Selenium Supplementation for ADHD
Selenium supplementation is not recommended for treating ADHD, as there is no evidence supporting its efficacy for this condition, and supplementation should only be considered if a documented selenium deficiency is confirmed through laboratory testing. 1
Evidence Against Selenium for ADHD
The available evidence does not support selenium supplementation for cognitive or behavioral disorders:
- No clinical trials exist examining selenium supplementation specifically for ADHD treatment 2, 3, 4
- The ESPEN guidelines explicitly state there is insufficient evidence to recommend selenium supplements for prevention or correction of cognitive decline, with very low quality evidence 1
- Reviews of nutritional supplements for ADHD do not identify selenium as having any supporting evidence for symptom improvement 2, 3, 4
Concerning Association with High Selenium Levels
One observational study found an unexpected association that warrants caution:
- Children with selenium concentrations above the 90th percentile had 2.5 times higher odds of ADHD diagnosis compared to those with normal concentrations 5
- This finding suggests that high selenium exposure may potentially be harmful rather than beneficial for neurodevelopment 5
When Selenium Supplementation IS Appropriate
Selenium should only be supplemented when a documented deficiency exists:
- Measure plasma selenium levels before considering any supplementation 6, 7
- Always measure CRP simultaneously, as inflammation significantly reduces plasma selenium levels and can lead to misinterpretation 6, 7
- Supplementation is indicated when plasma selenium is <0.4 mmol/L (<32 mg/L) 7
Safe Dosing If Deficiency Confirmed
If laboratory testing confirms selenium deficiency:
- Start with 100 μg/day for mild deficiency 6, 7
- For severe deficiency (plasma selenium <0.4 μmol/L), consider up to 400 μg/day for 7-10 days only, then reduce to maintenance dosing 6, 7
- Never exceed 200 μg/day for long-term supplementation due to narrow margin between safe and toxic doses 1
Critical Safety Warnings
The risks of selenium supplementation must be carefully considered:
- Narrow therapeutic window: There is only a small margin between safe and toxic doses 1
- Toxicity threshold: Upper toxicity limits occur at plasma selenium levels of 6-12 μmol/L 6, 7
- Selenosis symptoms include headache, hair and nail loss, skin rash, and neurological symptoms 6
- Long-term risks: Chronic overexposure is associated with type 2 diabetes and high-grade prostate cancer 6, 7
Monitoring Requirements
If supplementation is initiated for confirmed deficiency:
- Recheck plasma selenium and CRP after 3-6 months of supplementation 6
- Monitor for signs of toxicity including hair loss, nail changes, and neurological symptoms 6
Alternative Evidence-Based Approaches for ADHD
Rather than selenium, consider nutritional interventions with actual supporting evidence:
- Zinc supplementation has two positive randomized controlled trials supporting its use in ADHD 2
- Essential fatty acids (EPA, DHA, and γ-linolenic acid mix) have mixed but some positive evidence 2, 3, 4
- Broad-spectrum micronutrient formulas (containing multiple vitamins and minerals) showed efficacy in one double-blind RCT in adults with ADHD 8
- RDA/RDI multivitamin/mineral supplements are reasonable as a general pediatric health intervention 4