If you’re feeling constantly fatigued, getting sick often, having a hard time concentrating, or experiencing unexplained nerve symptoms—but your lab work keeps coming back “normal”—you could be missing a key nutrient: copper.
Though copper is a trace mineral, it plays a critical role in immune health, energy production, brain function, and nerve signaling. Copper deficiency is uncommon but underdiagnosed, especially in people who supplement with zinc, have gut issues, or follow restrictive diets.
In this article, we’ll explain:
- What copper does in the body
- Common symptoms of copper deficiency
- What causes copper levels to drop
- How to test for copper deficiency
- Why it often gets missed
- How functional medicine treats low copper
What Does Copper Do in the Body?
Copper is essential for many biologic functions. It supports:
- Energy production through mitochondrial enzymes
- Iron metabolism and healthy red blood cells
- Immune system function and inflammation control
- Brain and nervous system health, including myelin and neurotransmitters
- Collagen production for healthy bones and joints
Without enough copper, the systems that rely on these processes start to weaken. That’s why symptoms can be so wide-ranging.
Symptoms of Copper Deficiency in Adults
Copper deficiency can present with nonspecific symptoms that are often attributed to other causes. These may include:
- Chronic fatigue, especially in the legs
- Frequent colds, sinus infections, or shingles
- Brain fog, poor focus, and forgetfulness
- Numbness, tingling, or weakness in the hands or feet
- Mood changes or mild depression
- Unexplained anemia or low white blood cell count
- Premature greying of hair
- Bone or joint discomfort
These symptoms may come on gradually, which makes them easy to dismiss—especially when conventional labs appear normal.
What Causes Copper Deficiency?
Copper deficiency in adults is often secondary to other factors. Here are the most common causes:
1. Excess Zinc Supplementation
One of the most common causes of copper deficiency is long-term high-dose zinc supplementation. Zinc and copper compete for absorption in the digestive tract. When zinc intake is too high (usually more than 40–50 mg daily), it suppresses copper uptake and eventually leads to deficiency.
This can happen unintentionally when people use immune-boosting zinc supplements or over-the-counter cold remedies long-term.
2. Gastrointestinal Malabsorption
Copper is absorbed in the stomach and small intestine. Any condition that impairs gut function can lead to poor copper absorption, including:
- Celiac disease
- Crohn’s disease
- Small Intestinal Bacterial Overgrowth (SIBO)
- Chronic diarrhea
- Bariatric surgery
- Long-term use of acid-suppressing medications (PPIs)
3. Copper-Deficient Diets
Copper-rich foods include oysters, liver, dark chocolate, sesame seeds, cashews, and sunflower seeds. Diets that are heavily processed or overly restrictive—such as very low-meat, low-seed, or high-zinc animal-protein diets—may not provide enough copper for long-term health.
How to Test for Copper Deficiency
Copper deficiency is not typically detected with routine blood work. If copper is suspected, targeted functional testing is required. Here are the most useful lab markers:
- Ceruloplasmin – A protein that transports copper; low levels are a strong indicator of deficiency
- Serum or plasma copper – Can be interpreted alongside ceruloplasmin for accuracy
- Zinc-to-copper ratio – Elevated zinc with low copper is a classic pattern seen in deficiency
- Complete blood count (CBC) – May show low white blood cells or anemia
- Iron panel – Copper is needed for proper iron utilization; deficiency may impair iron metabolism
If you’re supplementing with zinc or experiencing unexplained neurologic symptoms or fatigue, ask your provider to run these labs.
Why Copper Deficiency Often Goes Undiagnosed
Most primary care labs do not include copper or ceruloplasmin unless there is a clear reason to test. And because symptoms like fatigue, brain fog, and frequent infections are nonspecific, many people are told it’s just stress or aging.
Even when labs are ordered, copper may appear “within range” without context from ceruloplasmin or zinc levels. Functional medicine providers are more likely to use pattern recognition and personalized testing to catch these imbalances early.
Conventional vs Functional Medicine Approach
Conventional Medicine
In conventional medicine, copper deficiency may only be considered in cases of:
- Severe anemia
- Nerve dysfunction
- Diagnosed malabsorption disorders
Treatment typically involves oral or intravenous copper supplementation, with occasional monitoring of blood levels. The root cause is not always addressed.
Functional Medicine
A functional medicine approach identifies and removes the underlying cause while restoring optimal copper levels.
This includes:
- Evaluating zinc intake and removing excess
- Using bioavailable copper forms (e.g., copper glycinate or copper-rich foods)
- Supporting gut healing to improve long-term absorption
- Balancing copper with other minerals (like zinc, iron, selenium)
- Tracking symptoms and lab markers over time to assess progress
This approach not only corrects the deficiency but reduces the risk of recurrence by optimizing your body’s ability to regulate minerals naturally.
Should You Be Concerned About Copper Deficiency?
You may want to investigate copper deficiency if you:
- Take zinc supplements regularly or long-term
- Have unexplained fatigue, brain fog, or numbness
- Suffer from frequent infections
- Have a history of gut inflammation or poor digestion
- Eat a highly restrictive or processed diet
- Have received “normal” lab results that don’t explain your symptoms
Copper deficiency is treatable—but only if it’s detected. Early testing and a root-cause approach can make a dramatic difference in your energy, cognition, and immunity.
Work With a Functional Medicine Provider
At Resolve Medical, we help patients uncover the root causes of chronic symptoms like fatigue, cognitive decline, and immune dysfunction—even when standard labs appear normal.
If you suspect copper deficiency or want help interpreting your nutrient levels, we offer comprehensive diagnostic testing and personalized treatment strategies through our telehealth programs.
Book a Free Discovery Call to get started.
References:
- Copper Deficiency: An Overlooked Diagnosis
Fujikawa H, et al. Cureus. 2023.
Discusses clinical presentations, diagnosis challenges, and treatment of copper deficiency, especially in neurologic and hematologic settings. - Copper Regulation of Immune Response and Potential Clinical Implication
Liu Y, et al. Biomolecules. 2022.
A detailed review on how copper modulates immune responses and what happens during deficiency. - Copper Deficiency: Like a Bad Penny
O’Donnell K, University of Virginia Nutrition Support Letter. 2020.
Clinically focused resource outlining symptoms, lab interpretation, and treatment strategy in copper-deficient patients. - Copper Deficiency: An Important Consideration in the Differential Diagnosis of Myelodysplastic Syndrome
Fong T, et al. Haematologica. 2007.
Highlights hematologic presentations of copper deficiency that can mimic bone marrow disorders. - Copper Deficiency Anemia: Review Article
Myint ZW, et al. Annals of Hematology. 2018.
Comprehensive overview of copper’s role in blood formation, deficiency syndromes, and therapeutic considerations. - Copper Homeostasis and Cuproptosis in Health and Disease
Chen L, et al. Signal Transduction and Targeted Therapy. 2022.
Explores copper’s emerging role in mitochondrial function, oxidative stress, and systemic health.
