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Vitamin B6 (Plasma) Testing

Vitamin B6 (Plasma) Testing

February 2, 2026
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Do I need a Vitamin B6 (Plasma) test?

Struggling with brain fog, low mood, tingling in your hands or feet, or persistent fatigue? Could your vitamin B6 levels be playing a role?

Vitamin B6 is essential for brain function, nerve health, and energy production. When levels are too low or too high, you may experience neurological symptoms, mood changes, or chronic tiredness.

Testing your vitamin B6 gives you a quick snapshot of whether deficiency or excess is contributing to your symptoms. It's the first step toward personalizing your nutrition, supplements, and lifestyle to support your nervous system and restore your energy.

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If you’ve been postponing blood testing for years or feel frustrated by doctor appointments and limited lab panels, you are not alone. Standard healthcare is often reactive, focusing on testing only after symptoms appear or leaving patients in the dark.

Superpower flips that approach. We give you full insight into your body with over 100 biomarkers, personalized action plans, long-term tracking, and answers to your questions, so you can stay ahead of any health issues.

With physician-reviewed results, CLIA-certified labs, and the option for at-home blood draws, Superpower is designed for people who want clarity, convenience, and real accountability - all in one place.

Key benefits of Vitamin B6 (Plasma) testing

  • Measures active B6 in your blood to assess nutritional status and metabolism.
  • Spots deficiency that may cause fatigue, mood changes, or nerve symptoms.
  • Flags excess B6 from supplements, which can damage nerves over time.
  • Guides treatment for anemia, especially when paired with iron and folate levels.
  • Clarifies unexplained skin rashes, tongue inflammation, or immune weakness.
  • Supports pregnancy planning by ensuring adequate B6 for fetal brain development.
  • Tracks response to B6 therapy in conditions like carpal tunnel or nausea.
  • Best interpreted with homocysteine and vitamin B12 for complete metabolic insight.

What is Vitamin B6 (Plasma)?

Vitamin B6 is a water-soluble vitamin that circulates in your blood in several forms, with pyridoxal 5'-phosphate (PLP) being the most active. Your body cannot make it, so you obtain it from foods like poultry, fish, potatoes, chickpeas, and fortified cereals. Once absorbed, it travels through your bloodstream to tissues throughout your body.

Your body's molecular multitasker

Vitamin B6 acts as a helper molecule (coenzyme) in over 100 enzyme reactions. It plays essential roles in breaking down proteins and building neurotransmitters like serotonin and dopamine, which regulate mood and brain function.

Why your cells depend on it

Beyond the brain, B6 supports red blood cell production, immune function, and the metabolism of fats and carbohydrates. It also helps convert the amino acid tryptophan into niacin (another B vitamin) and assists in maintaining normal levels of homocysteine, an amino acid linked to cardiovascular health.

Measuring plasma B6 reflects your recent intake and current vitamin status, offering insight into whether your body has enough of this vital nutrient to support its many metabolic tasks.

Why is Vitamin B6 (Plasma) important?

Vitamin B6, measured in plasma as pyridoxal-5'-phosphate, is a master regulator of amino acid metabolism, neurotransmitter synthesis, and immune function. It powers over 100 enzymatic reactions that build proteins, produce serotonin and dopamine, form hemoglobin, and maintain the myelin sheath around nerves. Without adequate B6, the brain, blood, and immune system cannot operate efficiently.

When levels drop, the nervous system suffers first

Low plasma B6 disrupts neurotransmitter production, leading to irritability, depression, confusion, and peripheral neuropathy with tingling or numbness in the hands and feet. The immune system weakens, increasing infection risk. Anemia may develop because red blood cells cannot mature properly, causing fatigue and pale skin. Pregnant women with low B6 face heightened nausea and, in severe cases, risk for preeclampsia.

High levels are rare but signal supplement overuse

Elevated plasma B6 almost always reflects excessive supplementation, not dietary intake. Chronic high doses can paradoxically cause sensory nerve damage, with symptoms like unsteady gait and loss of position sense. The body cannot store large amounts, so toxicity builds with prolonged overuse.

B6 connects metabolism, mood, and long-term resilience

Optimal B6 sits comfortably mid-range and supports cardiovascular health by regulating homocysteine, a compound linked to arterial damage when elevated. It also modulates inflammation and hormone metabolism. Sustained deficiency accelerates cognitive decline and increases cardiovascular and immune vulnerability over decades.

