Trastornos Inflamatorios del Intestino

5-HTP is the direct precursor to serotonin; early clinical studies (1970s–1980s) tested it in children with ADHD, and it has been proposed as a complementary approach to address serotonergic deficits associated with the disorder. Evidence is preliminary and not from modern RCTs, but it has been reviewed in the ADHD supplement literature.

Acetyl-L-Carnitine (ALC) has been studied in multiple RCTs for ADHD in children; a multi-site 16-week placebo-controlled pilot (n=112) found no overall benefit, but a possible effect in the inattentive subtype. A second 6-week adjunctive RCT (n=40) found no significant additive benefit over methylphenidate. It is included in a 2023 network meta-analysis of 48 antioxidant studies across 12 agents for ADHD.

ADHD involves dopaminergic and noradrenergic dysfunction in prefrontal circuits, and tyrosine as their precursor has attracted investigational interest. However, medical authorities and clinical reviews conclude there is no high-quality evidence that L-tyrosine or NALT effectively treats ADHD. Tyrosine may modestly support catecholamine-dependent attention under depletion conditions but is not an established ADHD treatment.

Children with ADHD have lower blood levels of long-chain PUFAs including DHA compared to children without ADHD, and PUFA supplementation has shown improvements in ADHD-related symptoms. Two meta-analyses found positive but small effect sizes for LC PUFAs including DHA on behavioral symptoms in children and adolescents with ADHD. The DOLAB trial used algal oil DHA (600 mg/day) directly in underperforming school children.

Bacopa monnieri (brahmi) has consistently improved inattention, hyperactivity, and memory in children with ADHD across multiple RCTs and open-label studies, as confirmed by a 2025 systematic review. It is also highlighted in traditional Ayurvedic medicine for cognitive enhancement (medhya rasayana).

Caffeine enhances selective attention and reduces reaction time errors in healthy adults, and animal model systematic reviews show improved ADHD-like symptoms of inattention. Human clinical evidence in diagnosed ADHD populations remains limited, with most support coming from preclinical models and observational data. Caffeine is sometimes used informally by individuals with ADHD but is not a licensed treatment.

A meta-analysis of 7 RCTs (n=534 youth with ADHD) found omega-3 PUFA supplementation significantly improved ADHD clinical symptom scores (g=0.38), and a separate meta-analysis of 3 RCTs improved cognitive attention measures (g=1.09). Children with ADHD also show consistently lower DHA and EPA levels. Evidence supports omega-3s as a valuable adjunctive treatment for ADHD.

Cholinergic signaling underpins attentional circuits, and genetic evidence links choline transporter variants to ADHD risk. The choline form citicoline has shown improvements in attention and impulsivity in small RCTs in adolescents. Evidence for choline itself in diagnosed ADHD is preliminary but mechanistically grounded.

Multiple randomized, double-blind, placebo-controlled trials in healthy adults have found citicoline supplementation improves attentional performance, cognitive inhibition, and psychomotor speed. A pediatric ADHD pilot study found it well tolerated but without statistically significant symptom improvement. Evidence is most robust for attentional benefits in healthy populations; ADHD-specific evidence remains limited.

DHA and EPA from cod liver oil have been studied in ADHD, with some trials showing modest symptom improvements. Low omega-3 status is consistently observed in children with ADHD. A noted review of cod liver oil in children's health reported CLO reduces risk of ADHD in children.

DHA is a structural omega-3 fatty acid critical to brain cell membrane composition, and children with ADHD consistently show lower DHA levels than controls. Multiple meta-analyses of RCTs indicate modest but significant improvement in ADHD symptoms—particularly inattention—with omega-3 supplementation containing DHA and EPA; higher EPA content appears to drive most benefit.

DMAE (sold as Deaner/Deanol) was a prescription drug used for childhood behavioral and attentional problems from the 1960s through 1983. Multiple clinical studies, including at least one double-blind RCT comparing DMAE to methylphenidate (Ritalin) and placebo in 74 children, demonstrated significant improvement in attention and behavior with DMAE, though effect sizes were smaller than methylphenidate. The FDA classified DMAE as 'possibly effective' for ADHD before the drug was withdrawn. More recent evidence is sparse.

DHA is depleted in children with ADHD relative to typically developing peers. RCT evidence for DHA alone in ADHD is mixed—one double-blind RCT found no significant benefit at 345 mg/day—but combined EPA+DHA supplementation shows more promise for improving attention and behavior. DHA's structural role in brain development and neurotransmission underpins its mechanistic relevance.

EPA specifically improves focused attention and vigilance in children and adolescents with ADHD, particularly in those with low baseline EPA levels. A 12-week double-blind RCT (n=92) found EPA (1.2 g/day) improved focused attention (effect size 0.38, p=0.041) versus placebo. Meta-analyses confirm omega-3 PUFA supplementation improves ADHD symptom scores.

EPA is an omega-3 fatty acid with anti-inflammatory properties; meta-analyses of RCTs indicate that higher EPA content in omega-3 formulations is specifically associated with greater ADHD symptom improvement. Several large reviews and a 2023 Cochrane update evaluated EPA-containing formulations in ADHD children.

Children and adults with ADHD consistently show lower blood EPA and DHA levels than neurotypical controls. Multiple RCTs and meta-analyses have examined omega-3 supplementation for ADHD symptoms, with EPA showing the most consistent, modest positive effects on hyperactivity, inattention, and impulsivity. Fish oil omega-3s are considered a safe adjunct, not a replacement for first-line ADHD treatments.

