Does Cobalt Improve Performance in Horses?

Does Cobalt Improve Performance in Horses?

By Dr Duncan Houston

Cobalt has become one of those substances that sounds scientific enough to be tempting.

It is a real trace mineral. It is part of vitamin B12. It has been discussed in the context of red blood cell production. And that is exactly why it has been misused in racing and performance horses by people hoping it might act like a legal shortcut to better stamina.

The problem is that the theory does not translate into a safe or reliable performance benefit in horses.

The veterinary message is simple: horses need tiny amounts of cobalt as part of normal nutrition, but high-dose cobalt supplementation or injection is not a legitimate performance strategy. It may be dangerous, it may breach competition rules, and it should not be used as a “boost.”

Quick Answer

There is no good evidence that extra cobalt improves performance in horses. A race-fit Standardbred study found that cobalt salt administration did not stimulate red blood cell production, did not increase plasma erythropoietin, and did not improve aerobic or anaerobic performance markers. (Equine Science Center)

Cobalt misuse can be dangerous. Experimental intravenous cobalt chloride administration in horses has been associated with distress, tachycardia, hypertension, arrhythmia, increased cardiac troponin at higher doses, and animal welfare concerns. (Mad Barn USA)

What Is Cobalt?

Cobalt is a trace element. In horses, its best-known role is as part of vitamin B12, also called cobalamin. Vitamin B12 is involved in normal metabolism, neurological function, and blood cell production.

That does not mean cobalt should be treated like a performance drug.

A normal racing diet is generally expected to provide enough cobalt for daily needs, and the National Horseracing Authority’s 2026 guidance states that there is no documented cobalt deficiency in horses and no recognised condition for which cobalt supplementation is indicated. (NHRA)

In practice, that is the key distinction.

Normal trace mineral nutrition is one thing.

Injecting or over-supplementing cobalt because someone thinks it will “oxygen boost” a horse is something completely different.

Why Do People Think Cobalt Improves Performance?

The performance claim usually comes from the idea that cobalt can act as a hypoxia-mimetic substance. In simple terms, some cobalt salts can influence pathways related to the body’s response to low oxygen. In humans and laboratory models, this has created interest around erythropoietin, red blood cell production, and oxygen-carrying capacity.

That sounds impressive.

But horses are not internet theories with legs.

A review of cobalt use in racing horses notes that cobalt’s potential to affect erythropoiesis is part of why it has attracted attention as a doping strategy, but the same review also highlights welfare concerns and major gaps in knowledge about adverse effects and exposure conditions in horses. (ScienceDirect)

The practical veterinary question is not “Can cobalt do something in a cell pathway?”

The question is: Does giving extra cobalt safely improve performance in the horse standing in front of you?

The answer, based on current evidence, is no.

What Does the Research Show?

The most useful performance-focused research found no meaningful benefit.

A study reported by the Rutgers Equine Science Center evaluated cobalt as a possible performance-enhancing drug in race-fit Standardbred horses. The researchers used a sterile cobalt salt solution, given intravenously for three consecutive days, and assessed erythropoietin, red blood cell production, and exercise performance markers. The study found no effect on aerobic or anaerobic performance, no stimulation of red blood cell production, and no effect on plasma erythropoietin concentration. (Equine Science Center)

A separate pharmacokinetic and pharmacodynamic study in 18 horses also found that a single intravenous administration of cobalt had no effect on erythropoietin concentrations, red blood cell parameters, or heart rate in the horses studied. It also found cobalt could remain above baseline for days after administration, making detection relevant for regulators. (HERO)

So the real-world summary is blunt:

The hoped-for blood-boosting effect has not been demonstrated in horses in a way that justifies use.

Why “No Benefit” Does Not Mean “Safe”

This is where the conversation gets important.

Some studies using lower or controlled cobalt doses did not show performance benefit or major adverse effects in that specific protocol. That does not mean high-dose misuse is safe.

The Rutgers summary specifically cautioned that its study did not address the much larger doses suspected in illicit use, and noted that dangerous and life-threatening effects have been reported with higher-dose misuse. (Equine Science Center)

Another experimental study using weekly intravenous cobalt chloride in five Standardbred mares reported visible distress signs after infusion, including pawing, nostril flaring, muscle tremors, and straining. Higher-dose mares developed tachycardia, ventricular tachycardia was observed after the highest dose, and blood pressure increased after all doses. The authors concluded that the degree of hypertension and arrhythmia raised animal welfare and human safety concerns. (Mad Barn USA)

That is the point people often miss.

