
Ingredients: Ethyl Acetate, Butyl Acetate, Isopropyl Alcohol, Nitrocellulose, Phthalic Anhydride/Trimellitic Anhydride/Glycols Copolymer, Acetyl Tributyl Citrate, Adipic Acid/Fumaric Acid/Phthalic Acid/ Tricyclodecane Dimethanol Copolymer, Benzophenone-1, Violet 2 (Ci 60725), Ferric Ammonium Ferrocyanide (Ci 77510)
Nail Hardener Polish - Karma Organic
Welpr Rating
4.6
/5
Third-party certifications are key indicators of a product's safety, ethics, and environmental impact. Click the icon to verify the certification.
Highlights
Highlights aren't always verifiable, so you're trusting the brand when they say "lead free", etc. If the highlight icon is "clickable", it means we've verified the highlight.
User Satisfaction
User satisfaction is calculated using online reviews and a Bayesian average across all personal care and cosmetic products on Welpr.
Est. Price
$11.99
Product Details
- Reduces brittleness by reinforcing nail layers to prevent splitting and peeling.
- Enhances natural durability and helps nails grow stronger with each application.
- Uses 100% natural ingredients derived from pure, plant-based oils.
- Loaded with vitamins A, E, and C to support healthy nail growth and improve texture.
- Prevents breakage and repairs nails, restoring their natural strength.
Pros & Cons
Pros
- Free from harmful chemicals like toluene and formaldehyde.
- Dries quickly, within minutes, and sets with a glossy finish.
- Strengthens nails with vitamins A, E, and C, leading to healthier appearance.
- Dual-purpose as both a base and top coat, simplifying routine.
- Cruelty-free and supports healthier alternatives.
- Helps nails look well-maintained even when worn alone.
Cons
- Some users experienced peeling or chipping after a few days.
- A few found the initial strong smell off-putting.
Ingredients
Ingredients can vary by product variation and may change at any time by the manufacturer. For the most complete and up-to-date list of ingredients, refer to the product packaging.
To analyze individual ingredients, use INCIDecoder.
Ingredients: Butyl Acetate, Ethyl Acetate, Nitrocellulose, Adipic Acid/Neopentyl Glycol/Trimellitic Anhydride Copolymer, Acetyl Tributyl Citrate, Isopropyl Alcohol, Stearalkonium Bentonite, Acrylates Copolymer, Hydrogenated Castor Oil/ Sebacic Acid Copolymer, Styrene /Acrylates Copolymer, Benzophenone-1, Silica, Titanium Dioxide/Cl 77891, Persea, Gratissima (Avocado) Oil, Prunus Armeniaca (Apricot) Kernel Oil Trimethylpentanedivl Dibenzoate, Red Iron Oxide/Cl 77491, Water, Acetyl Methionine, Acetyl Cysteine
Powerful Acrylic Gel Strength Hardener - Sally Hansen
Welpr Rating
4.55
/5
Certifications
Third-party certifications are key indicators of a product's safety, ethics, and environmental impact. Click the icon to verify the certification.
Highlights
Highlights aren't always verifiable, so you're trusting the brand when they say "lead free", etc. If the highlight icon is "clickable", it means we've verified the highlight.
User Satisfaction
User satisfaction is calculated using online reviews and a Bayesian average across all personal care and cosmetic products on Welpr.
Est. Price
$9.49
Product Details
- Instantly strengthens fragile, soft, or damaged nails.
- Cures in just 60 seconds, leaving nails hard as wraps.
- Easily provides a clear, smooth, and shiny finish.
- Single-step application without mixing or mess.
Pros & Cons
Pros
- Helps strengthen and protect weak or splitting nails effectively.
- Long-lasting formula, stays on for up to two weeks without chipping.
- Versatile as both a base and top coat, adds a brilliant shine.
- Ideal for those with naturally long, strong nails to prevent breakage.