What do my Vitamin B6 (Plasma) results mean?

Low vitamin B6 levels

Low values usually reflect inadequate intake, poor absorption, or increased metabolic demand. Vitamin B6 is essential for amino acid metabolism, neurotransmitter synthesis, and red blood cell production. Deficiency can impair the formation of serotonin, dopamine, and GABA, contributing to mood changes, irritability, and cognitive fog. It may also reduce hemoglobin synthesis, leading to microcytic anemia. Pregnant women, older adults, and those with malabsorption conditions are at higher risk.

Optimal vitamin B6 levels

Being in range suggests adequate availability for enzymatic reactions that support nervous system function, immune health, and protein metabolism. Optimal values typically sit in the mid to upper portion of the reference range, reflecting sufficient tissue stores and active cofactor availability without excess.

High vitamin B6 levels

High values usually reflect supplementation, as dietary intake alone rarely elevates plasma levels significantly. Chronic high-dose supplementation can lead to sensory neuropathy, causing numbness, tingling, or difficulty with coordination. Elevated levels may also occur transiently after recent supplement ingestion.

Factors that influence vitamin B6 results

Plasma B6 reflects recent intake and may not capture long-term tissue status. Inflammation, alcohol use, and certain medications including oral contraceptives and some anticonvulsants can lower levels. Assay timing relative to supplement use affects interpretation.

Method: Laboratory-developed test (LDT) validated under CLIA; not cleared or approved by the FDA. Results are interpreted by clinicians in context and are not a stand-alone diagnosis.

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Frequently Asked Questions

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How it works
What should I expect during a blood draw?
  • A trained phlebotomist will guide you through the process.
  • A tourniquet is placed on your arm, the site is cleaned, and a small needle is used to collect blood into one or more tubes.
  • Results are usually ready in about a week.
  • Most people feel only a quick pinch.
  • The needle is removed, gentle pressure is applied, and a bandage is placed.
How do I prepare for a blood draw?
  • Drink plenty of water beforehand — hydration makes veins easier to find.
  • Wear loose sleeves so your arm is easy to access.
  • Follow any fasting instructions you’ve been given.
  • Let us know if you’re on medications, have fainted before, or have needle anxiety.
What should I do after my blood draw?
  • Press gently on the site for a few minutes.
  • Keep the bandage on for 4-6 hours.
  • Skip heavy lifting or strenuous exercise for the rest of the day.
  • Drink extra water to rehydrate.
  • Monitor the site for redness, swelling, or pain.
How do I book a blood draw with Superpower?

Your membership includes:

  • An annual full body test and report across 100+ biomarkers
  • A personalized action plan to optimize your biomarkers and reach your health goals
  • A dashboard to centralize your health data and track changes across a lifetime
  • Access to a health concierge for questions on your plan and help scheduling
  • Plus a marketplace of curated health products and services cheaper than amazon

Many concierge clinics charge $10k – $100k for their services, we’ve built technology to make the world’s best healthcare as accessible as possible via an all-in-one membership.

Where can I take my blood test?

Superpower is currently available in the following US states:

  • Alabama
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Our testing
Does Superpower replace my primary care provider?

Superpower specializes in prevention-based testing and treatments and is not intended for emergency or immediate health issues.

While you will have a Superpower care team, your annual membership is designed to complement a primary care doctor if you have one, not replace them.

We are happy to help you share any test results with an outside provider to ensure you receive well-rounded medical care.

How fast are blood test results and how do I read them?

Your annual lab test panel takes about a week to process. We will text you as soon as they become available in your dashboard. Other types of tests may have different testing windows. The Superpower concierge is your own health assistant who helps answer your questions on your results, ensure smooth scheduling, coordination of any office-based tests, specialist referrals as needed, and navigating you to interface with your care team.

Does Superpower accept health insurance?

Superpower membership and products are all eligible for HSA/FSA funding.

We see Superpower like a gym membership for those committed to prevention and performance. Superpower is a bridge between wellness and healthcare. Health insurance traditionally focuses on reactive care whereas, at Superpower, we believe it’s never too early to start looking out for your long-term health.

What if I want more than 1 blood test per year?

Absolutely — you're not limited to just one. Your membership includes one comprehensive 100+ biomarker blood test each year, but if you'd like to track your progress more closely, you can add extra tests at any time. Each additional full-panel test costs $179. You can order as many as you'd like throughout the year.

