Zinc Bisglycinate
SupplementThe divergence of -10 points reflects that the clinical evidence specific to zinc bisglycinate is based on a small bioavailability study (n=12) [s1], whereas the community rating reflects broad positive user experience with good tolerability and subjectively perceptible effects [c1, c2]. The general zinc evidence base is robust, but form-specific RCTs are largely lacking.
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TL;DR
Zinc bisglycinate is the best-tolerated zinc form available — the chelate structure shields the mineral from phytates and other absorption inhibitors in the gut, boosting bioavailability by roughly 43% compared to zinc gluconate. Evidence for immune function, wound healing, and skin health is solid, though the medical score (50/100) reflects that many effects still lack large-scale RCT confirmation. Long-term users should monitor copper status: sustained doses above 25 mg elemental zinc per day can induce copper deficiency. Germany's BfR caps supplements at 6.5 mg elemental zinc daily — anyone targeting deficiency correction should confirm low levels with a blood test first.
Description
Chelated zinc form with +43% higher bioavailability than zinc gluconate; well tolerated; supports immune function, skin, hair, and wound healing [s1, s2].
Zinc bisglycinate is a chelated zinc compound in which one zinc atom is bound to two molecules of the amino acid glycine. This chelate structure protects zinc from dissociation by gastric acid and enables efficient absorption across the intestinal wall [s3, s4]. Compared to inorganic zinc forms such as zinc oxide or zinc sulfate, as well as to organic zinc gluconate, bisglycinate demonstrates significantly higher bioavailability: a human crossover study in 12 healthy women showed 43.4% higher oral bioavailability versus zinc gluconate [s1]. Zinc is an essential trace element involved in more than 300 enzymatic reactions [s5]. It supports immune function, promotes wound healing, protects cells from oxidative stress, and is important for skin, hair, and nail health [s5, s6]. Systematic reviews confirm that zinc supplementation can reduce the duration of colds and improve immune response [s6]. In acne vulgaris, meta-analyses show significantly lower zinc levels in affected individuals and improvement in inflammatory markers with oral zinc supplementation [s7]. A systematic review of eight clinical trials found that zinc deficiency lowers testosterone levels and that supplementation can restore them [s5]. Compared to other zinc forms, bisglycinate offers the advantage of fewer gastrointestinal side effects, as the chelate bond reduces the osmotic burden on the intestine [s2, s3]. It is particularly suitable for individuals with sensitive stomachs, vegans with elevated phytate intake, and older adults with reduced gastric acid production.
Legal Status (DE)
In the DACH countries, zinc bisglycinate is fully marketable as an over-the-counter food supplement (FS). The BfR recommends a maximum of 6.5 mg zinc per daily dose in food supplements [s9]. The EFSA sets the Tolerable Upper Intake Level (UL) for adults at 25 mg/day [s8].
Mechanism of Action
Zinc bisglycinate is absorbed in the small intestine (primarily duodenum and jejunum) via two mechanisms: actively through the zinc transporter ZIP4 (SLC39A4) at the brush border membrane, and passively at higher luminal concentrations [s3, s4]. The chelate structure of bisglycinate protects the zinc atom from forming insoluble complexes with phytates, oxalates, and tannins in the intestinal lumen—interactions that substantially reduce bioavailability of inorganic zinc forms [s1, s4]. At the cellular level, zinc acts as a cofactor for numerous metalloenzymes (e.g., superoxide dismutase, alkaline phosphatase, carbonic anhydrase) and as a structural component of zinc finger proteins involved in gene expression and signal transduction [s5]. In the immune system, zinc is required for T-lymphocyte maturation and natural killer cell function [s6]. In wound healing, zinc modulates both innate and adaptive immune responses and promotes collagen synthesis [s6]. In acne, zinc inhibits 5-alpha-reductase, the enzyme that converts testosterone to dihydrotestosterone (DHT), thereby reducing sebaceous gland activity and inflammatory responses [s7]. Regarding testosterone, data indicate that zinc is required for the hypothalamic-pituitary axis and testicular steroidogenesis [s5]. At chronically high zinc doses, zinc competes with copper for shared transport proteins (metallothioneins) in the intestinal epithelium, which can inhibit copper absorption and lead to secondary copper deficiency [s8, s10].
