Bit materials get talked about as if each one has a taste and a temperature the horse can’t wait to try. Some of that is fact; much of it is marketing. Here’s what each one is, and where research backs the claims.
Less than the fit and the shape, in most cases. The Your Horse guide to bit materials makes the point that a horse who seems to dislike metal often has the wrong size of bit, or a design he finds uncomfortable. Get the size and thickness right first, then think about material.
The evidence is thin: a 2025 study of carriage horses in Vienna noted that no published analyses had examined how mouthpiece materials affect equine well-being.
The default, and probably still the most common. Its main benefit is durability. Sprenger calls it easy to care for and neutral in taste and smell, and its SATINOX line has a satin, matt mouthpiece.
A sweet iron bit is made to oxidise: in use it develops a thin surface rust, which is said to taste sweet and encourage salivation. It turns brown as it does so, and that’s normal. Dry it after each ride and keep it somewhere dry. Any uneven surface rust should come off before the bit goes back in the horse’s mouth.
Does the horse actually taste sweetness? EquiSearch says that is unknown. On safety, Herholz and colleagues (2019) found the iron content of sweet iron bits did not change significantly over 90 days of normal wear, and saw no reason to expect a toxic release of iron into the mouth.
Choose sweet iron to see whether a little taste encourages a busier mouth, stainless for something that looks after itself. Try the Trust Sweet Iron Loose Ring French Link, or browse all our sweet iron bits.
Plain copper tends to pit, so check it for sharp edges.
Sprenger’s Aurigan is copper, silicon and zinc; its successor Sensogan is copper, manganese and zinc, and Sprenger says it is nickel-free. Sprenger claims both stimulate chewing, and warns that not every golden bit has the same effect. Neue Schule’s fitters describe its Salox alloy as designed to warm to blood temperature and to have no taste or smell.
On warmth, in the Vienna study copper mouthpieces had the highest median temperature over 11 months, and the authors suggest copper may be more comfortable in cool weather. Steel gave the highest single readings in the heat. Look at the Sprenger Sensogan Dynamic RS Jointed, the Stubben Sweet Copper Eggbutt or our copper bits.
Despite the name, it contains no silver. It’s an alloy of copper, nickel and zinc. The nickel is the reason some owners think twice: there is concern it could cause allergic reactions and mouth sores, though we found no study showing it.
Fager recommends titanium for sensitive-mouthed horses that react to other metals, and says it feels very light in the hand. The one trial we found, a small University of Padova study of 18 show jumpers, found no difference in saliva pH between titanium and steel snaffles. The Fager Sally Titanium 2.5 Rings is a good place to start.
Rubber is often chosen for young or sensitive horses. It has a rougher surface, which Sprenger says can cause an “eraser effect” on a dry mouth. Vulcanite is rubber hardened by baking onto the mouthpiece, which makes it stronger and less prone to flaking.
Sprenger’s Nathe bits, such as the Nathe Loose Ring Mullen Mouth, are a smooth, food-safe thermoplastic. Many have a stainless steel core but some don’t, so check the description. Happy Mouth uses plastics with an apple scent, as on the Happy Mouth Loose Ring with Copper Roller.
Softer materials get chewed, and a chewed plastic bit can injure the mouth. Check the mouthpiece after every ride. See our rubber bits.
The metal bits above, sweet iron, Sensogan, sweet copper, titanium and stainless among them, can be borrowed on a 30-day Bit Bank trial. Rubber and plastic bits are sold outright, because they can’t be sterilised to the standard our library needs. If you’re not sure which material to try, ring our Bitting Specialists on 01405 861800, option 3.