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Frequently Asked Questions about Vitamin B6 (Plasma) Testing

What is a Vitamin B6 (Plasma) test measuring, and what does PLP mean?

Vitamin B6 (Plasma) testing measures pyridoxal 5'-phosphate (PLP), the active form of vitamin B6 circulating in your blood. Because B6 is water-soluble, plasma PLP reflects your current available B6 for tissues and gives a snapshot of recent intake plus short-term reserves. It’s used to assess nutritional status, metabolism, and whether symptoms may relate to deficiency or excess.

How does plasma vitamin B6 affect mood, energy, and brain function?

Vitamin B6 supports neurotransmitter production, including serotonin and dopamine, which influence mood, cognition, and stress regulation. Low plasma B6 can disrupt these pathways and contribute to fatigue, irritability, depression, and brain fog. B6 also helps convert food into usable energy through amino acid and protein metabolism, so inadequate levels can reduce metabolic efficiency and worsen low-energy symptoms.

What symptoms can low Vitamin B6 (Plasma) levels cause, especially for nerves and skin?

Low plasma B6 may show up first in the nervous system, causing tingling or numbness in hands and feet (peripheral neuropathy), confusion, irritability, or depressed mood. It can also weaken immune response and contribute to skin findings such as rashes or tongue inflammation. Because B6 is needed for red blood cell maturation, deficiency may also cause fatigue and pale skin related to anemia.

Why can high Vitamin B6 (Plasma) from supplements cause neuropathy, and is food a risk?

High plasma B6 is usually caused by high-dose supplements rather than diet. Long-term excess can lead to sensory neuropathy, including numbness, burning pain, and loss of coordination, and nerve effects may persist even after stopping supplementation. Natural dietary intake rarely causes toxicity. Moderate elevations are less likely to be harmful, but very high, sustained levels increase risk.

What are the most common causes of low plasma vitamin B6 (PLP) results?

Low Vitamin B6 (Plasma) typically reflects inadequate intake, poor absorption, or increased demand. Common contributors include chronic alcohol use, malabsorption conditions, and certain medications. The context specifically notes isoniazid and oral contraceptives as potential factors affecting B6 levels. Pregnancy and lactation increase B6 requirements, so levels may drop without consistent intake or supplementation when appropriate.

How is Vitamin B6 (Plasma) testing used to evaluate anemia with iron and folate?

Vitamin B6 supports hemoglobin formation and red blood cell production, so deficiency can contribute to anemia, including microcytic anemia that may not improve with iron alone. Testing plasma B6 can help guide treatment when anemia is being evaluated alongside iron and folate levels. Pairing these markers can clarify whether low B6 is limiting red blood cell maturation and contributing to persistent fatigue.

Why is Vitamin B6 (Plasma) often interpreted with homocysteine and vitamin B12 tests?

Vitamin B6 sits at a key junction in metabolism, including pathways involved in homocysteine handling. Interpreting plasma B6 alongside homocysteine and vitamin B12 can provide a more complete view of metabolic and nutritional status, especially when symptoms involve energy, mood, cognition, or nerve health. This combined approach helps distinguish overlapping deficiencies and improves insight into broader metabolic function.

How do pregnancy and oral contraceptives affect vitamin B6 needs and test results?

Pregnancy increases demand for vitamin B6, and adequate levels support fetal brain development. People who are pregnant (or planning pregnancy) may be more likely to experience neurologic or mood symptoms if B6 is low. Oral contraceptives are also associated with higher B6 needs and may contribute to lower plasma B6. Testing helps confirm whether intake is sufficient for these higher-demand states.

What factors can skew Vitamin B6 (Plasma) results, like inflammation, kidneys, or supplement timing?

Plasma B6 reflects recent intake and short-term status, so results can shift with supplement timing and recent dietary changes. Inflammatory states and tissue breakdown can raise plasma B6 acutely, while renal function can influence levels as well. Certain medications, including isoniazid and oral contraceptives, may affect B6 status. For best interpretation, results are often considered alongside symptoms and related labs.

Can Vitamin B6 (Plasma) testing help monitor response to B6 therapy for nausea or carpal tunnel?

Yes. Plasma B6 testing can help track response when B6 is used therapeutically, including in situations described in the context such as nausea or carpal tunnel. Monitoring helps confirm whether levels move into an adequate range without drifting into excessive levels that could increase neuropathy risk. It’s especially useful when symptoms are ongoing, supplementation is being adjusted, or deficiency/excess is suspected.

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