10/07/2025
MYTH: ACTH ALONE TELLS THE WHOLE STORY!
Testing ACTH levels alone seems to be the new shortcut to diagnosing a metabolic or endocrine disorder.
Here’s the truth! No single hormone defines your horse's endocrine health. To properly evaluate thyroid and adrenal function you need a panel of tests, including:
● ACTH, Glucose,Insulin, Cortisol, Leptin
● T3, T4, Free T4 and TSH
Only by looking at these together can you evaluate whether your horse has Cushing’s disease, a thyroid issue, Equine Metabolic syndrome or simply a normal biological response to metabolic diet, stress, or environment.
ACTH is a hormone involved in the chemical stress response, as it triggers the release of cortisol from the adrenals. A stressful environment, chronic pain and iodine deficiency all contribute to a significant increase in cortisol levels which require the involvement of increased ACTH.
Iodine is also one of the most depleted minerals in our soil. It's function is to trigger thyroid hormone production. A blood test related to Iodine deficiency will show a high TSH and T3 but a low T4 and both low Free T3 and Free T4, high ACTH, Cortisol and Glucose.
Accurate Cushings disease diagnostics must include:
✅ Dexamethasone suppression test
✅ Or comprehensive saliva, blood, and urine cortisol testing
The bloodwork will show normal to increased insulin and decreased glucose as well.
Ask your vet to run a complete endocrine panel to avoid taking unnecessary medications.
Equine biochemistry is a language, we need to listen to the whole conversation. 🎯