How To Strengthen Nails For Classical Guitar 

 April 12, 2024

By  Kale Good

Do you need help with weak, cracking, or brittle nails that make it difficult to get consistent results and progress from your classical guitar technique? This article will give some background on what a fingernail is made of, what makes them strong and weak, and how you can strengthen them. 

About Nails

Fingernails are made of many layers of the common keratin protein. Keratin also makes up hair, nails, and the epidermis (plus feathers, horns, and claws, if you have any). The keratin in your fingernails is only 1 of 54 different types of keratin that your body can make. This is why your nails are harder than your skin and softer than a rhino horn despite all being made of keratin. 

However, nail strength can vary tremendously between individuals and even in an individual. The strength of a nail is determined by the layers of keratin in a nail. While an individual's fingernails are typically all about the same strength, toenails are much stronger. This is due to the toenails having more layers of keratin. 

The part of the nail we use to pluck is the free margin or the free edge. The curvature and shape of the free edge are of particular concern to guitarists. The free edge can be arched, hooked, flat, or a combination of these shapes. The curvature of your free edge determines the shape you will need to file to produce an effective "fingertip plectrum" for playing. 

Unfortunately, nothing can be done about the curvature pattern of the free edge; it is determined by the shape of the bone in the tip of your finger (the distal phalanges of the fingers). Fortunately, there is almost always a way to file your fingernails to compensate for the problematic curvature of the free edge. 

Fingernails grow an average of 3 millimeters per month

What weakens nails?


In their natural state, nails hold a lot of water. The optimal water content for nails is 7-12% (in experiments, that number can rise to 50%!).  And, contrary to the image of nails as "hard," they are, in fact, more absorbent than the skin, able to absorb up to 1,000 times more water than skin

Correct water content is essential to nail health, as low moisture leads to brittle nails. However, soaking nails in water is a bad idea! The nail swells when it soaks in large quantities of water. As the nail dries out, it shrinks. This process of swelling and shrinking breaks the links between the keratin layers of the nail, weakening the nail. In fact, this is similar to the problem of a guitar that is too dry; the different woods of the guitar shrink at different rates and cause either the wood or the glue to crack (in fact, assuming everything else is equal, your nails will have the most ideal moisture content at approximate 55% Relative Humidity, just like your guitar)

Maintaining Nail Moisture Equilibrium 101

  1. Wear Gloves Whenever you come in contact with water, soap, or cleaning products. 
  2. Only apply soap to nails if they are dirty.
  3. Avoid Hand Sanitizer, which dries the nails more quickly than soap. 
  4. Using a hydrating hand wash for sensitive skin can minimize the damage done to your hands each time you wash them
  5. Keep a quality hand lotion or cream at the sink and moisturize after each hand wash. Consider carry a small amount in a pocket-sized container for application throughout the day. 


Our nails also contain a small but essential amount of lipids (fats, mainly cholesterol). These lipids help the nail to retain its moisture and fill the gaps between keratin cells. There isn't much to go around at just 0.1-1% lipid content. And every time soap gets on your nails, some is stripped away. 

While other chemicals may be worse for your fingers, the frequency of your contact with water makes it the most likely chemical to damage and weaken your nails. 


Your nails can absorb many common household chemicals, cleaning agents, and oil and water. Heavy cleaning agents like bleach and ammonia, toilet bowl cleaners, oven cleaners, and even All Purpose cleaners are incredibly damaging to your nails. That shouldn't be surprising, as we've already established that even hand and dish soap damage your nails. The solution? Wear gloves while you clean!

In addition to household cleaning chemicals, chemicals found in many nail polishes, nail hardeners, and fingernail glue are also very damaging to your nails. The most problematic is from a nail health perspective formaldehyde. Formaldehyde is actually used in some nail hardeners due to its ability to harden the nail. However, as hardness increases, so does brittleness. Excessive use of nail hardeners that contain formaldehyde will make the nail brittle over time. 

Besides being bad for your nails, excessive exposure to formaldehyde is terrible for your general health.

Unfortunately, many nail care products are full of chemicals that are terrible for your general health. Fortunately, most guitarists refrain from regularly using these products (hardliners, nail polish removers, nail polish, etc.).

