If you have ADHD, you have probably come across claims that certain vitamins, minerals, herbs or “nootropics” can improve concentration, increase dopamine, reduce impulsivity or even replace ADHD medication.
Supplements such as omega-3, magnesium, zinc, iron, vitamin D, ashwagandha and Lion’s Mane are frequently discussed online. Others, including caffeine, 5-HTP, GABA and various herbal preparations, are promoted as natural ways of improving focus or regulating the nervous system.
But how much of this is supported by evidence?
The answer is more nuanced than either “supplements don't work” or “ADHD can be treated naturally”.
Some supplements may have a role in particular circumstances. However, there is currently no nutritional supplement with evidence comparable to established ADHD treatments, and many products marketed specifically for ADHD have been inadequately studied.
Omega-3 fatty acids
Of the nutritional supplements studied in ADHD, omega-3 fatty acids are probably the best researched.
Omega-3 fatty acids, particularly EPA and DHA, are involved in neuronal membranes and normal brain function. Several studies have investigated whether supplementation can reduce ADHD symptoms.
Some meta-analyses have found small improvements in attention and other ADHD symptoms, particularly with formulations containing EPA. However, findings across studies have been inconsistent, and when benefits are seen their magnitude is generally much smaller than that associated with established ADHD medication.
For someone who does not eat much oily fish or whose diet contains relatively little omega-3, supplementation may therefore be reasonable to discuss as part of a broader treatment plan.
I would consider omega-3 an adjunct rather than a treatment for ADHD in itself.
Iron:
Iron is particularly interesting because of its involvement in dopamine synthesis and brain function.
Research has found an association between low iron stores and ADHD in some populations, although association does not automatically mean that iron deficiency causes ADHD.
There is some evidence—predominantly in children—that iron supplementation may improve symptoms when iron stores are low. This makes identifying and treating genuine iron deficiency clinically important.
What I would not recommend is taking iron routinely simply because someone has ADHD.
Excess iron can be harmful. If iron deficiency is suspected, it is preferable to assess this appropriately, usually including ferritin alongside the wider clinical picture, and supplement when there is an indication to do so.
Zinc, magnesium and vitamin D:
Zinc, magnesium and vitamin D are also frequently promoted for ADHD.
There are biological reasons why deficiencies in these nutrients could affect cognition, energy, sleep or general psychological wellbeing. Some studies have also reported differences in micronutrient status in people with ADHD.
However, the evidence that routinely supplementing zinc, magnesium or vitamin D directly treats ADHD symptoms in people who are not deficient remains limited and inconsistent. Reviews of nutritional interventions have therefore not supported routinely prescribing these micronutrients as stand-alone ADHD treatments.
The distinction is important:
Correcting a deficiency is not the same as treating ADHD with a supplement.
If someone is deficient in iron, vitamin D or another nutrient, treating that deficiency may improve fatigue, cognition, sleep or general wellbeing. Those improvements can make managing ADHD easier, even if the nutrient itself is not treating the underlying neurodevelopmental condition.
Caffeine:
Many adults with ADHD describe using substantial amounts of coffee, energy drinks or other sources of caffeine to concentrate.
This makes intuitive sense: caffeine is a stimulant and can temporarily increase alertness. However, caffeine is not equivalent to ADHD medication, and increasing the dose can create additional problems. High caffeine intake can interfere with sleep and may contribute to jitteriness, palpitations or anxiety in susceptible people. A systematic review of caffeine and sleep found reductions in total sleep time and sleep efficiency following caffeine consumption.
This can become counterproductive in ADHD because inadequate sleep itself can worsen attention, executive functioning and emotional regulation.
Particular caution is sensible when combining large amounts of caffeine with prescribed stimulant medication.
5-HTP and L-tryptophan:
Supplements such as 5-HTP and L-tryptophan are sometimes marketed for mood, sleep and emotional regulation.
There is not convincing evidence that either is an effective treatment for ADHD.
They are also not pharmacologically inert. Both relate to serotonin synthesis, which means they can potentially interact with medicines that affect serotonin, including some antidepressants. L-tryptophan in combination with serotonergic medicines can, in some circumstances, contribute to potentially serious serotonin toxicity.
This is particularly relevant because anxiety and depression commonly coexist with ADHD, meaning many people considering these supplements may already be taking serotonergic medication.
GABA supplements:
GABA is the brain's main inhibitory neurotransmitter, so supplements containing GABA are often marketed as promoting calmness or reducing anxiety.
Unfortunately, the marketing tends to run ahead of the clinical evidence.
There is currently insufficient good-quality evidence to recommend oral GABA supplementation as a treatment for ADHD. Products marketed as “calming the nervous system” should therefore not automatically be assumed to correct a specific neurochemical abnormality in ADHD.
Ashwagandha, Lion's Mane and medicinal mushrooms:
Ashwagandha and medicinal mushrooms such as Lion's Mane, Reishi and Cordyceps have become increasingly popular in products marketed for concentration, stress and cognitive performance.
There is some preliminary research into ashwagandha for stress, sleep and aspects of cognition, and small studies of Lion's Mane have investigated cognitive performance in people without ADHD. This is very different from demonstrating that these products treat ADHD.