- Offers a healthier alternative to acrylic nails.
Cons
- Some users may experience bubbling, potentially due to old product.
Ingredients
Ingredients can vary by product variation and may change at any time by the manufacturer. For the most complete and up-to-date list of ingredients, refer to the product packaging.
To analyze individual ingredients, use INCIDecoder.
Ingredients: Ethyl Acetate, Acrylates Copolymer, Butyl Acetate, Nitrocellulose, Butylphthalimide, Isopropylphthalimide, Isopropyl Alcohol, Camphor, Benzophenone-1, D&C Violet No. 2 (CI 60725)
Our Product Rating System
First, Camille (co-creator of Welpr) hand picks cleaner product options from a variety of sources.
Next, we collect information about each product's safety, consumer satisfaction, and eco-ethical standing.
Finally, we run all this information through an algorithm that calculates the Welpr Rating.
Welpr Rating:
5.0/5
Part 1: Product safety
We evaluate safety information from 3rd party organizations (e.g. EWG, Made Safe, etc.). Instead of relying solely on any one of these companies for safety information, we assess all of them.
Part 2: Consumer satisfaction
We scour the web for consumer ratings and reviews to verify products are not only cleaner options, but also effective. Products can either be Above Average, Average, or Below average for their respective category (e.g. cleaning products).
Part 3: Ethics & Environment
When you buy a product, you’re supporting that company with your dollars. We believe it’s important to support ethical companies, so we pool together certifications that verify a company's ethics and environmental impact.
Common Harmful Chemicals in Nail Hardener
Chemical Name
Why it’s harmful
Formaldehyde
Formaldehyde is a colorless, flammable gas with a pungent smell that's naturally produced in small quantities in human bodies and is also known as methanal amongst other names. It's used in the production of various items such as fertilizers, paper, plywood, and urea-formaldehyde resins as well as in some foods and household products like antiseptics, medicines, and cosmetics. Exposure to formaldehyde, which can occur through breathing contaminated indoor air, tobacco smoke, or ambient urban air can lead to respiratory symptoms, irritation of the eyes, nose and throat and has been linked to lung and nasopharyngeal cancer as well as leukemia. The EPA considers formaldehyde a probable human carcinogen (Group B1) and inhaling it can cause bronchospasm and pulmonary edema. Commercially, it's sold as formalin in solutions of 37%, 44%, or 50% and long-term exposure can cause first-degree burns, skin sensitization, squamous cell nasal cancer, and chronic pulmonary obstruction.
Sources:
Formaldehyde and Cancer Risk, Cleaning Products & Indoor Air Quality, No More Toxic Tub, Campaign for Safe Cosmetics: Preservatives, Campaign for Safe Cosmetics: Formaldehyde And Formaldehyde-Releasing Preservatives, Formaldehyde may be found in cosmetic products even when unlabelled, Formaldehyde Found in Popular American Beauty Products, Hair Salons - Formaldehyde in Your Products, Formaldehyde in cosmetic products
Polyacrylamide
Acrylamide is a man-made white crystalline solid primarily used in the production of polymers and copolymers. In humans, it is toxic and irritates the skin and mucous membranes, and can affect the central, peripheral, and autonomic nervous systems leading to symptoms like memory difficulties, confusion, slurred speech, and excessive sweating. It may cause peripheral neuropathy, resulting in loss of sensation and muscle wasting. Recovery after exposure can take months to years. Animal studies indicate acrylamide accumulates in the nervous system, liver, kidney, and male reproductive system, causing degenerative changes. It might disrupt metabolism, induce oxidative stress, cause chromosomal aberrations, and tumor initiation. There is no evidence of teratogenic effects in humans or causing cancer. It has also shown genotoxic effects in some aquatic species like C. Auratus and mussels.
