Thorne · 60 capsules · $15.99
Zinc is an essential micronutrient that plays a key role in growth and development, immune function, and testosterone metabolism, along with numerous other functions in the body. It is the second-most abundant mineral in the body, after iron.
Clinical studies demonstrate zinc supplementation can increase general wellness and has a beneficial impact on connective tissue, reproductive, and eye health.* Zinc Bisglycinate is absorbed intact and does not compete with other minerals for absorption in the intestinal tract.
A cross-over study demonstrated supplementation with zinc in the bisglycinate form resulted in 43% higher zinc blood levels compared to zinc gluconate.
Zinc Bisglycinate is zinc bound to two molecules of the amino acid glycine, a calming neurotransmitter that supports relaxation and promotes the body’s production of glutathione, an important antioxidant and cofactor in detoxification and immune functions.*
Benefits of Thorne’s Zinc Bisglycinate 15 mg
Who may benefit from Thorne’s Zinc Bisglycinate 15 mg
Features of Thorne’s Zinc Bisglycinate
This product has been third-party tested and certified to verify what's in the package matches what's on the label and to confirm it contains no unsafe levels of contaminants, such as heavy metals, pesticides, and microorganisms.
Zinc (as zinc bisglycinate) ... 15 mg
Zinc bisglycinate is a supplemental form of zinc in which the mineral is bound to two molecules of the amino acid glycine. That chelation is intended to improve absorption and reduce stomach upset compared with some salts. It supplies the same elemental zinc the body uses, and amounts belong on the label and with a clinician.
This page explains what the form is, how it compares with other common forms, what the published research has and has not shown, which interactions are worth asking a pharmacist about, and how zinc status is actually measured rather than assumed.
Chelation means the zinc ion is held inside an organic molecule rather than paired with a simple salt partner. In bisglycinate, two glycine molecules wrap around one zinc ion, forming a stable, low charge complex. The idea is that the complex survives more of the digestive journey intact, so less zinc is released as a free ion that can bind to dietary compounds before it reaches the absorptive surface of the small intestine.
That matters because free zinc ions are chemically sociable. Phytate from whole grains and legumes, calcium, and other divalent minerals can all bind zinc in the gut lumen and reduce how much crosses into the bloodstream. Zinc shares transport machinery and regulatory pathways with iron and copper, and absorption of all three is tightly controlled rather than simply proportional to intake 2.
Research suggests that the chemical form of zinc influences how much is absorbed, although the differences between the better absorbed forms are modest rather than dramatic 1. The practical reading is that bisglycinate is a reasonable, generally well tolerated choice, not a different nutrient.
Related: Foods Containing Zinc, Vegetarian Sources That Absorb
The forms differ in what zinc is bound to, how much elemental zinc the compound carries by weight, and how gently they tend to sit in the stomach. Head to head human absorption data remains limited, so treat the comparison below as general characteristics rather than a ranking.
| Form | What it is | What is generally noted |
|---|---|---|
| Zinc bisglycinate | Zinc chelated to two glycine molecules | An amino acid chelate, often chosen for gastrointestinal tolerability; absorption is generally reported as comparable to or better than simple salts |
| Zinc picolinate | Zinc bound to picolinic acid | Another chelated form with a long history of use; direct comparative human data against other chelates is sparse |
| Zinc gluconate | Zinc salt of gluconic acid | Widely used and inexpensive; a familiar form in lozenges and general supplements |
| Zinc sulfate | Inorganic zinc salt | The form used in much of the older clinical and fortification literature; more commonly associated with stomach upset at higher intakes |
| Zinc oxide | Inorganic oxide | Low solubility; frequently used in fortification and topical products rather than chosen for absorption |
Elemental zinc content varies by compound, which is why two products with the same milligram figure on the front of the bottle can deliver different amounts of the mineral. The label states the elemental amount, and how much of it is appropriate for any individual is a question for the label and a clinician, not for an article.
