Zinc is an essential trace element required for optimal brain health and cognition.
In practical terms, adequate levels of zinc in your system work as an antioxidant fighting free radical damage. It helps maintain both male and female hormone balance. And zinc plays a role in neurotransmitter release affecting learning, memory and mood.[i]
When zinc levels are low, you’ll feel fatigued, concentration will be poor, you’ll get sick more often, and simple wounds won’t heal.
Here we’ll investigate why zinc is critical for optimal brain performance. And if you suspect you may be deficient, you may want to consider adding zinc to your nootropic stack. Because your stack may not work as well without it.
- Neurotransmission: Zinc inhibits NMDA receptors which reduces glutamate toxicity. And zinc modulates the activity of proteins such as receptors and enzymes that are involved in the regulation of macromolecules, the regulation of signaling cascades and gene transcription, and transport processes.
- Anxiety & Depression: Low zinc levels are found in depression, and the lower the level the more severe the depression. Zinc increases serotonin uptake in select brain regions which increases the efficacy of antidepressants. And it reduces depression because is increases BDNF.
- Neuroprotectant: Zinc is involved in preserving genomic stability by regulation of redox homeostasis (both oxidant and antioxidant signaling), DNA repair, synthesis, and methylation. Zinc inhibits the production of inflammatory cytokines (including nuclear factor-κB). And zinc protects against cognitive decline due to toxic copper levels.[ii]
Zinc is a trace element that plays an essential role in overall human health and cognition.
Zinc is required for the catalytic activity of around 100 enzymes. It’s involved in immune response, protein synthesis, wound healing, DNA synthesis and cell division.
Adequate levels of zinc are crucial for growth and development when you’re young. And required for proper taste and smell.
Our earliest physical evidence of zinc for therapeutic use comes from the wreck of the ancient ship “Relitto del Pozzino” which sank off the coast of Tuscany around 120 B.C. Archaeologists found the remains of a 2,000 year old medicine chest containing several tin pyxis (cylindrical box with a lid).
Inside one of the tins were five medicinal tablets about the size of an American quarter and perfectly preserved. The pills contained a zinc compound which ancient writings tell us may have been used as an eyewash.[iii]
Zinc deficiency is common around the world including in the USA. This deficiency occurs because we don’t eat enough foods that contain zinc.[iv] Your body needs about 10 – 20 mg of zinc per day because it can’t store zinc.
You get zinc from eating seafood like oysters or lobster. Beef, pork and chicken provide smaller amounts of zinc per serving. And it’s also present in eggs, yogurt, cheese and some nuts.
But not only don’t most of us eat enough zinc-containing food, many plants contain phytates which block the absorption of zinc in your body. So vegetarians are particularly vulnerable to zinc deficiency.
We’ll dive deeper into zinc deficiency and its causes below in the section “How things go bad”. And we’ll cover the easily recognizable symptoms of deficiency as well.
How does Zinc Work in the Brain?
Zinc boosts brain health and function in several ways. But two in particular stand out.
- Zinc is an antidepressant. Zinc plays a role in modulating your brain and body’s response to stress and depression. More than 100 enzymes in your body use zinc to help make DNA, protein synthesis, and cell division.
Zinc is also critical for signaling between and within neurons and other cells in your body. Zinc fingers are present in at least 3% of all your cells. Proteins that contain zinc fingers act as interaction modules that bind DNA, RNA, proteins and other molecules.[v]
Highest amounts of zinc are found in your brain. Particularly your hippocampus. Zinc deficiency can lead to symptoms of depression, aggression, seizures, violence, ADHD, and problems with learning and memory.
A study published in the American Journal of Psychiatry shows that malnourished children exhibit a striking increase in behavioral disorders and aggressive behavior. Kids with nutritional deficiencies demonstrated a 41% increase in aggression at age 8! At age 17, they demonstrated a 51% increase in violent and antisocial behavior.
The malnourished kids weren’t getting enough critical minerals like zinc and iron. Or the B vitamins they needed to develop healthy nervous systems.[vi]
Levels of zinc have been found to be low in those suffering from depression. In fact, the more depressed someone is, the lower the zinc level.[vii]
Several human studies have demonstrated that supplementing zinc with SSRIs help in the effectiveness of these antidepressant drugs. One double-blind, randomized trial with 44 patients with major depression were randomly assigned to receive zinc or a placebo.