Dosing
Zinkversorgung und Immununterstützung (Allgemeinbevölkerung)
- Dose
- 7–15 mg elemental zinc
- Frequency
- 1× täglich
- Route
- oral
- Duration
- fortlaufend
- Timing
- Take with a meal
- With food
- empfohlen
Korrektur eines Zinkmangels (kurzfristig)
- Dose
- 15–25 mg elemental zinc
- Frequency
- 1× täglich
- Route
- oral
- Duration
- 4–8 Wochen
- Timing
- Take with a meal
- With food
- empfohlen
Aknebehandlung (adjuvant, unter ärztlicher Aufsicht)
- Dose
- 25–30 mg elemental zinc
- Frequency
- 1× täglich
- Route
- oral
- Duration
- 8–12 Wochen
- Timing
- Take with a meal
- With food
- empfohlen
The EFSA sets the Tolerable Upper Intake Level (UL) for adults at 25 mg zinc/day from all sources [s8]. The BfR recommends a maximum daily dose of 6.5 mg elemental zinc in food supplements [s9]. Doses above 40 mg/day may cause copper deficiency and anemia [s10].
Zinc bisglycinate contains approximately 20–25% elemental zinc by weight. A product providing 15 mg elemental zinc corresponds to approximately 60–75 mg zinc bisglycinate. Administration with a meal reduces gastrointestinal discomfort. Maintain a minimum interval of 2 hours from tetracyclines and quinolones [s10].
Side Effects
| Side Effect | Frequency | Severity |
|---|---|---|
| Übelkeit, Magenkrämpfe, Erbrechen Possible when taken on an empty stomach or at doses >25 mg. Bisglycinate is better tolerated than zinc oxide or zinc sulfate, but not entirely free of GI side effects [s1, s2, s3]. | gelegentlich | leicht |
| Metallischer Geschmack im Mund Classic zinc side effect, particularly reported at higher doses or intake without a meal [c1]. | gelegentlich | leicht |
| Kupfermangel (Anämie, Neutropenie, Immunschwäche) With chronic supplementation at doses >40 mg/day, zinc competes with copper for intestinal transporters (metallothioneins) and can lead to secondary copper deficiency with anemia and neutropenia [s8, s10]. | selten | moderat |
| Reaktion auf Glycin-Anteil (Verdauungsbeschwerden) A small proportion of users react specifically to the glycine component of bisglycinate with mild digestive complaints [c1]. | selten | leicht |
| Veränderung des LDL/HDL-Quotienten Long-term overdosage can adversely affect the lipid profile and increase the risk of atherosclerosis [s10]. | selten | moderat |
Contraindications
In pre-existing mineral regulation disorders, additional zinc supplementation may further disturb the zinc-copper balance [s8].
Impaired renal zinc excretion can lead to accumulation and toxicity with supplementation [s8].
Rare hypersensitivity reactions to the glycine component of the chelate compound are possible [c1].
Interactions
Synergistic
Vitamin C can support zinc absorption and acts synergistically in immune function and wound healing [s5].
For long-term zinc supplementation >15 mg/day, concurrent copper intake (1–2 mg/day) is recommended to prevent secondary copper deficiency [s8, s10].
Quercetin acts as a zinc ionophore and can transport zinc ions through cell membranes, improving intracellular zinc uptake. This combination is commonly recommended for immune function and antiviral effects.
Zinc and magnesium can be taken together at standard dosages without significant absorption interference. Both minerals together support immune function, enzyme activity, and sleep quality.
Caution
Zinc forms poorly absorbable chelate complexes with these antibiotics and significantly reduces their bioavailability. Maintain at least 2 hours between doses [s10].
Zinc and iron compete for shared absorption pathways (ZIP transporter) at high doses. Separate intake times recommended [s3].
Zinc can reduce the absorption of penicillamine (used for Wilson's disease or rheumatoid arthritis). Separate intake times required [s10].
High calcium doses can impair zinc absorption. Separate intake times (at least 2 hours apart) are recommended to avoid mutual absorption interference.
When supplementing zinc and GHK-Cu simultaneously, the zinc-copper ratio should be considered. Although the copper content in typical GHK-Cu doses (approx. 300 µg per 2 mg peptide) is low, high-dose zinc can further reduce copper availability.
