Zinc Supplements And Lab Testing: Everything You Need To Know

Hey hey!

This blog post is the third and last installement of my series on zinc, and, covers the topic of 1) supplementing zinc; 2) lab testing your zinc status.



Not everyone is able to perfect their zinc status through just food. If your digestion is compromised, for instance, you might need to supplement with zinc because you're not fully absorbing all zinc from food.

Or, alternatively, you might have eaten a diet very low in zinc-rich foods for a long-time, such as an absence of meats, fish, and shellfish, leading to a huge deficiency. How do you know you've got a deficiency?


You lab test! Then, you supplement to solve the problem as quickly as possible.

More on that dynamic later though...

Let's first recap the previous 2 instalments of this series, on zinc and health and the best zinc foods and signs of deficiency. Here's the summary of my claims:

  • In the first blog post, I argued that zinc played an intrinsic role in human evolution. When evolving from primates, humans increased their zinc consumption because abandoning a mostly plant-based diet for an omnivore one.

    Optimizing your zinc status has tons of benefits, such as improving sleep quality, making you feel happier, boosting energy, increasing fertility, upping your antioxidant status, and more.

    So, you better consume adequate zinc from your diet!

  • The second blog post considered the best zinc foods, such as shellfish, calf's liver, beef, lamb, lobster, and turkey. Nuts, seeds, and beans are reasonable plant-based food sources as well.

    Want to know whether you're deficient?

    Some deficiency signs are having little muscle mass, poor skin, a compromised immune system, getting sick frequently, some forms of thyroid problems, poor sleep, depression, and alterations in your sensory perception, such as poor taste, etc.

    If you've got any of these signs, you might want to continue reading this blog post - especially if you're already consuming tons of zinc-rich foods!

Of course, the blog posts themselves are several thousands of words long and cover these topics in much more detail - including many scientific references. The topics of these blog posts are listed in much more detail below, in the table of contents.

Below, after the table of contents, I'll cover the topics of supplementing with zinc and lab testing. If you're interested, stay tuned and continue reading!


Table Of Contents

Zinc Basics (1st Installment Of Series, Click To Read HERE.)

Understanding Zinc Through Understanding Our (Human) Past
Zinc's Overall Health Benefits--And Diseases Affected By Zinc
Section Finishing Thoughts: Many People Misunderstand Zinc's Role Because They Don't Understand Evolution

Optimizing Zinc Intake  (First Two Parts Are From 2nd Installment Of Series, Click To Read HERE.)

The Best Zinc Foods And Your Daily Zinc Needs
Zinc Deficiency Signs And Prevention
Supplementing With Zinc? ( THIS blog post)
Measuring Your Zinc Levels - Lab Testing 101 (THIS blog post)

Finishing Touch

Conclusion: Zinc Is Not Just An Afterthought



Supplementing With Zinc?

First of all, I'd recommend making sure you get most of your zinc through food - specifically some high-quality animal foods.

In most instances, supplementing with zinc is more dangerous than consuming more zinc-rich foods. Why? Zinc-rich foods such as oysters or beef are often rich in other minerals such as iron or copper as well.

food is naturally balanced in zinc content, supplements such as capsules are often NOTBeef: high-quality zinc, by nature 
balanced by enough iron and copper

Zinc supplements, on the contrary, most often exclusively contain zinc. Taking that zinc supplement without knowing your context can do more harm than good to your health.

Nevertheless, I do want to include an (almost) complete list of zinc supplements in this blog post - judging these supplements on their quality.

The most important criteria for buying a zinc supplement is A) their absorption level; B) whether your supplement is clear from toxins.


First of all, if you cannot properly absorb the zinc you're taking then your action is counterproductive. Secondly, if ingesting zinc means ingesting toxins, you might not be promoting your health in the first place...

Let's first consider my first criteria:

A.) Your zinc needs to be absorbable - i.e., the form needs to be useful.[272]

Some types of zinc are actually used better by the human body than others. 

Below I'll describe the "bad", "good", and "winning" types of zinc supplements.

