18–27 mg elemental iron daily, taken on an empty stomach with vitamin C (e.g., orange juice) for best absorption. Take in the morning, at least 4 hours away from any thyroid medication or calcium supplements.

15–30 mg daily with food to minimise nausea. Do not exceed 40 mg/day without medical supervision, as chronic high-dose zinc can cause copper deficiency and other problems.

2,500–5,000 mcg daily with a meal. Take consistently for at least 3–6 months — biotin works slowly but steadily.

5–10 g daily (typically 2.5–5 g per serve, taken once or twice daily). Mix into water, coffee, smoothies, or yoghurt — it dissolves easily. Timing is flexible; any time of day works.