At the conclusion of the 12 week study, the researchers found that “zinc supplementation together with SSRIs antidepressant drug improves major depressive disorders more effectively than in patients with placebo plus antidepressants (SSRIs).”[viii]
- Zinc is required for memory formation. Research in the last decade has shown that the presence of zinc in synaptic vesicles of excitatory neurons in the cerebral cortex and hippocampus regulates synaptic plasticity.
Zinc causes the cellular pore to close more slowly than usual. Meaning the vesicle stays open longer. And releases more of the neurotransmitter molecules.
The researchers concluded, “Our results finally provide a connection between zinc and the regulation of neurotransmitter release. This could be important for the formation and storage of memories.”[xi]
One Italian study investigated whether zinc supplementation could help restore memory in stroke patients. 26 patients took 10 mg of zinc daily for 30 days.
On day 30 of the trial, researchers found that zinc supplementation significantly assisted in neurological recovery in the stroke patients.[xiii]
And animal models suggest that zinc supplementation may increase resilience to Traumatic Brain Injury. For treating anxiety, depression, learning and memory deficits caused by TBI.
In this trial, rats with injury to the frontal cortex were fed either a zinc supplement or zinc supplemented diet. The rats were also given a zinc injection an hour after injury.
The research team found that zinc supplementation may be an effective treatment option for improving cognitive impairment and depression following TBI.[xiv]
How things go bad
Zinc deficiency is a problem world-wide including in countries like the United States for several reasons.
Our modern diet typically includes a lot of grains which are usually processed, packaged grain products like cereals. Zinc is found in grains. But this type of zinc is bound to phytates naturally found in these grains. Which block zinc absorption in your body.
So zinc found in whole foods like grain and legumes are not a good source of this essential trace element. And the zinc you get from eating meat can also be blocked if your meal contains grains or legumes.
Eating high carbohydrate foods, especially processed foods, in the USA and other western countries are one of the reasons zinc deficiency is increasing.
If you’re vegan or vegetarian, you’re particularly susceptible to zinc deficiency. If you have chronic digestive problems, leaky gut syndrome, or drink too much alcohol you’re in danger of zinc deficiency.
Zinc deficiency symptoms include:
- Brain fog
- Cravings for salty or sweet foods
- Eating disorders like bulimia or anorexia
- Chronic fatigue syndrome
- Hair loss
- Irritable bowel syndrome
- Impaired growth and sexual development (in kids)
- Infertility & impotence – hypogonadism in males
- Iron non-responsive anemia
- Hormonal issues like bad PMS symptoms
- Hyperactivity (as in ADHD)
- Delayed wound healing
- Impaired adrenal function resulting in anxiety and stress
- Low immunity (you get colds and flu often)
- Pica (eating dirt)
- Poor concentration and memory
- Skin disorders like acne
- Taste and smell problems
- Weight loss or gain
Any of these problems can happen at any age including in the developing child. And can be a result of not getting an adequate supply of zinc.
Zinc to the rescue
Zinc plays a critical role in how well your brain and body function.
Adequate levels of zinc will increase your immunity and help you fight colds. A Cochrane review concluded that “zinc (lozenges or syrup) is beneficial in reducing the duration and severity of the common cold in healthy people, when taken within 24 hours of onset of symptoms”.[xv]
Zinc is a potent antioxidant and anti-inflammatory which helps support healthy cell division and a healthy brain.
Zinc balances hormones which have a direct role in not only your sexual health. But in controlling anxiety, stress, mood and sleep.
Healthy zinc levels help lower inflammation and oxidative stress. The endothelium or thin layer of cells that line blood vessels rely on adequate zinc levels. Supporting a strong blood-brain barrier and cerebral blood flow.
Zinc is involved in protein synthesis which is required by your body to use amino acids from food. Needed for neurotransmitter synthesis and providing the energy needed for mitochondria in every one of your brain cells.
Healthy energy levels and avoidance of chronic fatigue rely on adequate zinc levels.
Low zinc levels are a biomarker for depression. And under conditions of chronic stress, you tend to get rid of zinc through sweat, urine and your saliva.