Let's start with the bad forms of zinc (low utilization by your body):

  • Zinc Picolinate

    One zinc form that I do not recommend is zinc that's paired with "picolinic acid". While you can forget that name, the reason I'm rejecting this zinc form is that the picolinate may remove zinc from the body's stores.[272; 311]

    Zinc picolinate, moreover, can also be toxic to your cells (although you would have to consume large quantities of the substance).[316]

    There are safer zinc forms that do not have the aforementioned issues, so that's why zinc picolinate is subsumed under the "bad" zinc forms.

  • Zinc Oxide.[333; 424; 428]

    Remember my magnesium blog post? In that article, I described a magnesium supplement form called "magnesium oxide" which had very low absorption levels.

    Just like the magnesium oxide garbage form, zinc oxide also has poor absorption levels as well. Don't use zinc oxide when you can get other zinc forms that are both inexpensive and absorb well.

    The absorption of zinc oxide might be the same or (even) lower as the next zinc form I'm considering: zinc sulphate:

  • Zinc Sulphate.[311 325; 423]

    This form has very poor absorption compared to better zinc forms.




  • Zinc Carbonate.[428]

    Poor absorption yet again - in fact, this form is almost unusable by the body. 

    Avoid again...

    I do like to see more studies on this zinc form, as other "carbonate" forms such as calcium carbonate are absorbed very well by the human body. Nevertheless, due to the current evidence, I'm subsuming "zinc carbonate" in the "bad" category.

  • Zinc Pantothenate.[311; 423]

    This form - yet again - seems to be absorbed less well than other zinc alternatives and has not been widely tested.

    Steer clear...

  • Zinc Aspartate.[324; 330]

    This zinc form is bound to "aspartate" which can act as a neurotoxin in your brain. Although absorption is fine, more healthy choices are available.

Let's finally consider some zinc forms that do confer good benefits:

The good forms of zinc:

  • Zinc Orotate.[311; 330]

    Zinc orotate absorbs better than alternatives, such as zinc sulfate or zinc pantothenate. Sadly enough, there's not that much specific research on zinc orotate, although it may be logically inferred that this form should be highly absorbable, just as magnesium orotate is.

    I've written about magnesium orotate in a previous blog post.

    Zinc orotate might be especially great if you're exercising a lot. Why? Zinc orotate may lower fatigue levels.

  • Zinc Carnosine.[234; 328; 329]

    Although more research is needed, this compound may help with reducing gut issues if you have trouble absorbing other zinc forms. 

    Zinc carnosine does appear healing to the gut and might therefore be an ideal choice for people with gut issues.

  • Zinc Methionine.[426; 445]

    This zinc form may be great, but unfortunately, very few high-quality studies can be found on this zinc form.

    In animal studies, there does seem to be a high absorption from this zinc form.

While the zinc supplements in the "good" are fine choices, they are not what I would recommend as the "best". In general, the best zinc supplements do not cost you any extra money compared to supplements found in the "best" category.

Lastly, let's thus consider your best zinc supplement choices:

The zinc winners:

  • Zinc Gluconate.[272; 317; 333; 425]

    Fortunately, zinc gluconate is inexpensive. It's also been established that zinc gluconate has much higher absorption levels than zinc oxide and other "garbage" zinc forms I've treated earlier.

    There's a big upside to gluconate though: zinc gluconate has been tested to be really low in toxic metals such as cadmium.[307The low toxin levels are the biggest upsell of this zinc form.

    Zinc gluconate seems to have either the same or somewhat lower absorption levels than zinc citrate - which I'll treat now:

  • Zinc Citrate.

    The citrate that's added to the zinc directly increases the absorption of zinc.[15] Absorption of zinc citrate is also higher than zinc picolinate.[332] 

    Absorption of this zinc form is equally as high as zinc gluconate. No adverse effects have been found of zinc citrate, so this form is highly recommended.

  • Zinc Glycinate.

    This form seems to have great absorption levels, which may be up to 40% higher than zinc gluconate.[321; 326] 

    Animal studies indicate that glycinate is probably better than zinc sulphate.[322; 323; 325; 328]

I'm not done yet though. Let's look at the second quality that the best zinc supplements should have:

B.) Your zinc supplement should be clear from toxins.