At present, there is not enough high-quality ADHD-specific evidence for me to recommend them as established ADHD treatments.
Ashwagandha also deserves caution because herbal does not mean biologically inactive. It can interact with medicines and has particular considerations in people with thyroid or autoimmune conditions, as well as rare reports of liver injury.
Valerian and kava:
Valerian is commonly included in products marketed for relaxation and sleep. Evidence for its effectiveness in chronic insomnia is inconsistent, and it should not be considered an ADHD treatment.
Kava raises greater safety concerns. Although it has been studied for anxiety, kava-containing products have been associated with rare cases of serious liver injury.
St John's wort:
St John's wort is another good example of why the word “natural” can be misleading.
A placebo-controlled trial examining St John's wort specifically for ADHD found no significant improvement in ADHD symptoms.
More importantly, St John's wort can interact with a large number of medicines by altering how the body metabolises them. These interactions can reduce the effectiveness of some medications or increase the risk of adverse effects.
It is therefore something I would be particularly cautious about taking without discussing it with a doctor or pharmacist.
Supplements are not automatically harmless!
One of the most common misconceptions around supplements is:
“It is natural, so it can't do any harm.”
Natural substances can still alter neurotransmitters, liver enzymes, blood pressure, thyroid function, sedation and the metabolism of prescription medicines.
The risk becomes particularly relevant when several supplements are combined, when high doses are taken, or when supplements are used alongside medications such as stimulants, antidepressants, sedatives, anticonvulsants or other psychiatric medication.
Supplement quality can also vary considerably between manufacturers.
So, should someone with ADHD take supplements?
Rather than asking “What supplements should everyone with ADHD take?”, I think a more clinically useful question is:
“Is there something specific in this person's diet, health or blood results that needs addressing?”
For example, it may be reasonable to consider whether somebody has iron deficiency, vitamin D deficiency, a restricted diet, inadequate omega-3 intake or another nutritional problem.
That is very different from assuming that every person with ADHD requires the same collection of supplements.
For some people, omega-3 may be a reasonable adjunct. Correcting genuine nutritional deficiencies is important. Melatonin may sometimes have a role when sleep is the problem.
But supplements should not be presented as a substitute for a proper ADHD assessment or for evidence-based treatment when treatment is needed.
ADHD is complex, and good care usually means looking beyond a single tablet—whether that tablet comes from a pharmacy or from a supplement shop.
This article is for general information and does not constitute individual medical advice. Supplements can cause adverse effects and interact with prescription medicines. If you are taking medication, are pregnant or breastfeeding, or have an underlying medical condition, discuss supplements with an appropriately qualified healthcare professional.
Thanks for reading!
References:
- Bloch MH, Qawasmi A. Omega-3 fatty acid supplementation for the treatment of children with attention-deficit/hyperactivity disorder symptomatology: systematic review and meta-analysis. Journal of the American Academy of Child & Adolescent Psychiatry. 2011;50(10):991–1000.
- Lange KW, Lange KM, Nakamura Y, Reissmann A. Nutrition in the management of ADHD: a review of recent research. Current Nutrition Reports. 2023;12(3):383–394. doi:10.1007/s13668-023-00487-8.
- McWilliams S, Singh I, Leung W, Stockler S, Ipsiroglu OS. Iron deficiency and common neurodevelopmental disorders—a scoping review. PLoS One. 2022;17(9):e0273819. doi:10.1371/journal.pone.0273819. The review found that the evidence linking iron deficiency and supplementation with ADHD outcomes comes predominantly from paediatric studies.
- van der Heijden KB, Smits MG, van Someren EJW, Ridderinkhof KR, Gunning WB. Effect of melatonin on sleep, behavior, and cognition in ADHD and chronic sleep-onset insomnia. Journal of the American Academy of Child & Adolescent Psychiatry. 2007;46(2):233–241.
- Gardiner C, Weakley J, Burke LM, et al. The effect of caffeine on subsequent sleep: a systematic review and meta-analysis. Sleep Medicine Reviews. 2023;69:101764. doi:10.1016/j.smrv.2023.101764.
- Gopukumar K, Thanawala S, Somepalli V, Rao TSS, Thamatam VB, Chauhan S. Efficacy and safety of Ashwagandha root extract on cognitive functions in healthy, stressed adults: a randomized, double-blind, placebo-controlled study. Evidence-Based Complementary and Alternative Medicine. 2021;2021:8254344. Importantly, this was not an ADHD trial, which is why I would use it only to contextualise claims made about ashwagandha and cognition.
- Weber W, Vander Stoep A, McCarty RL, Weiss NS, Biederman J, McClellan J. Hypericum perforatum (St John’s wort) for attention-deficit/hyperactivity disorder in children and adolescents: a randomized controlled trial. JAMA. 2008;299(22):2633–2641. doi:10.1001/jama.299.22.2633. The trial did not demonstrate a significant benefit for ADHD symptoms.
- National Center for Complementary and Integrative Health (NCCIH). ADHD and Complementary Health Approaches. NCCIH summarises the evidence for omega-3, melatonin, herbal preparations and other complementary interventions and emphasises that findings remain mixed.