Should zinc bisglycinate be taken in the morning or at night?

Zinc Bisglycinate Timing: Morning vs Night

Zinc bisglycinate should be taken in the morning, 30 minutes before breakfast, on an empty stomach for optimal absorption. 1

Optimal Timing and Absorption

The evidence strongly supports fasting administration for zinc supplements:

• Take zinc 30 minutes before meals to maximize absorption, as food significantly interferes with zinc uptake through the intestinal transporters 1, 2
• Morning dosing before breakfast is the most practical fasting window for most patients, ensuring consistent adherence 1
• While zinc can be taken at night before bed (another fasting period), morning administration is preferred because it establishes a routine that patients are less likely to forget 2

Why Fasting Matters

The physiological basis for fasting administration is clear:

• Food components compete with zinc for absorption, particularly phytates, fiber, calcium, and other minerals that form insoluble complexes with zinc in the gastrointestinal tract 3
• When zinc supplements are taken with food, absorption can be reduced by approximately 15-20% compared to fasted administration 4
• The zinc bisglycinate formulation (also called zinc bis-glycinate) demonstrates 43% higher bioavailability compared to zinc gluconate, making it an excellent choice, but this advantage is still maximized when taken on an empty stomach 5

Practical Dosing Considerations

For standard supplementation doses:

• If taking less than 75 mg daily, a single morning dose 30 minutes before breakfast is sufficient 1
• If taking 75 mg or higher daily, split into at least two doses (morning and evening, both on empty stomach) to prevent transporter saturation 1
• The organic bisglycinate form has superior tolerability compared to inorganic zinc salts (like zinc sulfate), reducing gastrointestinal side effects even when taken fasting 6, 2

Common Pitfalls to Avoid

Several factors can compromise zinc absorption:

• Avoid coffee or tea within 1 hour of zinc administration, as these are powerful inhibitors of zinc absorption 6
• Do not take with calcium supplements or high-calcium foods, as calcium competes for the same absorption pathways 3
• If gastrointestinal upset occurs despite using bisglycinate, taking with a small amount of meat protein (not a full meal) can improve tolerance while maintaining reasonable absorption 6
• Monitor copper status if supplementing with 30 mg or more daily long-term, as zinc can induce copper deficiency at higher doses 2, 7

When Food Timing Is Less Critical

The only scenario where timing becomes less critical:

• If compliance with fasting requirements proves impossible, the bisglycinate form is more forgiving than other zinc salts and can be taken with food, though absorption will be reduced 2
• In this case, consider increasing the dose slightly to compensate for reduced absorption, but this should be discussed with a healthcare provider 1

Bottom line: Take zinc bisglycinate in the morning, 30 minutes before breakfast, with water only, for maximum benefit.