So if your depressed you may want to try supplementing with zinc. Especially if you’re on SSRs or other antidepressants. Research has found antidepressants and anti-anxiety meds work better when stacked with a zinc supplement.
How does Zinc feel?
Most neurohackers report that supplementing with zinc helps relax them before bed, and they sleep better. Recovery from workouts is faster.
Many report that zinc helps boosts their libido.
Zinc supports an healthy immune system so you can avoid colds and the flu. And if you come down with a bug, zinc will shorten the duration of the illness.
Some neurohackers say zinc keeps allergies from flaring up. And many with skin problems say zinc supplementation reduces acne because it’s anti-inflammatory and antibacterial.
If you are Adult ADHD you may experience a decrease in anxiety or perception of stress. And notice an improvement in mood.
One thing to note from all the research is that improvements from using zinc only manifest if your zinc deficient. With our modern diets, chances are you are deficient. See “Dosage Notes for more”.
Zinc’s role in anxiety & depression
The latest theory suggests that depression is associated with decreased neurogenesis and enhanced neurodegeneration. Which in part is the result of inflammation.
And lately there is mounting evidence that depression could be related to decreased zinc levels.[xvi]
With an overabundance of glutamate we get a decrease in GABA, BDNF, and nerve growth factor. This excitotoxicity is thought to be responsible for seizures, migraines, dementia, anxiety, depression and bipolar disorder.
A double-blind, placebo controlled trial in Japan worked with 30 women to study the effect of zinc supplementation on mood. Half of the women took a multivitamin. And the other half received a multivitamin with 7 mg of zinc per day for 10 weeks.
The women who took the multivitamin/zinc combo showed a significant reduction in anger, hostility, and depression. The women who took only the multivitamin showed no improvement in mood.[xvii]
Another study with depressed overweight subjects found that depression decreased in those supplementing with zinc. But zinc produced no effect on mood in those who were not depressed in the first place.
Researchers concluded that the improved mood in overweight subjects was likely through increasing BDNF levels using zinc.[xviii]
Zinc may relieve symptoms of ADHD
In the last decade, several studies have been conducted into the role trace elements like zinc and how they play in ADHD. Zinc is required for the production and modulation of melatonin which helps regulate dopamine function.[xix]
So the theory is that those with ADHD may benefit from supplementing with zinc.
A double-blind, placebo controlled trial in Turkey was conducted with 400 boys and girls with a primary diagnosis of ADHD. Half the group received 150 mg zinc sulfate for 12 weeks while the control group got a placebo.
The study concluded “Zinc monotherapy was significantly superior to placebo in reducing symptoms of hyperactivity, impulsivity and impaired socialization in patients with ADHD.”[xx]
Another study found that free fatty acids and zinc levels were lower in those with ADHD. But concluded that they didn’t know if zinc deficiency was the principal cause of ADHD. Or a secondary finding.
A study in Croatia again showed that supplementing with 55 mg per day of zinc sulfate help reduce the symptoms of ADHD.[xxi]
Considering the major role zinc plays in everything from cell growth to DNA synthesis to neurotransmitter synthesis and transport. And if your child is diagnosed ADHD and you don’t want to start them on stimulants. You may want to try zinc with a good Omega-3 high in DHA and see if you witness any improvement in ADHD symptoms.
Zinc may prevent autism
Autism spectrum disorders (ASD) range from a severe form called autistic disorder, to a milder form called Asperger syndrome. If a child has specific symptoms of either of these disorders, but does not meet specific criteria for either, the diagnosis is called pervasive developmental disorder not otherwise specified (PDD-NOS).
This complex disease can be inherited, but likely also involves environmental factors.[xxii]
A study published in Biomarker Insights in 2011 worked with 79 autistic subjects to study the association between copper and zinc plasma levels and individuals with autism, Asperger’s and PDD-NOS.
Participants in the study were tested for levels of zinc, copper and antioxidants. Then based on their deficiencies, they were prescribed the appropriate dose of antioxidants (Vitamin C, E, B6 as well as Magnesium, and Manganese if warranted). And they were given zinc picolinate daily for at least 8 weeks.
At the conclusion of the therapy, those with autism and PDD-NOS had significantly lower levels of copper. All three groups had higher levels of zinc.