Zinc is an essential trace mineral that acts as a structural and catalytic component of hundreds of enzymes and of the zinc finger proteins that help regulate gene expression. It is involved in immune cell function, protein synthesis, wound repair, taste perception, skin integrity and normal growth and development.
Because the body has no large storage depot for zinc, status depends on a continuing balance between intake, absorption and losses. Severe zinc deficiency is associated with impaired growth, characteristic skin lesions, diarrhoea, impaired wound healing and impaired immune function, and milder deficiency is harder to recognise because its features are non specific 3. Diets high in phytate and low in animal protein, malabsorptive gut conditions and increased losses are among the recognised contributors to low status 3.
Three questions matter most for zinc: how different chemical forms are absorbed, what happens when deficiency is corrected, and what happens at the high end of intake.
On absorption, narrative review work has compared inorganic salts, organic salts and amino acid chelates, and research suggests that organic and chelated forms are at least as well absorbed as inorganic salts, with the caveat that study designs, tracer methods and background diets differ enough to make firm rankings difficult 1. Absorption also rises when status is low and falls when intake is high, which is a homeostatic feature of zinc handling rather than a quirk of any one product 2.
On population level correction, zinc fortification of staple foods has been studied extensively as a public health strategy 5. A systematic review of fortification trials found that zinc fortification may increase total zinc intake and, in some settings, serum zinc concentrations, while evidence for consistent effects on functional outcomes such as growth or infection was weaker 6.
On the upper end, reviews of zinc toxicity describe what is seen with excessive intake, including gastrointestinal symptoms with acute excess and interference with copper status over longer exposure 4.
It does not show that zinc bisglycinate, or any zinc supplement, treats a disease. Nothing in the cited literature supports marketing a zinc product as a therapy for infection, fertility, mood, skin disease or anything else, and this page makes no such claim.
It also does not show that correcting a deficiency and supplementing someone who already has adequate status produce the same result. Correcting a genuine shortfall is not the same as benefit in people whose intake and status are already sufficient. Because absorption is down regulated as intake rises, more is not reliably more 2.
Finally, the comparative absorption literature does not establish that one chelated form is clinically superior to another for health outcomes. Better absorption in a laboratory measure is not the same as a better result in a person.
The most commonly reported effects are gastrointestinal: nausea, stomach discomfort, vomiting, a metallic taste, and occasionally diarrhoea. Nausea is the complaint that sends most people looking for a gentler form in the first place, and reviews of zinc excess describe gastrointestinal upset as a characteristic feature of intakes that are too high 4.
Amino acid chelates such as bisglycinate are frequently chosen because they are reported to be gentler than some salts, but tolerability is individual and no form is exempt. If a supplement consistently causes nausea, that is worth raising with a clinician or pharmacist rather than pushing through, and the amount and timing printed on the label are the reference point.
Sustained high intake is a separate issue from an upset stomach. Chronic excess has been linked with copper depletion and, through that route, with haematological and neurological problems, which is why upper intake limits exist at all 4. A reaction that feels severe, or any new unexplained symptom while supplementing, is worth discussing with a clinician promptly.
Zinc and copper compete. High zinc intake induces metallothionein in intestinal cells, a binding protein that holds copper inside the enterocyte so that it is shed with the cell rather than absorbed. Over time, that mechanism can lower copper status, and the interaction between zinc, copper and iron absorption is a well described feature of trace mineral handling.
Excess zinc intake is associated with reduced copper status over prolonged exposure, which is the main reason sustained, unsupervised high intake is discouraged 4. Copper deficiency is not something a person feels arriving. It can present with anaemia that does not respond to iron, low white cell counts or neurological symptoms, all of which have many other possible explanations.
The practical implication is simple. Long running zinc supplementation is a reason to check copper and zinc together on bloodwork rather than to assume balance is being maintained, and the decision about how long to continue belongs with a clinician who can see those results.
