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 Strengthener in 2025
Updated:
Aug 28, 2025
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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
Not all products in this category are Welpr Approved, but they’re safer than most. The ones that meet our full standard will have the Welpr Approved tag. View our full standards here.
Find Non-Toxic Nail Strengthener
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 is calculated using online reviews and a Bayesian average across all personal care and cosmetic products on Welpr.
Get Well Nail Recovery - Londontown
Welpr Rating
4.85
/5
Certifications
Highlights
User Satisfaction
Est. Price
$20.00
Product Details
- Helps repair damage from gel, acrylic, or peeling nails with nutrient-rich care.
- Strengthens and protects fragile nails with a breathable barrier coat.
- Uses antioxidant and emollient ingredients to nourish at the surface and below.
- Includes alpha hydroxy acids for gentle resurfacing and brightening.
- Supports long-term nail health, leaving them visibly stronger and healthier.
Pros & Cons
Pros
- Strengthens weak and brittle nails effectively.
- Provides a shiny, professional salon look.
- Dries quickly and stays chip-free for days.
Cons
- Some users found the chemical smell to be strong and lingering.
- A few individuals with already brittle nails experienced increased brittleness.
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, Nitrocellulose, Adipic Acid/Neopentyl Glycol/Trimellitic Anhydride Copolymer, Acetyl Tributyl Citrate, Isopropyl, Sucrose Acetate Isobutyrate, Hea/Ipdi Isocyanurate Trimer/Polycaprolactone Diol Copolymer, Glycolic Acid, Tris-Hea Ipdi Isocyanurate Trimer, N-Butyl Alcohol, Etocrylene, Water, Trimethylpentanediyl Dibenzoate, Malic Acid, Hexanal, Lactic Acid, Panthenol, Magnesium Ascorbyl Phosphate, Chamomilla Recutita (Matricaria) Flower Extract, Calcium Pantothenate, Ferrous Gluconate, Oenothera Biennis (Evening Primrose) Oil, Tocopheryl Acetate, Polyvinyl Butyral, Cucumis Sativus (Cucumber) Fruit Extract, Rapeseed Glycerides, Alcohol Denat, Carthamus Tinctorius (Safflower) Seed Oil, Violet 2 (CI 60725), Allium Sativum (Garlic) Bulb Extract, Biotin
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 is calculated using online reviews and a Bayesian average across all personal care and cosmetic products on Welpr.
Nail Saver - Jason Naturals
Welpr Rating
4.85
/5
Certifications
Highlights
User Satisfaction
Est. Price
$7.48
Product Details
- Hydrates cuticles and nails to prevent breakage.
- Crafted with tea tree oil, sesame seed oil, and safflower seed oil.
- Includes vitamin E for added nourishment.
- Free from parabens, sulfates, phthalates, and petrolatum.
- Always cruelty-free and never tested on animals.
Pros & Cons
Pros
- Promotes healthier, stronger nails with a natural formula free from toxic chemicals.
- Contains tea tree oil for added moisturizing benefits.
- Lovely, subtle scent appreciated by users.
- Proven effective for a variety of nail conditions, including brittleness and discoloration.
- Easy to apply and works well within a regular nail care routine.
Cons
- Some users with sensitivities may find the scent overpowering.
- A few users noted the applicator brush could be stiff initially.
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: Sesamum Indicum (Sesame) Seed Oil (1), Carthamus Tinctorius (Safflower) Seed Oil (1), Tocopheryl Acetate, Melaleuca Alternifolia (Tea Tree) Leaf Oil (1), Glycine Soja (Soybean) Oil (1), Oenothera Biennis (Evening Primrose) Oil, Allantoin
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 is calculated using online reviews and a Bayesian average across all personal care and cosmetic products on Welpr.
Biotin Ultimate Strength Nail Treatment & Strengthener - Nail-Aid
Welpr Rating
4.8
/5
Certifications
Highlights
User Satisfaction
Est. Price
$4.48
Product Details
- Fortifies soft, torn nails and prevents peeling and breaking with biotin vitamin B7.
- Shows visible improvement in nail strength and smoothness in as little as 3 days.
- Dries instantly to a long-lasting, anti-chip finish, allowing you to carry on with your day.
