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Zinc is an essential trace element required for optimal brain health and cognition.
Zinc is integral to the synthesis of proteins, the regulation of signaling cascades, gene transcription and neurotransmitter transport. It’s involved in DNA repair and synthesis and methylation.
You may think of zinc as a natural cold remedy or the white lip balm you use at the beach. But zinc is needed in small amounts every day to maintain optimal brain function and overall health.
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.
Zinc helps:
- 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]
Overview
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.
Long-term potentiation is a form of synaptic plasticity that has been shown to underlie learning and memory. And zinc in vesicles is critical to proper function of these brain circuits.[ix]
Zinc deficiency is associated with poor memory. And deficiency impairs signaling of BDNF which is also involved in long-term potentiation and memory.[x]
One very recent study revealed that the presence of zinc changes the dynamics of release of neurotransmitters like dopamine at the neuron level.
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]
Read the reviews of neurohackers supplementing with zinc and many report better energy and focus. Clinical research backs this up. But nearly always when correcting a zinc deficiency.[xii]
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 benefits
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 first thing in the morning seems to help many with energy and focus throughout the day.
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 Clinical Research
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]
Zinc deficiency leads to less zinc in neuron synapses which results in an increase in NMDA receptors. This can cause an overload of toxic glutamate.
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]
Zinc Recommended Dosage
Recommended dosage is 30 mg of zinc daily, balanced with 2 mg of copper.
The best food source for zinc by far is oysters. Trailing far behind is other seafood, beef, pork, chicken, some nuts, and some dairy products.
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 Side Effects
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.
Types of Zinc to Buy
Zinc is sold as zinc gluconate, zinc sulfate, zinc ascorbate, zinc picolinate and various other forms.
The percentage of bioavailability for zinc varies by form:
- Zinc Ascorbate 15%
- Zinc Bisglycinate 25%
- Zinc Carbonate 52%
- Zinc Citrate 31%
- Zinc Chloride 48%
- Zinc gluconate 30%
- 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.
For a preformulated vitamin/mineral blend including zinc and copper, designed to optimize your brain and body, I recommend the Performance Lab® NutriGenesis Multi for men or women.
This Whole-Food Multi is Performance Lab’s nutritional starting point, and base of any nootropic stack for restoring and supporting nutrient wellness to your brain and body for peak performance.
The men’s formula contains 22.5 mg of zinc and 1.5 mg of copper while the women’s formula has 10 mg of zinc and 1.5 mg of copper. These are nature-identical minerals just like you’d get from food.
You can see my full review of the Performance Lab® NutriGenesis Multi here.
I also use and recommend: Performance Lab® Zinc
Nootropics Expert Recommendation
I 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.
A great option for optimal zinc and copper for cognitive function is the Performance Lab® NutriGenesis Multi for men or women.
I also use and recommend: Performance Lab® Zinc
Join The Discussion - 158 comments
Bediha
May 12, 2024
Hi David, thank you for your work, I get help a lot from your videos and blog posts.
I have a question regarding the zinc sulfate heptahydrate powder. I would like to prepare a zinc solution same as this product: Premier Research Labs Liquid Zinc Ultra
So I bought a whole bag of zinc sulphate powder and mix it in water according to the the elemental zinc to water ratio.
My question is zinc powder didnt dissolve in the water. It is at the bottom of the bottle like a cloud. Do you happen to know anything about this. Is there a more complex procedure of mixing the water with zinc powder? According to the products label there is only zinc and water.
I always try to make my own supplement from the purest active ingredients to control what s inside and to be cost effective.
David Tomen
May 12, 2024
Here is everything you need to know about zinc sulfate: https://pubchem.ncbi.nlm.nih.gov/compound/Zinc-Sulfate. Including its solubility, what that form of zinc is used for, and its toxicity level.
Andrew Richardson
January 7, 2024
Hey I thought i was getting plenty of Zinc eating chick peas a few times a week and chick chicken for dinner now i don’t want to over do it however supplement if i get enough from food however i have a now supplement that say zinc glycinate 30MG is it safe to take this once every second day i also read that blood levels can show normal but that does not mean brain levels are normal
what do you think would it be safe taking 30MG I don’t have copper or anything to go with that but if i take 30MG once every 2nd or 3rd day would that be a safe amounts i wanted to get 15MG but NOW only sold it at 30MG
I Also had bad insomnia and after i took some i finally slept
its it better to take the supplement without food so it absorbs better i also have IBS
if i took too much would it kill me what i mean is if my levels are fine and i took 30MG would that be a bad thing
David Tomen
January 8, 2024
Andrew, 30 mg zinc per day is safe as long as you also restore the copper that higher doses of zinc depletes. 1.5 or 2 mg of copper is enough. Don’t count on getting all of your nutrients from food because it simply is not there because of industrial farming.
Ami
August 16, 2023
Zinc can inhibit the formation of amyloid? Or have something to do with it?
David Tomen
August 21, 2023
Autopsies of brains with Alzheimer’s found higher concentrations of zinc ions, copper ions and ferritin ions (https://www.nature.com/articles/s41598-018-23122-x#:~:text).
