Nail Hardener VS. Nail Strengthener


Nail Hardener VS. Nail Strengthener – Which One Is Good?



6 MIN READ | January 10, 2024

Weak nails can be caused by multiple factors- nutrient deficiencies, moisture lack, overexposure to moisture, or health conditions. Fixing such an issue is fairly possible in most cases if they are well taken care of. Although basic maintenance involves just a few things like keeping the nails dry and clean, trimming them properly using good-quality tools and using moisturizer; many individuals include nail hardener or strengthener into the routine.  

While nail hardener is a modified lacquer that turns soft nails into rigid in a short period by using agents and crosslinking with keratin in nails; nail strengthener is a specialized liquid treatment that works to keep the nails well-nourished by penetrating nutritional ingredients into the layers of nails and forming a tough shell, which eventually helps them be flexible but split-resistant. 

Despite having synonymous names, both are different based on multiple factors be it characteristics, appearance, ingredients or the time they take to work. However, since people can confuse one with the other, they may end up using them interchangeably which can lead to disappointment and other problems. So, to clear up this confusion, this article will stress the difference between Nail Strengthener and Hardener.

How Does Nail Hardener Work? Nail Hardener 101

How does nail hardener work

Nail hardeners are thick, clear modified nail enamels with different solvent and resin concentrations, which dry and harden to create a resilient surface. These enamels are short-term treatments that help keep the nails from chipping or breaking. They may have ingredients like toluene, formaldehyde, dibutyl phthalate, nylon (or nylon fibers), polytef, glyoxal, biotin, calcium (or calcium fluoride), dimethyl urea, vitamins, natural oils, and/or titanium-silicone-zirconium polymers.

Nail hardener mainly works in one of two ways- it either binds chains of protein together or reinforces the nail with a hard coat. So, there are two types-

      • Crosslinking hardeners: have contents such as ingredients like formaldehyde, formalin, dimethyl urea, or glyoxal that tie keratin protein in your nails more tightly to reduce the flexibility of your nail plates. They are mainly used as a standalone treatment.

      • Reinforcing hardeners: come with reinforcing fibers like nylon or thiol protein and form a layer over the nails to make their natural structure more rigid. Such products are used as a base coat.

    Benefits Of Using Nail Hardeners

        1. No more splits. Applying nail hardeners can prevent weak, thin nails from chipping or breaking.

        1. Quick fix. They can make soft, bendy nails more rigid within a short time.

        1. Base coat. They can be used as base coat which helps create a smooth surface for applying nail paints.

      Disadvantages Of Nail Hardener

          1. Harsh chemicals. Hardeners mostly have harmful chemicals like formaldehydes that can cause skin irritation, allergic reactions and other issues.

          1. Nail weakening and yellowing. The cross-linking agents of nail hardeners can worsen brittleness and cause yellowing. Sometimes it can be a cause of your damaged nails.

        How Does Nail Strengthener Work Correctly?

        How does nail strengthener work

        Nail strengtheners are serum, polish or cream with a different combination of substances, mostly proteins, vitamins, minerals, antioxidants and oils, which keep the nails hydrated by creating a layer of barrier. Such liquid treatments work to nourish and strengthen natural nails in a healthy way. They have active ingredients like iron, calcium, AHAs, vitamins (like B5 or C), hexanal, glycerin, biotin, keratin and other contents that ensure those benefits.

        Nail strengtheners work by forming a protective, flexible film, supplying nutrients, moisture, and other good agents to the nail plate to reinforce its structure and stimulate growth. They can be used as base or top coat.

        Nail Strengthener Benefits

            1. Promoting nail health. Since strengthener mostly has safe and good ingredients, it helps make the nail stronger from within for a longer period.

            1. Nail hydration. The liquids of nail strengthener create a film that keeps the nail hydrated, improves flexibility and prevents dryness.

            1. Encouraging flexibility. The strengthening effect ensures flexible nail plate that eventually minimizes the risk of nail chipping, breaking and splitting.

          Disadvantages of Nail Strengthener

              1. Slow results. It may take from 7 to 28 days for nail strengthener to show visible results or any kind of improvement.

              1. Harsh chemicals. Some strengtheners may contain harmful chemicals like formaldehyde and dimethylurea that can alter keratin structure in nails and weaken them.

            Nail Strengthener Vs Nail Hardener – Head to Head Differences Between Them

            Nail Strengthener Vs Nail Hardener

            FactorsNail HardenerNail Strengthener
            FunctionDraws out moisture to harden nails making them prone to breakingLocks in moisture to make nails flexible and resistant to breaking
            TargetOuter area of nailInner and outer area of nail
            AppearanceClear, thick lacquerClear polish, serum, cream and polish.
             Common IngredientsFormaldehyde, Ethyl Acetate, Toluene, Vitamins, Biotin, Calcium, Dibutyl Phthalate and/or BiotinKeratin, Collagen, Vitamins, Protein, Nourishing Oils, Calcium and/or Biotin.
            PurposeFor soft, bendy nailsFor unhealthy, impaired nails
            Waiting period10 to 15 minutes1 to 4 weeks


            Function: The contents of nail hardeners bind protein chains and draw moisture out of nails to make them harder whereas the ingredients of nail strengtheners form a tough shell, provide nourishment and allow the nail to be flexible.