- Can be used alone or as a base and top coat for nail color.
- Easily removed with nail polish remover for hassle-free maintenance.
Pros & Cons
Pros
- Helps nails become strong and less prone to breakage, making it ideal for anyone with brittle nails.
- Promotes noticeable nail growth, perfect for those trying to grow out their nails.
- Quick-drying formula, appreciated by busy individuals who need a fast application.
- Provides a glossy finish that enhances the natural look of nails.
Cons
- Some users report the formula becoming thick and difficult to apply, especially for those who frequently use the product.
- The brush may be too short for some, making it hard to access product at the bottom of the bottle, which might be inconvenient for frequent users.
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, Nitrocellulose, Phthalic Anhydride/Trimellitic Anhydride/ Glycols Copolymer, Isopropyl Alcohol, Acetyl Tributyl Citrate, Stearalkonium Hectorite, Biotin (Vitamin B7), Calcium Pantothenate (Vitamin B5), Acrylates Copolymer, Etocrylene, CI 60725 (Violet 2)
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 is calculated using online reviews and a Bayesian average across all personal care and cosmetic products on Welpr.
Nail Strengthener with Proteins, Minerals, Hyaluronic Acid & Vitamins - NutriNails
Welpr Rating
4.65
/5
Certifications
User Satisfaction
Est. Price
$11.95
Product Details
- Rejuvenating formula with hyaluronic acid for nourished and regenerated nails.
- All-in-one treatment with proteins, minerals, and vitamins for robust and radiant nails.
- Quick and visible results, transforming brittle nails into stronger and more lustrous ones within weeks.
- Effective for adults struggling with nail-biting, promoting growth and repairing damage.
- Essential vitamins and minerals foster nail health and beauty, achieving truly stunning nails.
Pros & Cons
Pros
- Makes nails look beautiful and strong.
- No strong smell, suitable for sensitive users.
- Works well over time for long-lasting, healthy nails.
- Stays intact without peeling, even with frequent cooking and cleaning.
- Highly recommended by multiple users.
Cons
- Patience needed as results can take time for some users.
- Occasional delivery issues may result in damaged products.
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: Sodium Hyaluronate, Keratin, Calcium Pantothenate, Allium Sativum Bulb Extract, Tocopheryl Acetate, Nitrocellulose, Butyl Acetate, Ethyl Acetate, Polyester -23, Adipic Acid, Butyl Acrylate/Styrene Copolymer, Pentaerythrityl Tetraisostearate, May Contain: CI 19140, CI 16035, C142090
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 is calculated using online reviews and a Bayesian average across all personal care and cosmetic products on Welpr.
3 Day Growth Nail Treatment & Strengthener - Nail-Aid
Welpr Rating
4.6
/5
Certifications
Highlights
User Satisfaction
Est. Price
$4.48
Product Details
- Strengthens nails with keratin, a hardening protein, to stop peeling and chipping.
- Promotes healthier, harder, longer nails with visible improvement in just 3 days.
- Dries quickly to an ultra-hard finish, preventing accidental smudges.
- Can be used with nail color for a long-wearing, high-gloss manicure or alone for a natural look.
Pros & Cons
Pros
- Promotes stronger, healthier nails, growing without splits or breakages.
- Quick-drying and provides a nice shine.
- User-friendly and integrates well with natural nails.
- Contributes to noticeable growth and strengthening when used consistently.
Cons
- Some users noted that the polish may chip or peel after a few days and requires reapplication for best results.
- The brush could be longer to access all of the product, which may concern frequent users.
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, Phthalic Anhydride/Trimellitic Anhydride/Glycols Copolymer, Isopropyl Alcohol, Acetyl Tributyl Citrate, Stearalkoniumhectorite, Tocopheryl Acetate (Vitamin E), Cholecalciferol (Vitamin D), Keratin Amino Acids, Hydrolyzed Wheat Protein, Calcium Pantothenate (Vitamin B5), Palmitoyl Grape Seed Extract, Etocrylene, Ci 60725 (Violet 2)
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 is calculated using online reviews and a Bayesian average across all personal care and cosmetic products on Welpr.