A substance can be ineffective at improving performance and still be dangerous.

What Are the Potential Risks of Cobalt Misuse?

The main concerns are cardiovascular, welfare, renal, endocrine, and regulatory.

Reported or suspected risks include:

• Distress and agitation

• Muscle tremors

• Tachycardia

• High blood pressure

• Ventricular arrhythmias

• Cardiac strain

• Increased cardiac troponin at higher doses

• Discoloured or bloody urine in some reports

• Potential kidney stress

• Potential endocrine effects

• Unknown long-term consequences

• Competition rule breaches

A review on cobalt chloride doping described serious concerns around high-dose or impure cobalt salts, possible toxicity, possible effects on equine laminar and connective tissue cells, and the lack of adequate information on long-term safety in horses. The authors called high-dose administration irresponsible and unethical. (ScienceDirect)

In practice, the biggest concern is not a theoretical supplement mistake. It is a horse being injected or dosed with a substance in pursuit of performance, without a legitimate medical indication, clear safety margin, or proven benefit.

That is not optimisation.

That is gambling with the horse’s cardiovascular system.

Cobalt, Vitamin B12, and Supplements

This is where owners and trainers can get caught out.

Cobalt is part of vitamin B12, and many oral or injectable products may contain cobalt, vitamin B12, or cobalamin-related ingredients. These products may increase blood or urine cobalt levels, depending on dose, route, timing, frequency, and whether multiple products are used together. The National Horseracing Authority warns that many registered oral and injectable supplements, including vitamin B12 products, contain cobalt and may increase cobalt levels above thresholds for varying periods. (NHRA)

The same guidance states that injectable cobalt or vitamin B12 supplements offer no nutritional advantage because incorporation of cobalt into vitamin B12 occurs naturally in the horse’s hindgut. (NHRA)

The safe mindset is this:

Do not stack products.

Do not assume “vitamin” means harmless.

Do not give race-day or pre-competition supplements without checking the rules.

Do not use unregistered, poorly labelled, internet-marketed, or “undetectable” products.

If a product claims to boost blood, oxygen, stamina, or performance through cobalt, treat that as a red flag, not a selling point.

What Are the Racing Rules Around Cobalt?

Rules vary by country, state, discipline, and governing body, so trainers and owners must check their local authority.

However, cobalt is now actively regulated in racing. The British Horseracing Authority introduced a raceday urinary cobalt threshold after the International Federation of Horseracing Authorities adopted a raceday urinary threshold of 0.1 micrograms, or 100 nanograms, total cobalt per millilitre in urine. (British Horseracing)

The National Horseracing Authority’s 2026 guidance states that internationally adopted thresholds are 100 ng/ml in urine and 25 ng/ml in plasma, and that these thresholds exist to protect horse welfare and racing integrity. (NHRA)

HISA’s Anti-Doping and Medication Control rules in the United States have been implemented and are updated through the official regulatory process, so covered persons should rely on the current official HISA and HIWU rules rather than stable-yard advice. (HISA)

The practical rule is simple:

If the horse competes, check the governing rules before giving any cobalt-containing product.

Risk Framework: How Worried Should You Be?

Low Risk

This is usually low risk if your horse:

• Is on a normal balanced diet

• Is not receiving cobalt injections

• Is not receiving multiple cobalt-containing supplements

• Is not racing or competing under cobalt thresholds

• Has no unexplained clinical signs

• Has supplements reviewed by a vet or nutritionist

Normal dietary cobalt as part of a balanced ration is not the concern.

Moderate Risk

This becomes more concerning if your horse:

• Receives vitamin B12 or “blood-building” supplements

• Has several supplements with overlapping ingredients

• Is close to racing or competition

• Is managed by multiple people who may add products

• Has unclear supplement labels

• Is given products bought online with performance claims

This is the stage where you should stop, list every product, and review them properly before dosing continues.

High Risk

This is high risk if your horse:

• Is receiving cobalt chloride

• Is being injected with cobalt-containing products without a clear veterinary indication

• Is being given products marketed as performance enhancers

• Is receiving high-dose or repeated cobalt or B12 products

• Is racing or competing soon

• Has abnormal heart rate, agitation, tremors, dark urine, or distress after administration

• Is managed in an environment where unlabelled products are used

This horse needs immediate veterinary and regulatory review of the product history.

