KPU stands for Cryptopyrroluria, a multi-metabolic disorder caused by hindgut dysbiosis. When the hindgut can’t produce enough active Vitamin B6 (P5P), the liver cannot detoxify properly. Toxins then build up, causing a wide range of health problems -  from gut upset and skin issues to laminitis, EMS, and chronic “mystery” symptoms.

Because KPU is known as the “disease of a thousand faces,” symptoms vary. Common signs include persistent faecal water, diarrhoea, mallenders/sallenders, skin flare-ups like sweet itch or mud fever, poor hooves, chronic cough, unexplained swelling or lameness, back tension, and horses that don’t respond to normal therapies. EMS and laminitis are often linked to underlying KPU.

Yes - a urine test exists, but it is currently only available in Germany and requires a very short turnaround, which makes it difficult from the UK. In practice, most cases are identified based on history, symptoms, and response to a gut–liver–kidney restoration programme.

The key is restoring the hindgut microbiome so it can produce P5P again. This means 24/7 hay (no haylage), a simple, species-appropriate feedbowl, and supportive nutrients such as zinc, MSM (sulphur), active B6 (P5P), and B12. At EquiNatural, we also offer a structured KPU Reset Programme to guide the process.

No — KPU itself is not genetic. However, a foal can inherit vulnerability if the dam has a compromised hindgut microbiome. The good news is that KPU can be reversed by stabilising the gut and supporting detox pathways.

In KPU horses, the liver’s detox pathway is impaired. Many pharmaceuticals require activation through this process. Without enough P5P, medications may be excreted before they work, or remain in the body as toxins. This explains why some horses develop laminitis or toxic shock after worming or vaccination.