Ami
September 26, 2023
Thanks for the answer.
I have read that Zinc Acetate converts 100 percent of the zinc into the ionic form, which is best for antiviral action. Another form useful for ionic zinc is zinc gluconate, about 70 percent of which is converted to the ionic form.
Ami
September 28, 2023
I’m trying to choose the safest and healthiest form of zinc for the brain.
David Tomen
October 1, 2023
Ami, don’t get stuck in the weeds. Any chelated form of zinc will work. That includes Zinc Bisglycinate, Zinc gluconate, or Zinc Picolinate as long as the supplement is pure. In other words in only contains zinc and possibly a little bit of copper but contains Zero toxics such as silicon dioxide or magnesium stearate.
N. A.
March 31, 2023
You really are a treasure of knowledge! I have 2 questions not related to zinc.
How can we remove mercury (amalgams) from the brain? I have had blackheads in my teeth for many years and the other question is about various parasites that can settle in the brain, without giving particular symptoms like toxoplasma gondii.
What would you both recommend for removing mercury and parasites from the brain?
Thank you from the bottom of my heart for your valuable advice.
David Tomen
March 31, 2023
Use the search function top right and search for “mercury”. You will get a list of supplements that either protect from mercury or helps remove it.
But I have not done any research on brain parasite removal. I suggest doing a Google search or whatever your favorite search engine and search for “best supplements for removing parasites from your brain”.
Ada
February 16, 2023
Hi David! I’ve had all zinc deficiency symptoms
This morning I took 2 zinc sulfate tablets which gave me 90mg total. I feel amazing after 2 hours for the first time in months I felt my libido back, my motivation, energy, concentration, mood was back to pre depression.
I don’t trust blood work for zinc as my results were “normal” last year.
Can you advise me about elemental zinc?
90mg of zinc sulfate (22% bioavaliability) equals 19.8mg of elemental zinc
or I get this wrong and I just consumed 90mg of zinc :O
Company just wrote 90mg zinc sulfate on label.
David Tomen
February 17, 2023
Ada, I suggest staying with the declared amount of zinc in a supplement rather than trying to figure out the dosage based on “elemental zinc”. But you need to be aware that high doses of zinc (anything over 35 mg per day) will suppress copper stores in your body and brain. Which is bad news unless you restore that copper with a low-dose copper supplement. You need 1.5 – 2 mg of copper each time you use zinc.
And I do not recommend continuing with that dose. Because zinc is toxic at high doses. You may feel amazing now but it will catch up to you. Stay with 45 mg per day with 2 mg copper and use that long-term to get zinc’s benefits.
Dan
February 11, 2023
Isn’t it possible to take zinc and copper together? They are antagonists and will interfere with assimilation if taken together.
David Tomen
February 13, 2023
Dan, a good zinc supplement usually contains a low dose of copper because higher zinc doses suppress copper. Copper is added to the supplement to replace what is lost from using zinc.
James
January 12, 2023
Hey David,
Since you said that “the ratio of copper and zinc in your body is more important than the amount of each”, I was wondering if that also applied to Zinc doses that go beyond 50mg?
Meaning if you went beyond 50mg Zinc, would having extra Copper make it fine if the right Zinc/Copper ratio was kept intact?
e.g. since you recommended a ratio of 30-50mg Zinc to 2mg Copper, would 60mg Zinc to 4mg Copper be fine since that ratio would be kept intact?
Or would it still be considered toxic to go beyond 50mg Zinc regardless?
Thanks 🙂
David Tomen
January 13, 2023
James, supplementing with zinc over 35 mg per day can suppress copper in your system. It’s why you see recommendations to supplement with 1 1/2 – 2 mg of copper per day if you are using that amount of zinc. But I do not suggest more than 50 mg per day because too much can be toxic.
Rebecca Burson
January 15, 2023
David—
I am a MD who was diagnosed with ADHD in my late 30s after the birth of my son. I have also been researching magnesium, zinc, B vitamins, and copper balance as well as the relationship to optimal hormone levels. I happen to have a copper IUD for the last 5 years and have been looking through medical journal articles as well as anecdotal information and I can’t seem to find any guidance on whether copper IUDs significantly impact zinc absorption or serum levels. Are you aware of any information regarding copper IUDs and zinc or hormonal fluctuations and these serum levels?
Thanks you,
Rebecca
David Tomen
January 18, 2023
Rebecca, a copper IUD very likely suppresses your zinc to an unhealthy state. So if you continue to use it you may want to consider supplementing with zinc chelate (i.e. zinc picolinate).
And please check out this animal study that talks about women using a zinc supplement instead of a copper IUD: https://pubmed.ncbi.nlm.nih.gov/35929835/
David
December 1, 2022
I suffer from insomnia took 7mg of zinc and finally slept
Would 10MG zinc at night be fine would I need to ad copper at that low level
I am unsure how much I get in my diet alone or if I absorb due to my IBS so would 10 every night be safe without the need to add copper?
David Tomen
December 4, 2022
David, according to my research and understanding of how zinc works in the body any dose under 35 mg per day should not have a negative effect on copper.