Most horses live in a state of one or more mineral imbalances most owners never identify. This is the reference page for the 15 essential minerals horses require, the 7 critical ratios that determine how those minerals function, the 8 toxic heavy metals worth screening for, and the symptoms that point to each. Bookmark this. Send it to your vet.
A horse mineral deficiency is a state of insufficient functional mineral status to support normal physiology. Functional matters more than intake — a horse can eat plenty of copper but absorb little of it if iron levels are blocking copper uptake. The most common pattern in horses is secondary deficiency: adequate intake, poor absorption.
Most equine supplements are designed as if every horse on every farm has the same gaps. Generic "complete" supplements assume average forage, average water, average management. The reality: your horse lives on specific forage from specific soil, drinks specific water, eats a specific feed program, and experiences specific environmental exposure. The right supplement strategy starts with knowing the actual mineral picture, not guessing.
Horses require 15 essential minerals — divided into macrominerals (needed in larger amounts, measured in grams or milligrams per day) and trace minerals (needed in smaller amounts but no less critical).
A single mineral number can mislead. Mineral function is governed by absorption competition and physiological balance — and that's measured by ratios. The same zinc level in two horses can mean very different things depending on what their iron and copper status looks like.
The skin, coat, and hoof ratio. Drives keratin synthesis and color development. Iron overload commonly distorts this ratio.
The hidden-blocker ratio. High iron functionally blocks copper absorption — explains why many "fed enough copper" horses are still copper-deficient in practice.
The bone health ratio. Inverted ratio (more P than Ca, common with high-grain diets) leads to bone resorption and skeletal issues.
The electrolyte/hydration ratio. Critical for working horses, particularly in heat. Imbalance affects cardiac and neuromuscular function.
The neuromuscular/calming ratio. Excess calcium blocks magnesium absorption — relevant for reactive, anxious, and "hot" horses.
Reflects adrenal and stress response status. Often distorted in chronically stressed or hard-working horses.
Reflects thyroid function and overall metabolic rate. Distortions correlate with metabolic disorders and EMS.
Use this table to translate from what you see (symptom) to which minerals are likely involved (cause). Each row links to the dedicated condition site for full diagnostic and management depth.
| Symptom you see | Minerals to investigate | Deep guide |
|---|---|---|
| Dull, faded coat | Copper, zinc, sulfur, selenium. Iron overload may be blocking absorption. | Dull coat → |
| Hair loss / alopecia | Zinc, copper, sulfur. Selenium toxicity for mane/tail loss specifically. | Hair loss → |
| Brittle hooves, lost nails | Copper, zinc, sulfur, biotin. Iron overload is common hidden cause. | Brittle hooves → |
| Cracked hooves | Copper, zinc, sulfur, selenium (toxicity for horizontal cracks). | Cracked hooves → |
| Weak topline / poor muscling | Sulfur, zinc, copper, magnesium, selenium. Amino acids matter equally — work with nutritionist. | Weak topline → |
| Reactive / spooky / anxious | Magnesium, Ca/Mg ratio. Heavy metals (mercury, lead) as neurotoxins. | Anxiety →Spooky → |
| Mare behavior change | Magnesium for support. Always rule out GCT and ulcers first via vet. | Cranky mare → |
| Tying up / muscle issues | Selenium, magnesium, electrolytes. Always rule out PSSM/MFM/RER via genetic testing. | Tying up → |
| Won't sweat (anhidrosis) | Sodium, potassium, magnesium electrolyte status. No proven cure exists. | Anhidrosis → |
| Fat / EMS / insulin resistance | Chromium, magnesium (modest evidence). Iron overload contributes. Vet bloodwork required. | Fat horse → |
| Itchy / pruritus | Zinc, copper, sulfur for skin barrier support. Vet workup for cause. | Itchy →Sweet itch → |
| Suspected heavy metal exposure | Lead, mercury, arsenic, cadmium + 4 others. Hair detects what blood misses. | Heavy metals → |
| Suspected ulcers / behavior change | Magnesium, iron status. Endoscopy required for diagnosis. | Ulcers → |
$49.99 kit. ICP-MS analysis of 42+ elements. Plain-English report.
Heavy metals don't belong in the body in any meaningful amount. Chronic low-level exposure is significantly more common than most owners realize, and bloodwork is poor at catching it. These 8 elements form the heavy metal panel.
