When choosing a bit you should always think about the mouthpiece material as well as fit, side style and mouthpiece type.
The mouthpiece is the part of the bit that goes into the horses mouth and can be made up of a number of different materials.
Bitting materials
Historically bitting horses dates back 5000 years. Bits would have been made from sinew, bone, horn rope, leather or wood. Through the Bronze Age, Iron Age and Steel Age, bitting materials changed with time seeing more substantial bits made from metals of these ages. Nickel was a cheap popular metal used for bitting in the late 1800s until the 1940s. Steel became standard from the 1940s largely as it was more durable, however rusted quickly. Modern bits now use a wide variety of materials which will be discussed below.
Nickel
Nickel bits are still available generally as second-hand and antique bits. This material has an olive colour and never rusts, however, it is a soft material and many antique bits you see made from nickel have stretched joints or distorted rings. They make great decorative pieces nowadays as these edges can be sharp and they don't look as nice as shiny stainless steel bits. Nickel can also cause allergies so has widely stopped being produced. Kangaroo was one of many brands which produced bits from a grey coloured nickel alloy, Eglantine.
Steel and Stainless Steel
Older bits were made from steel, this was cheap but had a tendency to rust very quickly. This was combatted with a mix of iron, nickel and chromium. Today we typically use stainless steel which is 18/8; which is probably the most commonly used stainless steel and contains 18% chromium and 8% nickel. It is corrosion resistant, highly durability and a non-magnetic (British Stainless Steel Association 2025). It is extremely cheap to mass produce, strong, easy to clean, non-toxic and doesn’t rust making it a very good metal for use in horse bits. However, it does still contain nickel which some horses may show allergies to.
High copper content
High copper content bits are an extremely popular choice with horse owners now-a-days. Generally these bits are varying shades of gold depending on the content of copper and other metal alloys used.
These bits are a warmer meaning they adapt to the temperature around them and warm quickly in the mouth to the horses body temperature. Copper mouthpieces are great for dry mouths and those that need encouragement to salivate and respond to the bit.
Copper material is soft, so teeth and other abrasive objects can quite easily mark the metal. It doesn't generally create sharp edges but it can lead to a rough uneven surface which may affect the effectiveness in the mouth. Sometimes the highest copper content bits have their joints stretched therefore regular observation and maintenance is required.
Mixing copper with other alloys makes these bits more durable, such as brass bits, "German Silver" which is a copper and zinc alloy, Neue Schule and Sprenger Bits.
Neue Schule Salox and Sprenger Sensogan
Both Neue Schule and Sprenger have their own branded metal alloy. They are both copper based with trade secrets mixed in. They are Nickel free meaning that they are considered to be more hypoallergenic.
Neue Schule Salox possesses a high thermal conductivity and so warms up quickly within the horse’s mouth. Salox differs from standard stainless steel and other copper alloy bits in that it is a slightly softer metal, allowing it to safely absorb impact forces whilst protecting tooth enamel. This can make the mouthpiece easier to accept by the horse.
Neue Schule aims to keep the bit comfortable but neutral taste. A mouthpiece that doesn’t taste or emit a smell is one that will remain neutral in the mouth. This is aimed to discourage horses chomping and sucking at the bit because it tastes.
There is no evidence that over salivation means the horse is accepting the bit, and the horse cannot physically swallow this excess saliva and breath at the same time. Over-salivation may therefore impact on performance, particularly during faster work.
https://nsbits.com/knowledge_base/salox-sound-science-good-sense
SENSOGAN – the new bit material developed by SPRENGER – is the result of additional development and consequently the improvement of their original material, Aurigan. Aurigan was revolutionary in specifically the taste and salivation aspects to give a more delicate and refined connection to the horse. It is the distinctive composition of copper, manganese and zinc that makes SENSOGAN so special. With a reduced copper content the oxidation process is still maintained, however, the extraordinary combination with manganese results in a smoother and more regulated process of oxidation. Tests show a very positive influence on the horse’s satisfaction, motivation and willingness to perform. The new ingredient manganese is an important micronutrient. As a crucial component and activator of enzymes, manganese is highly relevant for building up connective tissue as well as for the muscle and energy metabolism. It can therefore be helpful in preventing muscle tension and in supporting stress reduction. Beyond that, manganese is needed for the reduction of histamine and can prevent allergic skin reactions. Also, the feed industry discovered manganese to be a promising food additive that is gaining in importance in modern feeding of sport horses.
https://pferdesport.sprenger.de/en/quality-brands/sprenger-brands/?
Sweet iron
Another very popular choice, sweet iron is generally black or blue when new and will always rust. Many people are put off by putting a rusty bit in their horses mouth but this is the whole point if these bits. When rusting, they create a taste which encourages salivation and acceptance of the bit. If they become rough then this may cause tissue damage around the mouth and cause discomfort over time.
Sweet Iron is quite care intensive but easy enough to do. To care for a sweet iron bit it's best to wipe it with bit wipes rather than use a lot of water and soaps. Use a Vegetable or olive oil soaked cloth after cleaning to maintain and reduce the rusting of these bits. They are best stored in a dry location, if this is not possible then wrap in a dry cloth in between uses.
Plastic, rubber and synthetic materials
Synthetic bits are great for youngsters, sensitive and fussy horses that don't like metal in their mouth. They come in a variety of colours and harnesses, from very bendy to very hard to suit your horse’s needs. Some synthetic mouthpieces come quite thick, around 20mm, this may be too thick for some horses but generally horses are very accepting of a thinner synthetic bit.
Nowadays you can get anatomically shaped plastic like the Beris Konnex and Trust Inno sense bits that lie flat and hug the tongue creating a comfortable even pressure throughout the mouth. Happy mouth straight bar bits tend to have two raised bobbles. These are not dressage legal as the bobbles are very hard and dig into the tongue and roof of the mouth.
You should take care to research what is at the core of the bit and ensure you use one which has a steel cable core. Some cheaper brands will use screws or welding, or even nothing at all which can be dangerous in the advent of damage. These bits are very prone to being chewed and tooth marks, if the bit is incorrectly fitted. Do always take care to maintain this type of bit as sharp edges will cause trauma in the mouth and should immediately be replaced. If your bit is being chewed then check the position of the bit in the mouth as it shouldn’t be touching your horses teeth.
Leather
Leather mouthpieces become soft when in contact with warm saliva, this means the bit will mould to the contours of the horse’s mouth. They are great for sensitive, young and fussy mouths. They are a great way to enhance communication and relieve pressure within the mouth and discomfort from metal bits.
To maintain this bit from drying out and cracking you should regularly apply olive oil to keep it supple. Also always fit the stitching to the front incisor teeth, never on the tongue.
Titanium
This metal is becoming increasingly more popular and is very light weight. It has antibacterial properties and is very compatible with horse’s mouths. It encourages saliva production and is a warm metal, enhancing acceptance. They are extremely strong bits, never rust, nickel free, hypoallergenic and non-toxic.
They are great bits for sensitive mouths, horses that react to other metals, (showing red rash or sores despite the bit fitting correctly and light rider hands). The lightness of these bits is said to give quicker response to aids than heavy bits.
Aluminium
Very few bits are made from aluminium, Mikmar bits are made from this metal prior to the advent of titanium. They are very bulky bits so aluminium was chosen as other metals would make the bit too heavy. However, aluminium is considered to dry the mouth out and long term heavy metal exposure may be toxic to horses, all leading to a reduced acceptance of the bit.