Studies
Tier A — High Evidence
Outcome: Comparison of bioavailability of different zinc forms in humans
Effect Size: Bisglycinate more bioavailable than gluconate; picolinate showed highest absorption in one study
Outcome: Bioavailability of zinc bisglycinate vs. zinc gluconate (plasma zinc, erythrocyte zinc)
Effect Size: +43.4% higher oral bioavailability for bisglycinate (p<0.05)
Tier B — Moderate Evidence
Outcome: Effects of zinc on immune function, common cold duration, and wound healing
Effect Size: Significant reduction in common cold duration; improvement of immune markers in zinc deficiency
Outcome: Serum zinc levels in acne; efficacy of oral zinc supplementation
Effect Size: Significantly lower zinc levels in acne patients; improvement in inflammatory papulopustular score
Tier C — Low Evidence
Outcome: Bioaccessibility of different zinc forms in simulated intestinal environment
Effect Size: Differences in relative bioaccessibility depending on zinc form and pH conditions
Community Evidence
Top reported benefits
- Better gastric tolerability than zinc oxide or zinc sulfate
- Improved skin appearance and fewer blemishes
- Immune system strengthening (fewer colds)
- Improvement of hair quality and nail growth
- No or minimal nausea when taken with a meal
Top reported issues
- Metallic taste at higher doses
- Occasional nausea when taken on an empty stomach
- Price higher than other zinc forms
- Reactions to the glycine component in individual users
Some users discuss the risk of copper deficiency with long-term use without concurrent copper supplementation. Isolated reports of no perceived effect in individuals with already adequate zinc status. The community generally emphasizes checking for zinc deficiency before initiating supplementation.
Scientific Sources
- Zinc for prevention and treatment of the common cold
Nault D, Machingo TA, Shipper AG, Antiporta DA, Hamel C, Nourouzpour S, Konstantinidis M, Phillips E, Lipski EA, Wieland LS (2024). Cochrane Database of Systematic ReviewsAPMID:38719213DOI - Correlation between serum zinc and testosterone: A systematic review
Te L, Liu J, Ma J, Wang S (2023). Journal of Trace Elements in Medicine and BiologyBPMID:36577241DOI - A bioavailability study comparing two oral formulations containing zinc (Zn bis-glycinate vs. Zn gluconate) after a single administration to twelve healthy female volunteers
Gandia P, Bour D, Maurette JM, et al. (2007). International Journal for Vitamin and Nutrition ResearchAPMID:18271278DOI - Zink-Ergänzungspräparate – MSD Manual für Patienten / Überdosierungsrisiken und Kupfermangel
MSD Manual / Merck & Co. (2023). MSD Manual (Patientenversion, deutsche Ausgabe)BLink - Zinc for the treatment of the common cold: a systematic review and meta-analysis of randomized controlled trials
Singh M, Das RR (2012). CMAJCPMID:22566526DOI - Comparative Absorption and Bioavailability of Various Chemical Forms of Zinc in Humans: A Narrative Review
Ruz M, Carrasco F, Rojas P, et al. (2024). Nutrients (PMC)BLink - Comparison of the Potential Relative Bioaccessibility of Zinc Supplements—In Vitro Studies
Smolin Y, Grosicki M, Olędzki R, et al. (2023). Nutrients (PMC)CLink - Zink – Resorption, Transport und Verwertung im menschlichen Körper
DocMedicus Vitalstoff-Lexikon (Review) (2022). vitalstoff-lexikon.deBLink - Zinc: A Review of Clinical Use and Efficacy
NMI Health (Nutritional Medicine Institute Review) (2023). Nutritional Medicine Journal / NMI HealthBLink - Systematic review and meta-analysis of the effect of zinc on wound healing
Ye L, Wang H, Zhou X, et al. (2025). PMC / International Wound JournalALink - Serum zinc levels and efficacy of zinc treatment in acne vulgaris: A systematic review and meta-analysis
Yee BE, Richards P, Sui JY, et al. (2020). Dermatologic TherapyALink - Zinc Toxicity: Understanding the Limits
Maares M, Haase H, Rink L, et al. (2024). PMC / NutrientsBLink - Höchstmengenvorschläge für Zink in Nahrungsergänzungsmitteln – BfR Stellungnahme 006/2024
Bundesinstitut für Risikobewertung (BfR) (2024). BfR – Bundesinstitut für RisikobewertungALink
Community Sources
Storage
Unopened
Store in a dry place at room temperature, protected from direct sunlight and moisture.
Opened
Keep container tightly closed; avoid moisture ingress in powder or capsule forms.
Notes
Keep out of reach of children. Observe expiration date.