Zinc supplements can contain heavy metals such as "cadmium" in high amounts.


If you're not buying a high-quality supplement, you're massively reducing the benefits you get from a supplement.[307Supplements should be healing--not cause health impairments on their own.

Contrary to what many people think, heavy metals in your body do matter. Let's consider cadmium. Cadmium is eliminated very slowly from your body: half of the dose you ingest stays in your body for 12 years.[308] 

12 years of wreaking havoc...

Fortunately, I've got some important info on zinc supplements:

In general, supplements that contain just zinc are safer than getting zinc from multi-vitamins and multi-minerals.[307

I'm not being pessimistic or partaking in fear-mongering in this section: even prenatal vitamins are often contaminated with toxic heavy metals such as mercury or lead.

Insane but true...

The bottom line is that you should not try to save on (zinc) supplements, by thinking you can get away with as cheap as a product as possible. Zinc supplements are already inexpensive, so there's no reason to try to save as much as you can.

Most people are not buying the cheapest car, cheapest couch, or cheapest house, but they're very quick to opt for the cheapest supplements. That mentality is toxic because your health should be prioritized over and above buying a bigger car.

So what should you do?

What's my solution to buy high-quality supplements that are free from toxins?

Bulk Supplement's zinc gluconate is uber inexpensive, and yet, high quality.

The supplement is also food grade, meaning that it's low in toxic heavy metals such as cadmium, mercury, and arsenic.

Disclaimer: only buy a zinc supplement if you're unable to increase your shellfish and red meat intake. I consider shellfish and red meat the best zinc sources that should be available to most people.

Do you want another zinc forms besides zinc gluconate?

Here you go...

Click the following links to buy that specific product:

Unfortunately, I do not have heavy metal lab tests for these four supplements.


So what's the best time to take a zinc supplement?

If I take zinc supplements, I like to take them at nighttime (before bed). It might be a placebo effect, but I do feel effects from taking a zinc and magnesium supplement right before going to bed--as opposed to during the daytime.

Both magnesium and zinc have a calming effect, which partially explains why many people benefit by taking them before bedtime.

I do want to give you a warning though:

Many of these zinc supplements are dosed very highly, such as 15 or 30 milligrams.

If you're giving such supplements to children, be very careful not to administer them every day. 


Children may only have a need for 5 or 10 milligrams of zinc per day - depending on their age - and will almost immediately end up with a copper or iron deficiency if you're giving them 30 milligrams every day.

Rule: no high-dose zinc supplements for your kids.

You're not doing them a favor if they end up with a copper or iron deficiency. Give your kids oysters or red meat instead.

Lastly, you might be thinking:


"Any other zinc uses I should be aware of?"

Sure, zinc oxide is often used in sunscreens. Zinc oxide is very effective to block out the sun (which you should almost never want to do, as it blocks all different types of ultraviolet light.)

Zinc is also used as an antibacterial substance that's added to products, such as toothpaste and food packaging. 

In general, it's best to avoid these products. No need to use zinc besides internal use...



Measuring Your Zinc Levels - Lab Testing 101

Let's say you're thinking "all right, you've given me the zinc deficiency symptoms, and told me what foods to eat and potential supplements to take. But I want to know whether I'm REALLY deficient." 

In that case, this section is for you...

In this section, I'm including several lab tests that can help you get a better picture of your body's zinc status.

Let's first consider how zinc works in your body. There are about 2,5 grams of total zinc in your body.[353Your bones, skeletal muscle, and liver contain the most net zinc in your body.

Interestingly enough, zinc is turned over up to 125 times per day.[352] 

Zinc is a hard case to measure though--some types of vitamins and minerals are much easier to measure. Vitamin A, for instance, can be measured through your blood plasma, while magnesium is easily testable in your red blood cells.[265; 266] 

With zinc tests, the process is more complicated. It's also difficult to know whether you're deficient in zinc-based on symptoms alone...


For zinc, there's no straightforward symptom that indicates that people have a zinc deficiency in the first place. Sure, you'll sleep worse, have a memory of a person 20 year older than you, and you'll recover slower from workouts.