            Target: Hardening products target the visible area of the nails and strengthening products focus on both the external and internal area of the nails.

            Appearance: While hardener comes as clear, thick lacquer, strengthener comes in form of clear polish, serum, cream and polish.


            Nail hardeners are made with different formulations with some common ingredients such as formaldehyde, ethyl acetate, toluene, vitamins, biotin, calcium, dibutyl phthalate and/or biotin.

            Most of the hardeners tend to have formaldehyde. It’s a polarizing content that ties to the keratin proteins to harden nail structure through crosslinking. Although such a substance can cause adverse effects, it’s safe as long as its concentration is limited to 2.2% in the lacquer. However, many products have formaldehyde more than 5% which is risky.

            Nail hardeners also have solvents like toluene that help other components dissolve and plasticizers like dibutyl phthalate that stop the lacquer from getting brittle. These two also cause issues like skin irritation, asthma and other health hazards. Hence, lessening the amount of use has been suggested by different experts.

            However, hardeners have good contents such as minerals that prevent brittleness and biotin that improves nail thickness to lessen the risk of splitting.

            Some common ingredients found in nail strengtheners are keratin, collagen, vitamins, protein, glycerin, calcium and biotin. Since strengthening products are mostly free of harmful chemicals like formaldehyde, toluene and dibutyl phthalate, they are considered safer than hardeners.

            Proper nail strengtheners are rich in Keratin that works to stimulate nail health and resilience while providing essential building blocks. They also have calcium and biotin that fortify the brittle nails and keep them from peeling, cracking or chipping.

            Vitamins in the products help repair and restructure impaired nails while strengthening them. Strengtheners may also contain collage that decreases breakage and brittleness by promoting nail suppleness and structure.

            They even have nourishing oils or glycerin that lock in moisture to keep the nails hydrated.


            Nail hardeners are ideal for someone with soft nails whereas nail strengtheners are suitable for those who want to prevent weak, unhealthy nails.

            The hardening products act as a quick fix to transform bendy, breakable nails into rigid ones. So, they are designed for the people who are struggling to grow out their nails as they crack easily.

            On the other hand, strengtheners provide long-term effect by penetrating nutritional contents like keratin into nail layers to make them stronger. They have been formulated for the one who wants to fix unhealthy or impaired nails.

            Waiting Period

            Nail strengtheners work quite slowly and some products may take 1-4 weeks to show signs of improvement. When it comes to nail hardeners, you don’t have to wait to see the result as they work almost immediately by hardening the layer in 10-20 minutes.

            Frequently Asked Questions

            1. Do Nail Hardeners Really Work?

            Yes, nail hardeners have specific agents like formaldehyde which helps harden soft nails by crosslinking keratin in nails.

            Note that, some nail hardening products may cause problems like skin irritation; severe pain and burning sensation in fingers and hands; coughing; and dried out and peeling nails. In that case, remove the hardener by soaking nails in acetone and consult a dermatologist immediately.

            2. What Can I Use Instead of Nail Hardener?

            Nail strengtheners would be a safe alternative to nail hardeners since most products are free of harmful chemicals like formaldehyde and instead contain keratin and other nutrients that help strengthen the nails. You can also make them stronger by using natural ingredients like Argan oil as they have moisturizing and nourishing properties.

            3. Does Nail Hardener Stop Nail Growth?

            Yes, nail hardener can stop nail growth indirectly if it is used incorrectly or not suitable for the person. Although crosslinking agents in hardening products initially work to harden the nail plate, these can cause the nail to suffer from adverse effects like yellowing or plate separation, become weaker and prone to breaking, which eventually slows down or affects nail growth.

            It’s important to use products that have low to no risky chemicals.

            4. Can I Use Nail Hardener Every Day?

            No, you shouldn’t use nail hardener every day since over-usage leads to weakening of nail health. It’s suggested that nail hardeners are applied 1-3 times a week at max and cleaned off every 2 or 3 days to prevent nail-related problems.

            5. What Is A Natural Nail Strengthener?

            A very common natural nail strengthener is castor oil which is rich in vitamin E, Omega-9, fatty acids and protein that helps treat brittle nails and make them stronger.

            Some other natural ingredients are jojoba oil and argon oil which have similar properties working as nail strengtheners.

            Such natural nail strengtheners can be used every day whenever you like.

            Our Thoughts: Which One You Should Use?

            Nail hardeners and strengtheners are sadly used interchangeably due to having the common ingredients and slightly common purposes (i.e. making nails tough).

            However, this may lead to disappointing results as they work differently for different reasons.

            Hardeners are suitable in case you have soft, very flexible nails that break easily and want to turn them more rigid. If your nails aren’t healthy or let’s say they are healthy but you want to make it durable yet flexible, then use nail strengthener.

            It’s advisable to check the ingredients and their concentration to avoid risks of allergies and other health issues. The best would be to get any product that has little to no harmful chemicals.

            Indeed you can use them interchangeably, but it’s better to choose strengthener instead of hardener than go vice versa since it’ll bring healthier and safer benefits.


            Dylan Mustapich is a NYC-based lead esthetician who has been featured in New Beauty, Teen Vogue, Wired, and The Huffington Post. With a lifelong love of all things skin, he is incredibly knowledgeable about skincare ingredients, routine refinement, and personalized skincare, and follows emerging technology closely.

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