For deep coverage of equine heavy metal exposure → heavymetalsinhorses.com
Four steps. About a week of total elapsed time. No needles, no extra vet visit required.
Order the $49.99 hair & mineral analysis kit from Mane Metrics. Resealable bag, pre-labeled return envelope, plain instructions.
2 business days to arriveSnip about 1.5 inches of mane hair close to the crest. Total time at the barn: under 5 minutes. Drop the sealed envelope in any mailbox.
~5 minutesPartner laboratory runs inductively coupled plasma mass spectrometry across 42+ elements — the full panel of essentials, ratios, and heavy metals.
5–7 days at the labEmail-delivered report with color-coded findings, plus a follow-up phone consultation focused on the deficiency picture and what to bring to your vet or nutritionist.
Email + voice debriefThe role of minerals in equine health is one of the most-studied areas of veterinary nutrition. Here are the foundational references behind the recommendations on this site.
The questions horse owners and trainers ask most often when they realize the mineral conversation is more nuanced than the supplement label suggests.
A mineral deficiency is a state where the horse's body has insufficient functional levels of one or more essential minerals to support normal physiological processes. Deficiencies can be primary (inadequate intake) or secondary (adequate intake but poor absorption — often caused by mineral antagonism, particularly iron overload blocking copper and zinc). Common deficiencies in horses include copper, zinc, selenium, sulfur, and magnesium. Diagnosed via hair tissue analysis, blood work, dietary analysis, or clinical signs.
Horses require 15 essential minerals divided into macrominerals (needed in larger amounts) and trace minerals (needed in smaller amounts). Macrominerals: calcium, phosphorus, magnesium, sodium, potassium, chloride, sulfur. Trace minerals: copper, zinc, manganese, selenium, iron, cobalt, iodine, chromium. Boron and molybdenum are also commonly measured. Each plays distinct roles in metabolism, structure, and function.
Copper deficiency is one of the most documented and often-overlooked mineral deficiencies in horses, frequently caused by iron overload from forage, water, or supplements blocking copper absorption. Zinc deficiency frequently accompanies copper deficiency. Selenium deficiency is regional — common in selenium-poor soil regions of the upper Midwest and Pacific Northwest. Magnesium deficiency is widely suspected in performance and stress-related cases.
Signs vary by which mineral is deficient. Common patterns: dull or faded coat (copper), brittle hooves (copper, zinc, sulfur), poor topline (sulfur amino acids, zinc), reactive behavior (magnesium), poor performance (selenium, electrolytes), slow recovery (selenium, vitamin E pairing), skin issues (zinc), and immune compromise (selenium, zinc). The signs are non-specific and overlap; hair tissue mineral analysis identifies which specific minerals are out of range. See the symptom-to-mineral table above.
Seven mineral ratios are clinically important: Zinc/Copper (3-4:1 target — drives skin, coat, hoof health), Iron/Copper (low target — high iron blocks copper), Calcium/Phosphorus (1.5-2:1 target — bone health), Sodium/Potassium (electrolyte balance), Calcium/Magnesium (2:1 target — neuromuscular function), Sodium/Magnesium, and Calcium/Potassium. Single mineral numbers can mislead; ratios reveal absorption and metabolic balance.
Hair tissue mineral analysis (HTMA) measures 42+ elements via ICP-MS spectrometry from a mane hair sample, providing a 90-day metabolic record. Blood work measures circulating levels in real time but misses chronic patterns. Dietary analysis (with an equine nutritionist) measures intake but not absorption. Each method has strengths; together they form the complete picture. HTMA is particularly valued for identifying chronic patterns and heavy-metal exposure that bloodwork misses.
Generic complete supplements are designed for the average horse on average forage in average conditions. They often contain iron (forage is already high in iron), may not match your specific gaps, and can worsen conditions like iron overload that block other minerals. Targeted supplementation based on actual mineral status is more efficient, more cost-effective long-term, and less likely to create new imbalances. Test, then supplement — don't supplement, then guess.
Approximately 9-12 calendar days from order to results: 2 days for kit shipping, 5 minutes to collect, 5-7 days at the lab. You receive an emailed report with color-coded findings, plus a follow-up phone consultation focused on the specific mineral picture for your horse and what to discuss with your veterinarian or equine nutritionist.
Each microsite covers one specific equine health topic. Start with the clinical pillar reference →