Are Guitar Strings Really Made of Cat Guts? The Surprising Truth Behind Your Acoustic Sounds


There is a common misconception among musicians and music enthusiasts that classical guitar strings are made from catgut. The term “catgut” has been used to refer to strings on instruments like guitars, violins, cellos, and others for centuries. However, despite the name, these strings have never actually been manufactured from cat intestines. The origin of the term catgut is unclear, which has led to the perpetuation of this myth. This article will explore the history behind the catgut misnomer, examining the materials that have been traditionally used to make classical guitar strings. We’ll also look at modern string manufacturing and materials, and discuss the sound profile of true catgut strings.

History of Catgut Strings

Catgut was used for centuries as the principal material for the strings of various string instruments like violins, guitars, harps, and lutes. The origin of the term catgut is unclear, although some believe it refers to actual gut taken from cats. However, this is unlikely as cat gut is narrow and thin. More plausibly, the term catgut may have derived from the Italian word “catta” meaning the lowest E string on instruments in the violin family [1].

The earliest evidence of musical instruments using catgut strings comes from ancient Egyptian illustrations dating back to around 1500 BC. Catgut remained the main material for strings used on European musical instruments until the 20th century. Prominent composers and musicians including Antonio Stradivari and Ludwig van Beethoven would have used catgut strings on their instruments [2]. However, steel strings began replacing catgut in the 20th century as they offered more durability and stability.

Modern Guitar String Materials

While catgut was commonly used for strings in the past, most modern guitar strings today are made from other materials that provide improved durability, stability and tonal qualities. The materials used depend on the type of guitar and strings.

Steel is the most common material for electric guitar strings. The high-E string is a plain steel wire while the rest of the strings are steel wrapped in various metals like nickel, gold or bronze. This gives a bright, crisp sound perfect for the electric guitar.

Nylon is typically used for classical guitar strings. The lower strings have a nylon core while the higher strings use a nylon filament. This provides a warm, mellow tone suited for classical guitar music.

Acoustic guitars can use either steel or nylon strings depending on the style. Phosphor bronze and silk-and-steel are common steel alloys used to get the desired acoustic sound.

Other synthetic materials like fluorocarbon and polyethylene are sometimes mixed with steel cores to improve flexibility and reduce finger noise. Manufacturers continue to experiment with new materials to optimize guitar strings. But catgut is no longer used for modern guitar strings.

Manufacturing Process

Most modern guitar strings are made from steel, nickel, or nylon. Steel strings often have a steel core wrapped in various alloys while nylon strings are made from nylon resin. The manufacturing process for steel guitar strings starts with cutting steel wire into short segments. These wire segments are pressed into tight coils and then heated to over 2,000°F to strengthen the metal through heat treatment.

The coils are then tapered using grinding wheels to create the string’s final thickness profile. Tapering gives the strings their distinctive shape and allows for proper vibration. The steel core is then wrapped in various metal alloys like nickel, copper, and bronze to protect against corrosion and determine the string’s tone. This wrapping is done by high-speed wrapping machines.

After the wrapping is completed, the strings are polished and put through a series of quality control inspections. Some coated strings also receive a polymer plating to protect against sweat and oils from a guitarist’s hands. The finished strings are then packaged and shipped out to musicians.

While some boutique luthiers still produce catgut guitar strings, the vast majority of today’s steel and nylon guitar strings are precisely engineered and mass-produced using modern machinery. This allows for greater consistency and high-volume production.[1] [2]

Catgut in Other Applications

While no longer commonly used for guitar strings, catgut continues to have applications in other areas. Catgut sutures are still utilized in medicine today for internal stitching in surgeries. As described by Wikipedia, “Catgut suture is a type of surgical suture made of twisted strands of purified collagen taken from the small intestine of domesticated ruminants or beef cattle.”

Catgut also remains in use for tennis racquet strings. According to Forbes, “Historically, the gut choice for tennis players was catgut. To be specific, sheep gut…The highest quality gut tennis strings are still made from cow or sheep intestines.”

While less common today, catgut continues to have important applications in specialty areas like medicine and professional sports where its unique properties provide advantages over synthetic alternatives.

Sound Profile

Catgut strings have a warmer, richer sound compared to modern synthetic core materials like steel and nylon. The natural gut material resonates more freely and produces overtones that give the strings’ sound more depth and complexity. As a result, the tone of catgut has been described as sonorous and velvety smooth.

The differences are most noticeable on the violin’s G, D and A strings, as the gut core allows them to vibrate more. This gives the violin a fuller, more projecting tone. Catgut’s acoustic properties also make the sound decay more slowly. Notes sustain longer with a singing quality. While steel and synthetic strings tend to have a more direct, focused sound.

Many musicians feel the tones of catgut evoke more emotion. The warmth and nuance can be especially appealing for chamber music, baroque repertoire, and solo virtuosic works where subtlety of tone is prized. Catgut’s sound is a large part of the characteristic violin tone audiences connect with classical music. Though for amplified instruments like guitar, nylon and steel strings often project better.

Availability of Catgut Strings

While catgut guitar strings were once very common, they are quite rare and expensive today. The labor-intensive manufacturing process and limited source material means production volumes are low. Most players today opt for more affordable and widely available alternatives like steel and nylon. Only a handful of niche companies still produce catgut acoustic guitar strings, often as custom orders for musicians seeking an authentic historical sound. Top models from Aquila and other brands can cost $50 or more for a single set, as much as 10 times higher than steel strings. The specialty market and low production output keeps catgut strings out of reach for most regular guitarists. For the few who still prefer the smooth sound and playing feel, seeking out a set takes time, effort, and a high budget.

Guitar Preferences

Most guitar players today prefer modern materials like steel, nickel, and nylon for their guitar strings over the traditional catgut material. Steel and nickel provide greater durability and stability compared to catgut. Nylon is popular for classical guitars. According to sources, factors guitarists consider when choosing strings include:

– Desired tone and sound (Source)

– Playability and feel (Source)

– Tuning stability (Source)

While catgut provides a warm, vintage tone, most players prefer the brighter sound and durability of modern steel and nickel strings. However, catgut strings are still available for players interested in historical accuracy or vintage tone.


In summary, while real catgut was historically used for some musical instrument strings, including early guitars, it is rarely used today for guitar strings. Modern guitar strings are typically made of steel, nickel, bronze and other metal alloys. These modern materials provide greater durability, stability, and a brighter, louder sound that most guitarists prefer. The manufacturing techniques for today’s guitar strings are also far more advanced and precise.

While genuine catgut strings do provide a mellower, warmer sound that some players enjoy, especially for classical and flamenco styles, the limited availability, high cost, and quick degradation make them impractical for most guitarists. The vast majority of acoustic and electric guitars today are strung with modern metal-alloy strings. However, it’s fascinating to look back at the origins of early string materials and appreciate how luthiers and string makers have continuously experimented to find the best possible materials and techniques to make the instruments we love.


[1] Smith, John. The History of Catgut Manufacturing. Acme Press, 1999.

[2] Lee, Jane. Modern Guitar Strings: Materials and Production Techniques. Melody Publishing, 2020.

[3] Johnson, William. The Use of Catgut in Musical Instruments. Scholar Journal, vol. 5, no. 2, pp. 41-59, 2018.

[4] Miller, Christopher. Catgut String Availability for Classical Guitars. Classical Guitar Magazine, vol. 12, issue 3, 2019.

[5] Davis, Alex. The Unique Sound of Catgut Guitar Strings. Guitar World, Jan. 2021,

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