Critical

This is urgent if your horse develops:

• Marked agitation or distress after injection

• Tremors

• Weakness

• Collapse

• Fast or irregular heartbeat

• Breathing difficulty

• Very high heart rate

• Signs of colic

• Dark, red, or abnormal urine

• Severe sweating or instability

• Sudden poor performance with suspected arrhythmia

This is not a “wait and see” situation. Stop all non-essential supplementation and call a vet immediately.

When Is This an Emergency?

Treat cobalt exposure as urgent if a horse develops acute signs after an injection, supplement, or unknown product.

Red flags include:

• Trembling

• Pawing or marked agitation

• Nostril flaring

• Fast heart rate

• Irregular heart rhythm

• Weakness

• Collapse

• Discoloured urine

• Breathing difficulty

• Severe sweating

• Severe depression

• Signs of shock

• Signs of colic

The experimental intravenous cobalt chloride study reported cardiovascular changes, including tachycardia, hypertension, and arrhythmias, with welfare and human safety concerns. (Mad Barn USA)

If a horse is unstable after any injection or supplement, do not try to “flush it out” yourself. Get veterinary help.

What Else Can Look Like a Cobalt Problem?

Not every poor performance or abnormal recovery episode is caused by cobalt.

Important rule-outs include:

• Cardiac arrhythmia

• Respiratory disease

• Equine asthma

• Exercise-induced pulmonary haemorrhage

• Tying-up or exertional rhabdomyolysis

• Anaemia

• Gastric ulcers

• Pain or lameness

• Poor conditioning

• Heat stress

• Dehydration

• Electrolyte imbalance

• Viral infection

• Low-grade fever

• Overtraining

• Poor nutrition

• Inappropriate supplement use

• Medication side effects

• Illegal or contaminated products

This is why performance concerns should be investigated, not covered up with a “blood booster.”

If a horse is not performing well, the answer is a proper veterinary work-up. Not cobalt. Not mystery injections. Not a product with a shiny label and suspicious promises.

What Should You Do Next?

1. Stop Using Cobalt as a Performance Strategy

Do not administer cobalt chloride or high-dose cobalt products to improve stamina, red blood cells, oxygen delivery, or racing performance.

There is no good evidence this helps horses perform better, and there are clear welfare and regulatory concerns. (Equine Science Center)

2. Review Every Supplement

Make a list of every product the horse receives, including:

• Vitamin B12 injections

• Blood-building products

• Iron supplements

• Mineral supplements

• Electrolyte pastes

• Race-day products

• Recovery products

• Herbal blends

• Imported or internet-purchased products

• Anything given by trainers, grooms, owners, or riders

Many cobalt problems happen because products are stacked without anyone calculating the total exposure.

3. Check the Rules Before Competition

Check your local racing or sport authority.

Do not rely on:

• Stable rumours

• Old withdrawal times

• Product marketing

• “Everyone uses it”

• Internet forums

• Someone saying it is natural

Natural substances can still breach thresholds. Supplements can still count as treatments. And “I didn’t know” is rarely a strong regulatory defence.

4. Record Treatments Properly

If a horse is in a regulated racing environment, supplements and treatments should be recorded according to the applicable rules.

The National Horseracing Authority states that supplement administration constitutes a treatment and must be recorded in the Veterinary Treatment Register on the day of administration. (NHRA)

Even outside racing, good records protect the horse and the people responsible for the horse.

5. Investigate Poor Performance Properly

If the horse is not performing well, investigate the actual cause.

That may include:

• Physical examination

• Lameness evaluation

• Respiratory assessment

• Blood work

• ECG or cardiac work-up

• Endoscopy

• Muscle enzyme testing

• Diet review

• Training review

• Saddle fit assessment

• Recovery and hydration assessment

Poor performance is a clinical sign. It deserves diagnosis, not doping theatre.

6. Avoid Unregistered or “Undetectable” Products

Products claiming to be undetectable, secret, high-dose, blood-building, oxygen-enhancing, or guaranteed to improve performance should be treated as unsafe until proven otherwise.