There's no paradigmatic symptom of zinc deficiency.

In magnesium deficiency, cramps and insomnia might be the most important symptoms. In zinc deficiency, on the contrary, there's a list of 5-20 symptoms. Many of these symptoms may or may not be present - depending on the individual.

There's another problem that complicates going off "zinc deficiency symptoms" all by themselves:

Let's say, for example, that children have problems with their immune system or slowed growth. In that case, these symptoms can entail a zinc deficiency, but can also occur due to several types of cancers or overall malnutrition.

Understanding whether you have a zinc deficiency or not is thus not very straightforward...

In this section, I'll consider several methods for testing your zinc levels. Testing your zinc levels can be very important if you suspect a zinc deficiency or when you want to be sure your zinc is adequate.

One problem zinc testing has is that there are more than 25 zinc tests on the market today - some of which are very obscure. Below I've included the most commonly used zinc tests while telling you all about their validity.


Let's go...


Zinc Taste Test

First of all, let's consider the often used "zinc taste test".[256; 258; 263]

During the zinc taste test, you need a liquid zinc form. You need to combine two teaspoons of that liquid zinc with water and put the water into your mouth.

You next determine what taste the water has. One scenario is that you can only taste the water, for example. Alternatively, you may have an arid, mineral, or sugary taste. Another possibility is to have a somewhat or highly unpleasant reaction qua taste. 

The taste may also develop over time.

If you're getting the highly unpleasant reaction immediately, proponents of this zinc taste test argue that this implies you've got adequate zinc levels. If you're low on zinc instead, you might not taste much or nothing at all, or have a mildly unpleasant taste in your mouth.

The biggest problem with this test is that it's not accurate (and perhaps not even valid).

In other words:

Even though you might taste nothing, you can still have sufficient zinc levels. And even though you're having a strong unpleasant taste, you can still be zinc deficient.

There's more though: even if you don't taste anything other than water (which would indicate a zinc deficiency according to the zinc taste test), and supplement with zinc, you can still get the same outcome on the taste test again even though you're zinc sufficient now.

I consider the zinc taste test pretty useless because it leads to a lot of false positives and negatives.

Because this test is widely used, I decided to include it anyway here - as a critique.

So let's look at better options:

Secondly, there are "serum" and "plasma" tests for zinc in your blood - which I consider best currently.[256; 257; 270; 274; 278; 280; 282; 283; 284; 285; 295Both of these tests are high-quality.


Zinc Blood Plasma And Blood Serum Zinc Tests

Qua high-quality tests, let's consider the zinc blood plasma test first.[262; 340; 341; 342] 

Fortunately, the zinc blood plasma test does respond to changes in your zinc intake. If you increase your zinc intake through supplementation, for example, your plasma zinc levels will rise. If you quit supplementation for a few weeks, your zinc levels will drop again. 

That's what we're looking for...

The plasma blood test for zinc has thus very predictable changes to alterations in your zinc intake, through either food or supplementation. Fortunately, the validity of testing your zinc plasma levels has also been verified in multiple (independent) studies.

A problem that still exists with the blood plasma test is that zinc levels can change throughout the day. Fasting also affects the outcome of this test.[256

If you're really stressed, plasma zinc readings can be lower and the test is invalid as well. You thus have to make sure you're testing yourself on a day at which you're not taunted by your mother in law.

(I know that's easy for me to say as I'm single)

If you've got anaemia (i.e. low iron levels) or sepsis (blood infection) your blood plasma will also be lower - and the reading will be invalid.[343; 345Infections, problems with red blood cells or a previous heart infarction can skew the test - therefore making outcomes problematic.

The end result?

Zinc levels in the blood plasma can vary as much as 20% throughout the day. When measuring blood plasma, you thus need to correct for the time of the day your blood sample was taken.

The plasma zinc levels given below assume a morning fasted state while being non-stressed:

A good outcome of this test is to score above 80 micrograms per deciliter of blood. Under 76 micrograms per deciliter, you're highly deficient in zinc.