The Rehab Nail Primer - tenoverten
Welpr Rating
4.6
/5
Highlights
User Satisfaction
Est. Price
$18.00
Product Details
- Formulated to lock in moisture and boost hydration for healthier nails.
- Horsetail leaf extract helps strengthen weak, brittle, thin nails.
- Free from eight potentially harmful chemicals for peace of mind.
- Natural, cruelty-free, and vegan for ethically-minded users.
Pros & Cons
Pros
- Keeps nails hydrated and prevents brittleness.
- Nourishing formula with natural ingredients like tea tree oil and celery seed extract.
- Vegan, cruelty-free, and 8-free for health-conscious users.
- Can be used alone for a subtle shine or as a base coat.
- Fast-drying with a strong, glossy finish.
Cons
- Some users find the chemical smell overpowering.
- The square bottle may make it challenging to use every last drop.
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, Isopropyl Alcohol, Adipic Acid / Neopentyl Glycol / Trimellitic Anhydride Copolymer, Acetyl Tributyl Citrate, Silica, Apium Graveolens (Celery) Root/Seed Extract, Equisetum Arvense (Horsetail) Extract, Melaleuca Alternifolia (Tea Tree) Oil, N-Butyl Alcohol, Acrylates Copolymer, Benzophenone-1
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 Strengthener
Chemical Name
Why it’s harmful
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.
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
Xylene
Xylene is a colorless, flammable liquid with a sweet odor that can be found in cosmetic products. Its functions include enhancing fragrance and perfuming the skin, as well as serving as a solvent to dissolve other substances in the formulation. However, it's important to note that exposure to xylene can lead to various health issues, including irritation of the eyes, nose, skin, and throat, along with symptoms like headaches, dizziness, confusion, and loss of muscle coordination.
Methylisothiazolinone
Methylisothiazolinone can reportedly cause allergic contact dermatitis in workers who interact with products containing it. This substance is recognized as a contact allergen for consumers using cosmetics that include it. It can cause skin burns and sensitization, and inhaling it may lead to corrosive injuries in the upper respiratory tract and lungs. Ingesting this substance is harmful, and inhalation is toxic. This preservative is linked to the category of isothiazolinones.
Sources:
Antimicrobial agents, triclosan, chloroxylenol, methylisothiazolinone and borax, used in cleaning had genotoxic and histopathologic effects on rainbow trout, Methylisothiazolinone toxicity and inhibition of wound healing and regeneration in planaria, Methylchloroisothiazolinone and/or methylisothiazolinone in cosmetic products, Isothiazolinone Biocides: Chemistry, Biological, and Toxicity Profiles, Methylisothiazolinone and isothiazolinone allergy, Analysis of isothiazolinones in environmental waters by gas chromatography–mass spectrometry, Methylisothiazolinone induces apoptotic cell death via matrix metalloproteinase activation in human bronchial epithelial cells, EU REGULATIONS , Methylisothiazolinone contact allergy: a review, Effects of methylisothiazolinone and octylisothiazolinone on development and thyroid endocrine system in zebrafish larvae, Two Cases of Chloromethylisothiazolinone and Methylisothiazolinone-associated Toxic Lung Injury, An update of the risk assessment for methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) with focus on rinse-off products, Effects of a mixture of chloromethylisothiazolinone and methylisothiazolinone on peripheral airway dysfunction in children, Isothiazolinone preservative: cause of a continuing epidemic of cosmetic dermatitis, Campaign for Safe Cosmetics: Methylisothiazolinone and Methylchloroisothiazolinone
Acetone
Acetone is a colorless, flammable liquid that dissolves in water and has a distinct smell and taste. It is also known as dimethyl ketone, 2-propanone, and beta-ketopropane. This manufactured chemical, which is used to create plastic, fibers, drugs, and other chemicals, can also be found in the environment in plants, trees, volcanic gases, forest fires, vehicle exhaust, tobacco smoke, and landfill sites, with industrial processes contributing more to its presence than natural ones. Acetone can be harmful if absorbed through the skin or inhaled, potentially causing irritation to the skin and respiratory tract, as well as adverse effects on the central nervous system (CNS), liver, and kidneys. The allowable exposure limit is set based on its potential to cause eye and upper respiratory irritation and CNS impairment.
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.
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
