ADHD and Multivitamins: What the Broad-Spectrum Vitamin and Mineral Trials Found and Where They Fall Short

What these products are

ADHD and multivitamins get talked about because of one specific type of product, not the cheap one-a-day tablet in the supermarket. Researchers call them broad-spectrum micronutrients or multinutrients: formulas that pack in most known vitamins and essential minerals at once.

The idea is that the brain relies on lots of nutrients working together, so giving them all at once might do more than testing one at a time. The main ADHD trials come from research teams in New Zealand, the US and Canada.

Why people try them

If you've already looked at magnesium, zinc, iron or vitamin D on their own, a single product that covers the lot sounds easier. It's one decision instead of five, and it feels like a safer bet than guessing which nutrient you might be short of. That's the appeal. Whether it works is a separate question, and the trials so far give a mixed answer.

The adult trial

A 2014 trial in the British Journal of Psychiatry, by Rucklidge and colleagues, gave 80 adults with ADHD either a vitamin and mineral formula or a dummy pill for eight weeks. On the participants' own ratings and observer ratings, ADHD symptoms improved more with the formula than with the dummy pill.

The clinicians' ADHD rating scale didn't show a difference, although clinicians did rate the formula group as more improved, both overall and on ADHD symptoms. There were no differences in side effects between the groups. The authors called it preliminary evidence, and it's still the main trial we found in adults.

The children's trials

A 2018 trial by the same team, in the Journal of Child Psychology and Psychiatry, included 93 children aged 7 to 12 who weren't taking ADHD medication. After ten weeks, 47% on the formula were rated "much" or "very much" improved by clinicians, compared with 28% on the dummy pill. But there was no difference on overall ADHD symptom ratings from clinicians, parents or teachers, and no improvement in hyperactive or impulsive symptoms. The bigger changes were in emotional regulation, aggression and general day-to-day functioning.

The largest trial so far, known as the MADDY study, was published in 2022. It included 126 children aged 6 to 12 with ADHD and irritability, again not taking medication. Clinicians rated 54% of the formula group as responders, compared with 18% on the dummy pill. Parents' ratings improved in both groups by roughly the same amount, so on that measure the formula was no better than a placebo. The formula group also grew 6mm more in height over the eight weeks, and there were no serious side effects.

What reviews say

A 2020 review in Nutrients, by Johnstone and colleagues, pooled the ADHD trials and found improvements in clinician ratings of overall functioning and global improvement, and in clinician measures of inattention, but not in observer ratings of inattention. It also found that broad formulas did better than ones with only a few ingredients.

Three of the review's authors had worked on the trials it included, which they declared, and they said more well-run, fully reported trials are needed. The pattern across all of this is the same: clinicians tend to see a difference, but the core ADHD symptom scores, especially from parents, often don't move much more than with a dummy pill.

Not your usual multivitamin

The MADDY formula was nine to 12 capsules a day, taken in three doses, with amounts above the recommended daily allowance but below the upper safe limits. The maker, Hardy Nutritionals, supplied it free for the trial. That's very different from a single high-street multivitamin, so the results can't be applied to whatever's in your cupboard.

Remembering to take capsules three times a day is its own challenge with ADHD too, and none of these trials tell you what happens over months or years.

Safety and medication

The NICE guideline on ADHD doesn't recommend vitamin and mineral formulas as a treatment, and its dietary advice focuses on a balanced diet, good nutrition and regular exercise. The NHS says most people should get the nutrients they need from a varied and balanced diet, although some people may need extra supplements. More isn't automatically better either. NHS guidance warns that many multivitamins contain vitamin A, which can affect your bones over many years if you have too much, and that iron doses over 20mg can cause stomach problems.

The children's trials only included children who weren't taking ADHD medication, so they don't tell you anything about combining these formulas with prescribed treatment. The NHS says to tell your doctor or pharmacist if you're taking other medicines, including vitamins or supplements, and the trials don't support swapping prescribed treatment for a supplement.