Triethanolamine
Triethanolamine appears to cause occupational asthma and allergic contact dermatitis in machinists and photographers, as well as liver and kidney damage in animals with high-dose feeding. It's noted to be an irritant to the skin, eyes, and respiratory tract, with potential to cause skin sensitization, though the rate of skin sensitization in humans is low. Triethanolamine has low acute toxicity, with median oral LD50 values of 4,190-11,260 mg/kg in rats and 5,300-8,000 mg/kg in guinea pigs, and a median dermal LD50 greater than 2,000 mg/kg in rabbits. Triethanolamine is not carcinogenic, developmental toxicant, or toxic to the reproductive system. However, chronic exposure may lead to liver and kidney damage.
Sources:
Safety assessment of triethanolamine and triethanolamine-containing ingredients as used in cosmetics, Toxicology of mono-, di-, and triethanolamine, Campaign for Safe Cosmetics: Ethanolamine Compounds (MEA, DEA, TEA And Others), The Dirty Dozen: DEA-related ingredients, Chemical Profile, Special Chem, Safety assessment of triethanolamine and triethanolamine-containing ingredients as used in cosmetics
Phthalate
Phthalates, linked to endocrine disruption, reproductive toxicity, and cancer, are banned in the European Union but remain prevalent in U.S. cosmetics. They are widely used in personal care products, such as nail polish, fragrances, and eyelash glue and other products. A significant loophole allows phthalates to be added to fragrances without disclosure. Health concerns include endocrine disruption, developmental and reproductive toxicity, and potential carcinogenicity.
Sources:
Campaign for Safe Cosmetics: Phthalates, Product Profile: Hand Sanitizer, Phthalates in Cosmetics, Phthalates in cosmetic and personal care products: concentrations and possible dermal exposure, A Survey of Phthalates and Parabens in Personal Care Products from the United States and Its Implications for Human Exposure, Phthalates Factsheet, BPA and Phthalates: Chemicals found in our homes
Toluene
Toluene is a clear, colorless liquid that naturally occurs in crude oil and the tolu tree. It's prominent in the production of gasoline, coke from coal, and various consumer products like paints, adhesives, and nail polish. Toluene is even added to gasoline, used to create benzene, and acts as a solvent. However, exposure to toluene, especially from inhalation, can have serious health effects. It primarily targets the central nervous system, inducing symptoms like fatigue, nausea, headaches, and in chronic cases, can cause severe dysfunction. Exposure has also been linked to developmental effects in children, but there isn't enough evidence to conclude its carcinogenic potential. Abuse of toluene can cause permanent brain damage, liver injury, and even potential birth defects or increased risk of spontaneous abortions in pregnant women. Despite these risks, cognitive deficits from toluene exposure below a threshold limit value (TLV) of 50 ppm remain extremely low.
Benzophenone
Benzophenone (BZP) is a photoinitiator, fragrance enhancer, and ultraviolet stabilizer, used in a variety of industrial applications. Despite not being registered as a pesticide in the U.S., it's involved in the production of insecticides and agricultural chemicals. Its toxic effects on humans are scarcely documented, but it presents little hormonal activity on cell lines. Animal studies show it possesses no estrogenic activity, but it can transform into derivatives with such activity under UV irradiation. It did not show reproductive toxicity or carcinogenicity in rats and mice, respectively, even at high doses. It can be bioactivated through specific enzymes. For aquatic life, fathead minnow larvae were more sensitive to BZP, ranking it in the middle of the toxicity order of six benzene derivatives.
Sources:
Benzophenone & Related Compounds, Chemical Profile: Benzophenone, Toxicological evaluation of benzophenone, Benzophenone – information sheet, Proposition 65 Warnings: Benzophenone, OEHHA: Benzophenone, FDA Removes 7 Synthetic Flavoring Substances from Food Additives List, Benzophenone-3, a chemical UV-filter in cosmetics: is it really safe for children and pregnant women? ,
Authors
Camille May, Product Curator
Olushola M. Awoyemi, Medical Reviewer
