ADHD and Zinc: What the Studies Show, Where They Fall Short and How to Take It Safely

Why zinc comes up

ADHD and zinc get mentioned together because a handful of studies, mostly in children, found lower zinc levels in some kids with ADHD, and a few trials suggested zinc might help a bit. So you end up in the chemist holding a cheap tub of zinc tablets, wondering if it's worth a go. The evidence is thin, and almost none of it involves adults.

What zinc does

Zinc is a mineral your body uses to make new cells and enzymes, process carbohydrate, fat and protein from food, and heal wounds. According to the NHS guide to zinc and other minerals, men aged 19 to 64 need about 9.5mg a day and women need about 7mg. Meat, shellfish, cheese, bread and cereal products like wheatgerm are all good sources, and the NHS says most people should get all they need from a varied diet.

What studies found

The research is a mix of blood and hair tests comparing people with and without ADHD, and a small number of trials giving zinc to children. Here's what the main ones actually show.

Lower zinc in some children

A 2021 review of 22 studies covering 1,280 people with ADHD and 1,200 without found no clear overall difference in blood or hair zinc. When one study was left out, people with ADHD did come out lower on average. Other reviews, including one of 17 studies in Chinese children, have found lower levels in children with ADHD. That points to a possible link, not proof that low zinc causes ADHD.

Zinc alongside medication

A 2004 trial in Iran gave 44 children aged 5 to 11 methylphenidate plus either zinc or a dummy pill for six weeks. The zinc dose was about 15mg a day. Parent and teacher ratings improved more in the zinc group. It was small and short, and the researchers said it needed repeating with different doses.

Zinc on its own

A 2004 trial in Turkey gave 400 children either zinc or a dummy pill for 12 weeks. Zinc did better on hyperactivity, impulsivity and social skills, but not on attention problems. Only 28.7% of the zinc group had a full response, compared with 20% on the dummy pill, so most children didn't see a big change.

A trial in the US

A 2011 American trial gave 52 children aged 6 to 14 zinc or a dummy pill for eight weeks, then added amphetamine, an ADHD medicine, for five more. The results on ADHD symptoms were mixed, sometimes favouring zinc and sometimes the dummy pill. The small group on 30mg of zinc a day ended up on a lower amphetamine dose, but that was a closely monitored research study, not something to copy at home.

Putting it together

A 2021 review pooled six trials covering 489 school-age children. Zinc gave a small improvement in overall ADHD scores, but not in hyperactivity or inattention when they were looked at separately, and the certainty of the evidence was rated moderate to very low. There don't appear to be any proper trials of zinc for ADHD in adults, so claims that it helps grown-ups focus are unproven.

Taking zinc safely

The NHS says not to take more than 25mg of zinc supplements a day unless a doctor advises it. High doses reduce how much copper you absorb, which can lead to anaemia and weaker bones. Zinc often turns up in more than one product, so check the back of your multivitamin, immune blend and any "focus" supplement. Add up the zinc figures and save the total in a phone note, so you can see if you're doubling up.

Medicines it affects

Zinc can affect how some antibiotics work. The NHS lists supplements containing zinc among the things that don't mix well with doxycycline and lymecycline, two antibiotics used for acne and a range of infections. If you're given an antibiotic, tell the pharmacist about every supplement you take, and follow the leaflet's advice on spacing them out. If you take ADHD medicine, tell your prescriber before adding zinc, and never change your medicine dose because of a supplement.

Before you try

Zinc isn't one of the treatments in the NICE guideline on ADHD, and there's no good evidence it helps adults who already get enough from food. If you think your diet might be low in zinc, ask a GP rather than guessing. A pharmacist can check whether a supplement is safe alongside anything else you take. If you do decide to try it, stick within the NHS limit and keep taking any prescribed treatment as normal.