However, if you are concerned about these issues, look for at least a "3-Free" nail care product. This indicates that the product does not contain the 3 most concerning chemicals commonly used in nail care products (toyline, formaldehyde, and DBP). You even look for "10-free" nail care products, which exclude the 10 most concerning products (or any number in between).

Ways to strengthen nails

Proper Nail Care

Using the wrong filing tools will cause your nails to chip more easily. On a microscopic level, the wrong filing tool will tear your fingernail, creating a greater surface area for water to enter and weaken your nail. I wrote an entire article that goes into excruciating detail about each common file type; you can read it here. The summary is this: 

  1. Avoid Emery Boards
    1. Use a metal (aka diamond) or Czech-made glass (aka crystal) file to shape the nail
  2. Use a silicone carbide abrasive to polish the nail
  3. either 500 grit open coat sandpaper or MicroMesh.

Another tip is to always keep a file or sandpaper on you and file down any nicks or dings in your nails ASAP. This will prevent them from catching on anything and tearing your nail off, as well as prevent water from infiltrating into the nail via the damaged site. 


A healthy and balanced diet is crucial for nail health. Many vitamin deficiencies can cause weak nails. Fortunately, most people get enough of these vitamins. For those that don't, any basic multivitamin will have almost all these vitamins and minerals (Omega fatty acids being an exception).

 Since nails are made of dead cells, supplements and diet changes do not improve your current nails. You must be consistent with your diet changes and wait 6-12 months for results.

Of course, many people find that their nails grow stronger when they focus on a particular vitamin or nutrient. Biotin is the most commonly touted supplement in nail-care forums. It is the primary ingredient in nail-specific supplements. If you'd like to get your Biotin from your diet, try increasing the quantity of eggs, fish, meat, seeds, and nuts you eat. 

The human body is incredibly good at adapting to minor vitamin deficiencies and imbalances. If your nails are remarkably weak, brittle, and curved, this may be due to an underlying health issue. Please talk to your doctor if this concerns you, especially if you notice a sudden change in nail strength.

Here are common nail complaints and the vitamin deficiencies that lead to them:

  • Brittleness and Dryness: Biotin, vitamin A, vitamin D, calcium, Omega-3 fatty acids. 
  • Dry, dark, Rounded, or Curved nails: B12 (reminder: many people's nails naturally "hook" due to the shape of their fingertip bone)
  • Spoon-shaped (concave) nails: Iron Deficiency. 


This section is short because it's simple but also incredibly important. I can not understate how important this is. Exercise is one of the only things you can do to increase the speed at which your nails grow (you could also get pregnant). By increasing the blood flow throughout your body (specifically to the nail matrix, which generates fingernail cells), your nails will grow faster. They may also be thicker and healthier. 

I'll repeat it: Exercise is one of the only things scientifically (almost) guaranteed to improve your nail health and growth rate.

Nail Applications

You can apply many beauty products to your nails to decrease brittleness and increase strength. They can be categorized into two different objectives: nourishment and structural alterations. Some of these products are soaked on, and some of these products are applied, like nail polish. 


As already explained, proper moisture and lipid (fat) levels are essential to avoid breaking. This is because a dry nail is brittle, and a nail with proper moisture levels will bend more before breaking

A quick way to determine if your nails are well-moisturized is to look at your proximal nail fold (often mistakenly called the cuticle). There should be a thin layer of skin covering the nail's base. If no thin layer of skin extends onto the nail, you likely have a dry proximal nail fold and dry nails. Beyond the problems of dry nails, a disconnected proximal nail fold also allows dirt and bacteria to get lodged between the nail and the skin. This increases the chances of infection and irritation, which harms nail strength and growth. 

Fortunately, there are some simple products and expensive ones (as well as expensive ones) that you can use to moisturize your nails and proximal nail folds at the same time. 

These treatments all make your nail stronger by reducing brittleness, allowing it to bend more before it breaks. 

Creams and ointments are more moisturizing than lotions are. However, they're also more challenging to use during the day due to the greasy residue they leave on your skin.

