Can you overdose on zinc supplements?
Taking food supplements can be a great way to ensure you’re getting enough of the essential nutrients your body needs, but it’s important to understand what ‘enough’ looks like.
The benefits of zinc, for example, are wide-ranging, as it supports the immune system, your vision and your overall wellbeing – but taking too much can trigger unwanted effects. To avoid this, understanding recommended dosages is key.
How many mg of zinc supplements should you take per day?
The amount of zinc you need each day depends on factors such as age, sex and overall diet. According to UK and European nutrition guidance, the recommended daily intake for adults is around 7 to 9.5 mg per day for women and 9.5 to 11 mg per day for men.¹
Many people already get zinc naturally from food. Common dietary sources include:
- Shellfish, especially oysters (15 mg of zinc per 90 g of oysters; 6 mg per 100 g of crab)
- Red meat and poultry (0.8 mg per 65 g of beef steak)
- Dairy products (1 mg per 240 ml of 1% milk)
- Whole grains (3 mg per 120 g of oats)
- Nuts, seeds and legumes (2 mg per 30 g of pumpkin seeds; 0.9 mg per 30 g of peanuts).8
Because zinc is found in so many everyday foods, people who eat a varied and balanced diet may already meet their daily needs without realising it.²
For most people, supplements are only needed as a convenient way to top up intake during times of increased demand, such as illness or periods of restricted eating.
How much zinc is too much?
While zinc is essential, it is possible to have too much. In the UK and EU, the safe upper limit for zinc from supplements is generally considered to be around 25 mg per day.³ This amount includes zinc from both supplements and your diet.
The important thing to remember is that you’re unlikely to overdose on zinc just by eating a healthy, balanced diet and taking a zinc supplement – even if oysters are on the menu.
Where there is a risk of overdose is if you consistently take more than 25 mg of zinc per day without the guidance of a medical professional.
What can happen if I take too much zinc?
Taking more zinc than your body needs, especially over a prolonged period, can interfere with how other nutrients are absorbed and used. Some effects may be mild at first, while others can develop over time and become more serious.
Possible effects of excessive zinc intake include:
- Digestive discomfort, such as nausea, stomach cramps or diarrhoea⁴
- Reduced copper absorption, which may lead to copper deficiency and affect iron levels⁵
- Changes in immune function, as very high zinc levels can disrupt the balance needed for normal immune responses⁶
- Lower levels of “good” HDL cholesterol when taken in high doses long-term.⁷
These effects highlight why more is not always the merrier when it comes to supplements. However, if zinc is taken correctly and in appropriate amounts, the risk of serious side effects remains low.
Is a zinc supplement necessary?
For many people, a healthy, balanced diet provides enough zinc without the need for supplements.² Oysters, in particular, contain very high levels of zinc, meaning frequent consumption can significantly increase intake.
However, supplements may be useful for some groups, including:
- People with restricted diets, such as vegans or vegetarians
- Individuals with digestive conditions that affect nutrient absorption
- Those advised by a healthcare professional following a confirmed deficiency.
It’s a good idea to consult a medical professional before taking zinc supplements. This is particularly important if you are already eating zinc-rich foods or are taking other supplements that may contain zinc.
A careful approach to zinc supplementation
While zinc is important for the normal functioning of the body, too much or too little can be detrimental. Knowing how much you need, where you can get it and how to avoid overdose is essential so you can reap the benefits without unwanted side effects.
If you have any worries or questions about zinc supplements, you can speak to a healthcare professional for advice tailored to your health needs.
References
- NHS. (2023). Vitamins and minerals – Zinc.
https://www.nhs.uk/conditions/vitamins-and-minerals/zinc/ - Harvard T.H. Chan School of Public Health. (n.d.). Zinc.
https://www.hsph.harvard.edu/nutritionsource/zinc/ - European Food Safety Authority. (2014). Scientific opinion on dietary reference values for zinc.
https://www.efsa.europa.eu/en/efsajournal/pub/3844 - Mayo Clinic. (2022). Zinc supplements: Benefits and side effects.
https://www.mayoclinic.org/drugs-supplements-zinc/art-20366112 - National Institutes of Health. (2023). Copper: Fact sheet for consumers.
https://ods.od.nih.gov/factsheets/Copper-Consumer/ - Linus Pauling Institute. (2022). Zinc and immune function.
https://lpi.oregonstate.edu/mic/minerals/zinc - Healthline. (2022). Zinc overdose: Symptoms and prevention.
https://www.healthline.com/health/zinc-overdose - Health Direct. (2025). Foods high in zinc. https://www.healthdirect.gov.au/foods-high-in-zinc