Zinc
Critical for immune function, testosterone and wound healing
What is Zinc?
Zinc is an essential trace mineral involved in over 300 enzymatic reactions and the structural integrity of more than 2,000 transcription factors. It's central to immune cell development and function, wound healing, DNA synthesis, protein synthesis, taste and smell sensation, and testosterone production. The body has no dedicated zinc storage — consistent daily intake is required to maintain status.
How it works
Zinc acts as a structural component of 'zinc finger' proteins — DNA-binding domains in transcription factors that regulate gene expression. It's essential for T-lymphocyte development (immune cells), thymulin production, and natural killer cell activity. In testosterone synthesis, zinc is a cofactor for 5-alpha reductase and inhibits aromatase (the enzyme that converts testosterone to oestrogen). It's also a structural component of insulin and insulin receptor signalling.
What the evidence shows
Immune: A 2011 Cochrane review found zinc lozenges started within 24 hours of cold onset reduced cold duration by ~1 day. A 2016 meta-analysis confirmed that zinc supplementation reduces acute lower respiratory infections in children. Testosterone: Multiple RCTs show that zinc supplementation in zinc-deficient men raises testosterone to normal levels. Skin/wound: RCTs show zinc sulphate improves wound healing, acne, and inflammatory skin conditions.
When to expect results
Immune function beginning to improve. Taste and smell may sharpen if these were blunted by deficiency.
Testosterone moving towards normal range in those who were deficient. Skin improving.
Full immune restoration. Wound healing rate improving. Acne reducing in inflammatory forms.
Sustained benefits across all zinc-dependent functions. Athletes notice reduced frequency of illness.
Dosing
Recommended daily intake: 9.5mg for men, 7mg for women (UK RNI). For therapeutic effects: 15–30mg elemental zinc. Avoid exceeding 40mg/day long-term — this can displace copper. If supplementing above 15mg daily, pair with 1–2mg copper to maintain balance. Zinc is best absorbed away from phytate-rich foods (wholegrains, legumes, nuts).
Forms to choose
Zinc bisglycinate: highest bioavailability, least GI discomfort. Zinc gluconate: commonly found in lozenges, well-absorbed. Zinc citrate: good absorption. Zinc picolinate: marketed as superior but evidence is mixed. Zinc oxide: poor absorption — avoid. Zinc sulphate: cheap and absorbed reasonably well but can cause nausea — take with food.
Who benefits most
Vegetarians and vegans (lower bioavailability from plant foods), athletes (zinc lost in sweat), older adults, people who get frequent colds or infections, men with testosterone at the low end of normal, anyone with acne or slow wound healing, people with digestive conditions reducing absorption (IBD, coeliac).
Who should avoid / caution
People taking copper supplements should ensure a balanced ratio. Those taking certain antibiotics (quinolones, tetracyclines) should separate zinc by 2 hours — it can reduce antibiotic absorption.
Interactions & stacking
High zinc competes with copper absorption. If supplementing 15mg+ daily long-term, add 1–2mg copper. The ideal zinc:copper ratio is 8:1.
High-dose zinc and magnesium compete. Separate by 2+ hours if both doses are elevated.
Together form a powerful immune-support combination. Vitamin C also enhances zinc absorption.
Phytates bind zinc and reduce absorption significantly. Take zinc away from high-phytate meals for best absorption.
Safety & side effects
At normal doses (up to 40mg): nausea, GI upset — take with food. Long-term above 40mg: copper deficiency (monitor with serum copper test), nausea, reduced immunity. Zinc nasal sprays caused permanent anosmia (smell loss) in some cases — avoid intranasal zinc. Excess zinc suppresses rather than enhances immunity above about 50mg/day.
Shop Zinc
Browse our UK-sourced, third-party tested zinc products.
Build your complete supplement stack
Our quiz tells you exactly which supplements to pair with this one
Find your perfect stack in 60 seconds — no email required.
This information is for educational purposes only and does not constitute medical advice. Always consult your GP or a qualified healthcare professional before starting any new supplement, particularly if you are pregnant, breastfeeding, have a medical condition, or are taking prescription medication.