Zinc is the second most abundant trace element in the human body after iron, playing a vital role in immune support, wound healing, and sensory perception. When dietary intake falls short, supplements become necessary. Two popular, highly bioavailable forms are zinc bisglycinate and zinc picolinate. This guide will help you determine which is better suited for your needs.
Understanding the Forms
Both zinc bisglycinate and zinc picolinate are chelated forms of zinc, meaning the mineral is bound to another molecule to enhance absorption. This chelation process helps the zinc pass through the digestive tract more efficiently.
- Zinc Bisglycinate: In this form, a single zinc ion is bound to two molecules of the amino acid glycine. This creates a stable compound that can be transported through specialized peptide channels in the intestine, which are typically used for protein absorption, minimizing interference with other minerals.
- Zinc Picolinate: Here, zinc is bound to picolinic acid, a natural substance synthesized in the body from the amino acid tryptophan. Picolinic acid acts as a carrier, helping cells absorb the mineral more easily.
Bioavailability and Absorption Comparison
Multiple studies have explored the absorption rates of various zinc forms. Research suggests that organic forms of zinc are better absorbed than inorganic compounds like zinc oxide or sulfate.
A study involving 12 healthy women compared single doses of zinc bisglycinate, zinc picolinate, zinc gluconate, and zinc oxide. Over a four-hour period, zinc bisglycinate resulted in the highest plasma and red blood cell zinc levels, followed by picolinate. Other research found that zinc bisglycinate was absorbed 43.4% better than zinc gluconate.
While zinc bisglycinate shows a slight edge in some short-term studies, zinc picolinate is also widely recognized as a well-absorbed and effective form. The key takeaway is that both are excellent choices compared to less bioavailable options.
Tolerability and Side Effects
One of the most common complaints with zinc supplementation is gastrointestinal upset, especially on an empty stomach. Zinc bisglycinate is often highlighted for its superior tolerability and gentler nature on the stomach compared to other forms. Its chelated structure helps reduce the likelihood of nausea, stomach cramps, or diarrhea.
Zinc picolinate is generally well-tolerated, but some individuals might experience more side effects than with the bisglycinate form. Both forms, when taken in high doses (above the Tolerable Upper Intake Level of 40 mg of elemental zinc per day), can lead to adverse effects, including copper deficiency over time.
Feature Comparison Table
| Feature | Zinc Bisglycinate | Zinc Picolinate |
|---|---|---|
| Chelating Agent | Glycine (amino acid) | Picolinic acid |
| Absorption Rate | Very high; generally considered superior in studies | High; a very effective, well-absorbed form |
| Stomach Tolerability | Excellent; very gentle on the digestive system | Good; generally well-tolerated |
| Interference with other minerals | Minimal interference with other mineral absorption | Less potential for interference than some forms, but a consideration at high doses |
| Common Use | General health, immune support, gentle supplementation | Immune support, skin health (acne), addressing deficiencies |
Conclusion: Making the Right Choice
Both zinc bisglycinate and zinc picolinate are excellent choices for raising zinc levels in the body due to their high bioavailability. Zinc bisglycinate is generally considered the top contender for its slight edge in absorption studies and its exceptional gentleness on the stomach, making it ideal for individuals with a sensitive digestive system. Zinc picolinate is a powerful, highly absorbable option with a long history of use in clinical studies, particularly effective for targeted goals like skin health. The best form ultimately depends on individual tolerance and health goals. Always adhere to recommended dosages and consult a healthcare professional before starting any new supplement regimen.
Key Research & Further Reading
For those interested in the specifics of zinc absorption, a key study compared the bioavailability of several forms. You can review an abstract of one such study here: A Bioavailability Study Comparing Two Oral Formulations.