Several medicines and minerals can interact with zinc in both directions. These are described so that you can raise them with a clinician or pharmacist, not so that you can adjust anything yourself. Never stop or change a prescribed medicine on the basis of a web page.
Anyone taking prescription medication, and anyone in one of the situations below, should have the conversation before adding a zinc supplement rather than after.
The usual starting point is a serum or plasma zinc test, which measures circulating zinc at a single moment. It is the most widely available marker, and it has real limitations: zinc falls during inflammation and acute illness, varies with time of day and fasting state, and can be affected by recent supplement intake, so a single value is interpreted alongside context rather than read alone.
| Marker | Typical lab reference range | Unit |
|---|---|---|
| Serum or plasma zinc | approximately 60 to 120 | µg/dL |
These are typical laboratory reference ranges. Ranges vary by lab, assay, age and sex, and your own report's range is the one that applies.
Read a result the same way a clinician would. The observation is where the number sits within the lab's range. The meaning is hedged, because a low value may reflect genuinely low intake or absorption, or it may reflect inflammation, recent illness or sample handling, and a high value may reflect recent supplementation. The next step is a conversation: a value outside the standard range, or a suboptimal value in someone with ongoing symptoms, is worth discussing with a clinician who can look at inflammatory markers, copper, iron studies and the rest of the picture together. FitScript tests zinc as part of a membership built around 150+ biomarkers tested per year, with results interpreted by Atlas, the AI health advisor, alongside the rest of a member's bloodwork.
This article is educational and is not medical advice. Discuss your results, your supplements and any treatment decisions with a clinician or licensed provider who can review your full history.
To see what the test measures, how it behaves and why it is read alongside other markers, visit the Zinc biomarker page.
It is zinc bound to two molecules of the amino acid glycine, a structure known as an amino acid chelate. The chelation is intended to keep the zinc stable through digestion and to make it gentler on the stomach than some simple zinc salts. The mineral delivered is the same elemental zinc the body uses in enzymes and immune cells.
Chemical form may influence zinc absorption, with chelated and organic forms generally absorbed at least as well as inorganic salts, but how chelates compare with each other is not settled. It is not established that one chelated form produces better health outcomes than another, so tolerability and what your clinician advises matter more than the ranking.
That is not something an article can answer. Amounts, units and timing belong on the product label and in a conversation with a clinician or pharmacist who knows your diet, your medications and your current zinc status. Requirements differ by age, sex, pregnancy status and absorption, and intake from fortified foods and multivitamins counts toward the total.
Zinc can irritate the gastric lining, and nausea, stomach discomfort, vomiting and a metallic taste are the most commonly reported effects. Reviews of zinc excess describe gastrointestinal upset as a characteristic feature of intakes that are too high. Chelated forms are often chosen because they are reported to be gentler, but tolerability varies between individuals and persistent nausea is worth raising with a clinician.
It can. High zinc intake increases a binding protein in intestinal cells that traps copper and reduces how much is absorbed, and excess zinc intake is associated with reduced copper status over prolonged exposure. Copper deficiency can show up as anaemia that does not respond to iron, low white cell counts or neurological symptoms, which is why long running supplementation is a reason to have both minerals measured.
Serum or plasma zinc is the most widely available test and typically falls in a reference range of roughly 60 to 120 µg/dL, though ranges vary by laboratory, assay, age and sex. It is a snapshot: levels drop during inflammation and acute illness and shift with time of day, fasting and recent supplement intake, so results are interpreted alongside inflammatory markers and the wider picture.
Anyone taking prescription medication, anyone who is pregnant or breastfeeding, people with reduced kidney function, people with malabsorptive gut conditions or a history of bariatric surgery, anyone with anaemia or known low copper, and anyone already taking a multivitamin or several fortified products. Children and adolescents have different requirements and should be assessed individually.
Benefit in that situation is not established. Correcting a genuine shortfall is not the same as benefit in someone already replete. Zinc absorption is down regulated as intake rises, so taking more does not reliably achieve more, and sustained high intake carries its own copper related trade off.