Severity of symptoms decreased in autistic individuals following zinc and Vitamin B6 therapy with respect to awareness, receptive language, focus and attention, hyperactivity, tip toeing, eye contact, sound sensitivity, tactile sensitivity and seizures.
Interestingly, none of the symptoms in the Asperger’s patients improved after therapy.[xxiii]
Recommended dosage is 30 mg of zinc daily, balanced with 2 mg of copper.
Vegans and vegetarians take note: don’t count on getting any benefit from zinc supplied by vegetables because the phytates in veggies block zinc absorption in your body.
Your body needs zinc, but too much zinc is toxic. And it’s difficult to test for zinc using lab tests.
But there is a simple DIY test first reported in The Lancet that can help you determine zinc levels. Premier Research Labs sells a Liquid Zinc Assay that is available from most local and online vitamin shops.
You taste a teaspoon of Zinc Assay and depending on how the liquid tastes, you can assess your levels according to their guide.
Clearly there is a sweet spot for zinc consumption, and more is definitely not better. More than 50 mg per day can throw off your copper levels, mess with iron function, and reduce immune function.
Zinc toxicity typically happens when you take too much zinc. And can result in abdominal cramps, diarrhea, headaches, loss of appetite and vomiting.
Antibiotics like Cipro® and tetracycline interact with zinc. Inhibiting the absorption of both zinc and the antibiotic.
Zinc can reduce the absorption of the rheumatoid arthritis drug penicillamine. To prevent this interaction you should take your zinc supplement at least 2 hours before or after you take your arthritis meds.
Some diuretics can increase urinary excretion of zinc by as much as 60%. Prolonged use of these drugs can severely deplete your zinc levels.
Zinc can raise your blood pressure. And too much zinc for men can be anti-androgenic, and will over inhibit DHT. Resulting in symptoms often associated with using the hair growth drug finasteride.
Men should also note that too much zinc can dull nerves including nerves in your penis. Because excess zinc can over-inhibit NMDA receptors.
Zinc is sold as zinc gluconate, zinc sulfate, zinc ascorbate, zinc picolinate and various other forms.
- Zinc Ascorbate 15%
- Zinc Bisglycinate 25%
- Zinc Carbonate 52%
- Zinc Citrate 31%
- Zinc Chloride 48%
- Zinc Sulphate 22%
- Zinc Picolinate 20%
So if you’re using a Zinc Picolinate 50 mg tablet, your body may only get about 20% of that zinc for use by your cells.
But more importantly is the fine balance between copper and zinc. Zinc reduces the amount of copper your body absorbs because copper competes with zinc to bind with metallothionein (binding protein that brings zinc into the cells).
The ratio of copper and zinc in your body is more important than the amount of each.
Nootropics Expert Recommendation
We recommend using Zinc as a nootropic supplement.
Your body does not make Zinc on its own. So to get its benefits it needs to come from your diet. Or you must take it as a supplement.
Zinc is especially helpful for treating anxiety and depression. Studies have demonstrated that zinc levels are low in those dealing with depression. And the lower the zinc level, the more severe the depression.
Studies have also shown that if you are having limited success using prescription anti-anxiety drugs or antidepressants that you may increase their effectiveness by supplementing with zinc.
Zinc is also particularly useful in helping alleviate the hyperactivity part of ADHD. Impaired impulsivity and socialization get a boost as well.
Zinc is also required for efficiently encoding and retrieving memories.
Zinc deficiency is a problem worldwide. Especially if you’re vegan or vegetarian.
But too much zinc is toxic. Keep your dose of zinc below 50 mg per day. And stack it with 2 mg of copper to keep your copper/zinc ratio stable.