100-170 micrograms per deciliter seem to be optimal. I am for 130-140. Children are already deficient under 100 micrograms per deciliter - and thus need higher overall levels.

One more caveat: in general, women have somewhat lower zinc blood plasma levels than men.

Now, fortunately, there's another good option to test for your body's zinc status - although this option is not quite as good as the zinc blood plasma test:

Secondly, there's the blood serum zinc test.[344; 346; 347; 348; 349]

Levels in this test need to be between 70 micrograms per deciliter, and 120 micrograms per deciliter to avoid a deficiency - in children at least. A 100 micrograms reading is probably best again for children.

If you're older, 60 - 110 micrograms per deciliter are officially sufficient. I would recommend scoring at the higher outcomes in the range though, as a 60 - 80 micrograms per deciliter level might still put you in the "slightly deficient" territory. 

Remember that many people in modern society are slightly zinc deficient, even though they don't have a full-fledged dangerous zinc problem.

There's an extensive overlap between the blood serum and plasma tests:

If samples are taken and blood serum or plasma methods are processed at exactly the same time, with a same handling of the sample, no difference should be found in zinc concentrations in either method.[350; 351]

Lots of studies have actually been done verifying that the blood plasma and serum tests are the golden standards for zinc testing right now.

How do we know?

Zinc depletion studies reduce both zinc blood plasma and serum levels by 20-80% over a period of months.[295; 355; 356; 357; 358; 359; 360; 361; 362Just a few days of supplementation can already increase your zinc levels again.[287; 288; 363]

Intakes of 3 milligrams of zinc per day or less almost immediately lead to dangerous blood serum and plasma zinc levels. These zinc blood serum and plasma levels will only plateau around a zinc intake of 20 to 30 milligrams per day.[366]  

There's another upside to these tests though: both the plasma and serum zinc levels are also a good reflection of your zinc levels in other bodily tissues.[295]

In other words, if very little zinc can be found in your blood serum or plasma, you can expect your zinc levels to be depleted in your liver and bone as well. Vice versa, if your blood serum or plasma zinc levels are great the rest of your body necessarily has a good zinc status as well.


Urine Testing For Zinc Status

Thirdly, urine zinc levels can also give an above-average indication of your zinc levels.[272; 303; 372; 374; 375; 376 ]

There's a caveat to that conclusion though: if you're zinc-deficient you can excrete over 95% less zinc. Having very low zinc levels in your urine is thus not always a good indicator of overall health.

There does seem to be a relationship between zinc levels in your urine and serum, but I'd opt for the latter or a blood plasma zinc test to achieve the most accuracy.

A zinc urine test can help you diagnose what's happening with zinc in your body. Having below-average blood plasma zinc levels, combined with very high urine zinc levels, for example, tells you that you're excreting too much zinc.

The next step, in that instance, would be to find out why zinc is getting lost in your body...

We're not done yet though...

There's one more option:


Hair Mineral Analysis

Fourthly, a hair mineral analysis of zinc levels is also frequently used.[272; 367; 368; 369; 370; 371]

One problem with this hair mineral analysis test is that the outcome on the test does not always correlate very well with outcomes on a zinc blood serum test. As a consequence, the hair mineral analysis test is relatively useless compared to the "golden standard" of the zinc blood plasma and serum levels.

What's more, hair colour might even affect how much zinc can be found therein. Some diseases can even cause a decrease in hair and an increase in zinc serum levels - making the hair biomarker less useful. 

Overall, I would thus opt for the previously described options to test your zinc levels...



(Advanced Explanation: lastly, there are many other zinc tests of which the status is very currently unclear:

  • Salivary zinc - specifically saliva sediment - may be useful, but is not well-validated yet.
  • Red blood cell, and specifically metallothionein.[268; 269; 273; 279; 282; 284; 296] For nerds: erythrocyte metallothionein levels of zinc may deplete much quicker than serum plasma levels under zinc depletion - which is a sign that red blood cells more adequately reflect zinc cell levels. Nevertheless, only a few studies have been published on this method, and the measurement method is not standardized. Some studies also show that supplementation does not significantly alter red blood cell zinc levels.
  • White blood cell levels of zinc.[271; 275; 289; 297] White blood cell levels do not seem to increase with supplementation, while blood plasma levels do. Lymphocyte metallothinein levels may be a more sensitive method for testing zinc status than blood serum - although much more research is needed.[292]
  • Lymph system cells.[277There's very little data and standardization on this specific test.
  • Metallothionein gene expression - and erythrocyte and monocyte metallothionein.[287; 288] This is a prima facie interesting perspective but this method carries too little data as of right now.
  • Platelet zinc contents do not change with zinc supplementation.[289; 297That inability of zinc supplements to change the zinc content of platelets can be either good or bad.
  • Superoxide dismutase may be able to display zinc levels.[290; 291Superoxide dismutase zinc levels may even go down after supplementing with zinc, while serum zinc goes up.
  • 5'-nucleotidase enzyme may reflect very acute changes in zinc status, although more validation is needed.[293])

I included these tests to demonstrate that zinc testing can be a complex issue that's likely to develop over the next decade(s). Currently, these tests are not well validated enough, which is why I crowned the blood serum and plasma as the "golden standards".)

Bottom line: make sure to opt for the zinc blood plasma test whenever you can.

That's it...

Everything you need to know about zinc.

Let's therefore conclude, and take the 50,000-yard view:



Finishing Thoughts: Zinc Is Not Just An Afterthought.

But there is a simple solution...

There's one action that can take care of all your zinc needs once and for all:

oysters are the best solution to the problem described in this blog post

Eating a few dozen of oysters each week, however, is not affordable to everyone. For me, at this point, buying that many oysters are still expensive.

Yet, eating oysters is the best high-end option we have on this planet. 

Oysters clean ocean water, and produce food without needing any other foods to feed on (except plankton). 

So what's the solution if you're short on money?

Eat lots of high-quality red meat or eggs. Alternatively, consume some plant foods that are high in zinc but make sure to prepare them properly. Only in the worst-case scenario would I opt for supplementation. 

You need to get this right:

Zinc is a mineral that you cannot possibly ignore if your goal is optimal health. Zinc is important for just about any process in your body working properly:

  • Creating energy
  • Having your mind work well
  • Preventing diseases such as Alzheimer's and diabetes
  • Recovering from workouts and sleeping well
  • Looking good and feeling even better
  • Just kicking more ass

Unless you're eating loads of high-quality animal foods that are high in zinc, everyone should watch their zinc-deficiency symptoms.

And if you're not sure whether you're zinc deficient, do a zinc blood plasma or serum test.


Don't guess.

Don't assume.

Don't avoid a tough conclusion (or reality).

And if you absolutely cannot get sufficient zinc through your diet, make sure to buy a high-quality zinc supplement. 

Getting a year's worth of high-quality zinc supplements will cost you $50. That price is dirt-cheap.


Let's consider the example.

An example of sleep.

Assume that by supplementing with zinc, you're sleeping just 5% better during the night. I'm oversimplifying this calculation because zinc has many more benefits besides sleep that you already know of. For this example, let's also say you're earning just $10 per hour.

If you're sleeping 8 hours a night (equaling 480 minutes), you could save 24 minutes (5%) per night by taking a zinc supplement. On a yearly basis that's ~8,700 minutes, which equals ~140 hours.

Saving 140 hours on a yearly basis means making an additional $1,400 income. That's a massive gain for a $50 investment. And remember that in describing the scenario above, I've just included one specific zinc benefit. 

In reality, zinc may confer 5-15 unique benefits upon your life. In reality, you might be earning a lot more money than $10 per hour.

What's my point of this calculation?

Walking around with mineral deficiencies - such as zinc - is thus one of the most inefficient things you can do, for both your health, happiness, performance and getting the most out of your time in life.

An again, as promised, the fix is shockingly simple.

You can do it.

In fact, everyone can do it...



This is a post by Bart Wolbers. Bart finished degrees in Physical Therapy (B), Philosophy (BA and MA), Philosophy of Science and Technology (MS - Cum Laude), and Clinical Health Science (MS), and is currently a health consultant at Alexfergus.com. 


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