Common Household Oils

You probably already have some Extra Virgin Olive Oil in your kitchen. If you're looking to moisturize your nails today, with what you have on hand, Olive Oil is an excellent choice. Its high vitamin E content is very good for your nails. I use it about once a week for an overnight-glove soak. 

Jojoba oil is often recommended as the top pick for common oils. While you probably don't have this in the kitchen (it's not cooking oil), you can get some at any drugstore. Jojoba oil is preferred because its chemical structure is similar to sebum (the greasy oil humans naturally make). This makes it very easy for the Jojoba oil to be absorbed into the skin and nails. 

Shea Butter is another moisturizing oil with two particular benefits: it is both an emollient (adds moisture where it's missing) and an occlusive (provides a protective barrier to keep moisture in). It's also commonly available at drug stores or online. 

How to Apply Moisturizers to your nails

in decreasing order of effectiveness

  • Apply a generous amount and wear a nitrate glove overnight
    • the glove will "lock in" the moisturizer for maximum effect. 
  • soak nails in an oil bath for 15-20 minutes. 
  • apply throughout the day, especially after washing hands

Coconut, avocado, and Sunflower oil are healthy for your nails. However, they are much less common than the above oils. And while I've only seen it mentioned once, a London-based podiatrist says Vegetable Oil works fine as a moisturizer, too!

Cuticle Oils: Specialty Oils 

Cuticle and nail oils are typically a mix of sunflower, jojoba, avocado, apricot, safflower, and/or other oils. They often have a fragrance and vitamin D added as well. While these oils offer better miniaturization than the simple oils mentioned above, olive oil is adequate. 

Common Lotions

Any good hand lotion or cream will also be good for nails. It's a good idea to keep a small amount of lotion in a container in your pocket to apply moisturizer throughout the day, especially after washing your nails. 

Horse Hoof Creams

Horse Hoofs suffer many of the same problems our nails do; they get dry and brittle, which makes them prone to cracking and infection. Of course, they also have the nails from horseshoes driven through them regularly!

Horse Hoof Creams were created to help moisturize a horse's hoof and reduce brittleness, breaking, and consequent infection. Of course, hoofs and nails are both made of keratin, and it was only a short time before people started the product as a nail and hand moisturizer. 

Are clear nail tips good/healthy?

Well-moisturized fingernail keratin is transparent. As your fingernail grows to the tip, it becomes incredibly dry, making it white. 

Adding moisture back into the nail can make the keratin clear even at the end of the finger. If this happens due to water exposure, it's terrible for the nail. However, it can also happen after an oil or moisturizer soak; this is okay.  

There are several horse hoof creams; the cheapest ones are marketed towards horse owners, while the more expensive ones are clearly intended for the beauty market (however, even the expensive ones last for a long time). 

Horse Hoof Creams are one of the products I use on my nails regularly. 

Nail Strengtheners and Nail Hardeners

Finally, we arrive at nail strengtheners and nail hardeners; these products have names that are music to the ears of classical guitarists. 

However, it's more complex. These products can easily damage your nails over time and weaken them! 


Nail strengtheners are typically better for your nail's long-term health. However, manufacturers use the terms interchangeably and can use damaging chemicals in both. 

Nail Strengtheners are applied with a brush, much like nail polish. However, they're typically much thinner than nail polish and can absorb quickly. 

Their primary use is moisturizing and strengthening nails between manicures for people who use fake nails so often that their nails have been weakened and thinned considerably. They provide constant nourishment to the nails and prevent moisture from escaping. 

A nail strengthener without any damaging chemicals can safely be used long-term. 

Nail Hardeners come in two varieties; reinforcement hardeners and cross-linking hardeners. Reinforcement hardeners add another layer to the nail; you will instantly feel the results. Cross-linking hardeners create more connections between the keratin proteins in the nail. While this sounds good, remember that as hardness increases, so does brittleness. The most common chemical used to increase hardness is formaldehyde. 

Nail Hardeners and Nail Strengtheners that increase cross-linking are often recommended as short-term fixes to heavily damaged nails. Long-term use will result in a weaker nail. 


That's a lot to say about nails. Leave any questions below in the comments. Otherwise, go forth and make your nails stronger!

Kale Good

Educator and Founder of Good Music Academy.

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