[i] Ren L., Pour M.D., Majdi S., Malmberg P., Ewing A.G. “Zinc Regulates Chemical-Transmitter Storage in Nanometer Vesicles and Exocytosis Dynamics as Measured by Amperometry.” Angewandte Chemie (International Edition in English) 2017 Apr 24;56(18):4970-4975. (source)
[ii] Brewer G.J., Kaur S. “Zinc Deficiency and Zinc Therapy Efficacy with Reduction of Serum Free Copper in Alzheimer's Disease” International Journal of Alzheimer’s Disease. 2013; 2013: 586365. (source)
[iii] Giachi G. et. El. “Ingredients of a 2,000-y-old medicine revealed by chemical, mineralogical, and botanical investigations” Proceedings of the Natural Academy of Sciences of the United States of America vol. 110 no. 4 > Gianna Giachi, 1193–1196 (source)
[vii] Szewczyk B., Kubera M., Nowak G. “The role of zinc in neurodegenerative inflammatory pathways in depression.” Progress in Neuro-psychopharmacology and Biological Psychiatry. 2011 Apr 29;35(3):693-701. (source)
[viii] Ranjbar E., Kasaei M.S., Mohammad-Shirazi M., Nasrollahzadeh J., Rashidkhani B., Shams J., Mostafavi S.A., Mohammadi M.R. “Effects of zinc supplementation in patients with major depression: a randomized clinical trial.” Iranian Journal of Psychiatry. 2013 Jun;8(2):73-9. (source)
[ix] Pan E., Zhang X.A., Huang Z., Krezel A., Zhao M., Tinberg C.E., Lippard S.J., McNamara J.O. “Vesicular zinc promotes presynaptic and inhibits postsynaptic long-term potentiation of mossy fiber-CA3 synapse.” Neuron. 2011 Sep 22;71(6):1116-26. (source)
[xi] Ren L., Pour M.D., Li X., Malmberg P. Ewing A.G. “Zinc Regulates Chemical-Transmitter Storage in Nanometer Vesicles and Exocytosis Dynamics as Measured by Amperometry.” Angewandte Chemie (International Edition in English). 2017 Apr 24;56(18):4970-4975 (source)
[xii] Tahmasebi Boroujeni S., Naghdi N., Shahbazi M., Farrokhi A., Bagherzadeh F., Kazemnejad A., Javadian M. “The effect of severe zinc deficiency and zinc supplement on spatial learning and memory.” Biological Trace Element Research. 2009 Jul;130(1):48-61. (source)
[xiii] Aquilani R., Baiardi P., Scocchi M., Iadarola P., Verri M., Sessarego P., Boschi F., Pasini E., Pastoris O., Viglio S. “Normalization of zinc intake enhances neurological retrieval of patients suffering from ischemic strokes.” Nutritional Neuroscience. 2009 Oct;12(5):219-25. (source)
[xiv] Cope E.C., Morris D.R., Scrimgeour A.G., Levenson C.W. “Use of zinc as a treatment for traumatic brain injury in the rat: effects on cognitive and behavioral outcomes.” Neurorehabilitation and Neural Repair. 2012 Sep;26(7):907-13. (source)
[xvi] Szewczyk B., Kubera M., Nowak G. “The role of zinc in neurodegenerative inflammatory pathways in depression.” Progress in Neuro-psychopharmacology & Biological Psychiatry. 2011 Apr 29;35(3):693-701 (source)
[xviii] Solati Z., Jazayeri S., Tehrani-Doost M., Mahmoodianfard S., Gohari M.R. “Zinc monotherapy increases serum brain-derived neurotrophic factor (BDNF) levels and decreases depressive symptoms in overweight or obese subjects: a double-blind, randomized, placebo-controlled trial.” Nutritional Neuroscience. 2015 May;18(4):162-8 (source)
[xx] Bilici M., Yildirim F., Kandil S., Bekaroğlu M., Yildirmiş S., Değer O., Ulgen M., Yildiran A., Aksu H. “Double-blind, placebo-controlled study of zinc sulfate in the treatment of attention deficit hyperactivity disorder.” Progress in Neuro-psychopharmacology & Biological Psychiatry. 2004 Jan;28(1):181-90. (source)
[xxi] Dodig-Curković K., Dovhanj J., Curković M., Dodig-Radić J., Degmecić D. “[The role of zinc in the treatment of hyperactivity disorder in children]. In Croatian Acta Medica Croatica. 2009 Oct;63(4):307-13. (source)
[xxiii] Russo A.J., DeVito R. “Analysis of Copper and Zinc Plasma Concentration and the Efficacy of Zinc Therapy in Individuals with Asperger’s Syndrome, Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS) and Autism” Biomarker Insights. 2011; 6: 127–133. (source)