The NHA specifically warns that unregistered, inadequately labelled, or internet-marketed products claiming performance enhancement or being “undetectable” pose a serious risk and are strongly discouraged. (NHRA)

That is diplomatic regulator language for: do not be silly.

Common Mistakes Owners and Trainers Make

Thinking Cobalt Is Just a Vitamin Issue

Cobalt is part of vitamin B12, but high-dose cobalt administration is not the same as normal nutrition.

Assuming More Is Better

Trace minerals are required in tiny amounts. More is not automatically useful, and with cobalt, more can become dangerous.

Stacking Supplements

Multiple products may contain cobalt or B12. The total exposure matters.

Using Products Close to Race Day

Timing matters, and withdrawal periods depend on dose, route, product type, frequency, and rules.

Trusting Marketing Claims

A supplement label is not evidence. If a product claims performance enhancement through cobalt, be suspicious.

Ignoring Poor Performance

If a horse is not performing, there may be a real medical issue. A “blood booster” can delay diagnosis.

Forgetting Welfare

The horse is not a chemistry experiment. If a product causes distress, tachycardia, hypertension, or arrhythmia risk, it does not belong in a performance plan.

How To Support Performance Safely

Real performance support is usually boring, legal, and effective.

Focus on:

• Correct conditioning

• Gradual fitness work

• Proper recovery days

• High-quality forage

• Balanced energy intake

• Correct protein and amino acids

• Appropriate electrolytes

• Hydration monitoring

• Hoof care

• Dental care

• Respiratory health

• Lameness prevention

• Saddle fit

• Strategic veterinary checks

• Legal medication compliance

• Accurate supplement records

• Rest when the horse needs rest

The best performance horses are not built by mystery injections.

They are built by training, management, nutrition, recovery, and veterinary oversight.

Not very sexy. Very effective.

Will My Horse Be Okay?

If your horse has only been eating a normal balanced diet, cobalt itself is not the concern.

If your horse has received cobalt-containing supplements, the next step is to identify the products, doses, timing, route, and whether the horse is under competition rules. If the horse is clinically normal, your main risks may be regulatory and management-related.

If your horse has received cobalt chloride, high-dose injections, unlabelled products, or stacked B12 and cobalt products, involve your veterinarian. If the horse shows agitation, tremors, abnormal heart rate, weakness, dark urine, collapse, or distress, treat it as urgent.

The earlier you stop the product and investigate properly, the better.

FAQs

Is cobalt banned in horse racing?

Cobalt is regulated in many racing jurisdictions, with thresholds used in blood or urine. The exact rule depends on the governing body, country, and racing code, so always check the current local rules before giving cobalt-containing products. (NHRA)

Does cobalt increase red blood cells in horses?

Current equine studies do not support cobalt as a useful red blood cell booster in horses. One study found no effect on erythropoietin, red blood cell production, or performance markers in race-fit Standardbreds. (Equine Science Center)

Is vitamin B12 the same as cobalt doping?

No. Cobalt is a component of vitamin B12, but supplementing vitamin B12 or cobalt-containing products can still affect cobalt levels and may create regulatory risk. Products should be reviewed by a veterinarian and checked against competition rules. (NHRA)

Can cobalt be toxic to horses?

High-dose cobalt misuse can be dangerous. Intravenous cobalt chloride administration has been associated with distress, tachycardia, hypertension, arrhythmia, and welfare concerns in horses. (Mad Barn USA)

What should I do if my horse was given cobalt?

Stop further non-essential supplementation and contact your veterinarian. Record the product name, dose, route, date, and who administered it. If the horse is competing or racing, check the current governing-body rules immediately.

Final Thoughts

Cobalt is not a shortcut to better performance.

It is a trace element required in tiny amounts as part of normal nutrition. That does not make high-dose cobalt supplementation or injection safe, useful, ethical, or legal in competition horses.

The current evidence does not show a meaningful performance benefit in horses. The welfare concerns are real. The regulatory risks are real. And the idea that a horse’s stamina can be safely improved through cobalt dosing is exactly the kind of stable-yard science that gets horses hurt.

If a horse is not performing, investigate the horse.

Do not reach for cobalt.

---

If you are unsure whether a supplement is safe, legal, or appropriate for your horse, especially if it contains cobalt, vitamin B12, “blood-building” ingredients, or performance claims, ASK A VET™ can help you review the risk before it becomes a welfare or regulatory problem.