Ginkgo biloba has been evaluated in multiple RCTs for ADHD in children, with results showing significant reductions in inattention and ADHD rating scale scores compared to placebo, though it is less effective than methylphenidate. A 2025 systematic review identified three qualifying RCTs, one of which (Shakibaei et al.) found 93.5% vs 58.6% response rates in treated vs placebo groups.

A 2024 systematic review (PubMed, Embase, Cochrane, Web of Science up to June 2023; 6 human studies) found that ginseng and ginsenosides may have beneficial effects on ADHD symptoms—particularly inattention—through dopaminergic and norepinephrinergic mechanisms. An observational clinical study in 18 children with ADHD (KRG 1,000 mg twice daily for 8 weeks) found significant improvements in omission errors and the Conners ADHD Rating Scale. Evidence quality remains limited by small samples and risk of bias.

GLA has been investigated in clinical trials for ADHD, with the 1989 Arnold et al. placebo-controlled comparison to D-amphetamine being the earliest RCT. More recent omega-3/GLA combination trials show weak to modest evidence of benefit. GLA alone has generally not demonstrated robust efficacy in ADHD, but its role as an adjuvant anti-inflammatory agent in combination with omega-3s continues to be investigated.

GPC supports attention via two complementary mechanisms: ACh augmentation in cortical attention networks, and enhancement of frontal dopamine tone. Human evidence shows GPC improved attention in cognitive impairment studies and acutely improved performance on attention-sensitive tests (Stroop, psychomotor vigilance) in healthy adults. No dedicated ADHD RCT exists yet.

A published randomized, double-blind, placebo-controlled trial administered PCSO-524 (GLM lipid extract) to 144 children and adolescents (aged 6–14) with clinical and subclinical ADHD symptoms for 14 weeks, reporting reduced inattention and hyperactivity and improved cognition versus placebo. Children with ADHD have lower blood levels of LC-PUFAs, and GLM's unique LC-PUFA combination is hypothesized to address this deficit. Evidence is limited to a small number of trials and findings require independent replication.

Iron is a cofactor for tyrosine hydroxylase, the rate-limiting enzyme in dopamine and norepinephrine synthesis, both central to ADHD pathophysiology. Children with ADHD consistently show lower serum ferritin levels than controls in meta-analyses, and a pilot RCT in iron-deficient children with ADHD found significant symptom improvement with ferrous sulfate supplementation.

An open-label pilot trial by Aker BioMarine in 18 boys (ages 7–11) with ADHD found improvements in EEG scores after 13 weeks of krill oil supplementation. Broader omega-3 PUFA RCTs show modest improvements in ADHD symptoms in children; krill-specific RCT evidence is limited but supported by DHA's documented role in prefrontal cortex function.

One RCT examined 800 mg/day L-carnosine as adjunctive therapy in drug-naïve children with ADHD, showing improved behavioral outcomes. A clinical review identified L-carnosine as showing therapeutic potential in neurodevelopmental disorders. Evidence is preliminary and based on a single small RCT.

L-theanine, an amino acid found in green tea, has been evaluated in ADHD for its effects on sleep and attention. A 2025 systematic review found L-theanine improved sleep efficiency in ADHD children, and its combination with caffeine may enhance attention. RCTs in boys with ADHD showed improved sleep quality with 400 mg/day.

The serotonergic system is implicated in ADHD, and tryptophan—as serotonin's precursor—has been investigated in multiple RCTs. A 2022 systematic review of 14 RCTs found mixed evidence for tryptophan's effects on attention and impulsivity in ADHD populations, with most studies using depletion rather than supplementation paradigms.

Clinical use of lemon balm for restlessness and attentional difficulties in children has been studied. A 2006 open multicenter trial in 918 children under 12 with restlessness and dyssomnias found that a valerian/lemon balm combination produced 70.4% improvement in restlessness. Kennedy et al. RCTs in adults also demonstrate improved attention task accuracy at 600 mg. Evidence in formally diagnosed ADHD populations is limited.

Lobeline underwent a proof-of-concept human study for ADHD (Martin et al., J Atten Disord 2013/2018; n=9 adults), finding modest improvements in working memory but no significant improvement in attention. A follow-on Phase 2 trial was registered but results were not published. Preclinical studies support a plausible mechanism via dopaminergic modulation.

Magnesium levels correlate inversely with ADHD symptom severity, and supplementation—often combined with vitamin B6—has shown reductions in hyperactivity and behavioral problems in children with ADHD in multiple RCTs. A 2019 meta-analysis confirmed significantly lower magnesium levels in ADHD versus controls. Typical studied doses are 6 mg/kg/day in children.

Melatonin is well-documented for treating sleep-onset insomnia in children with ADHD on stimulant medications, with multiple RCTs and reviews supporting its efficacy for sleep, though evidence for direct reduction of core ADHD symptoms (inattention/hyperactivity) is minimal. The PMC4170184 review (NIH) and NCCIH both recognize melatonin's role in ADHD-related sleep management.

Omega-3 fatty acids (EPA and DHA) are among the most studied nutritional supplements for ADHD; multiple meta-analyses and systematic reviews document modest but significant improvements in ADHD symptoms, particularly inattention, in children. The NCCIH and multiple PMC reviews list them as among the best-supported complementary approaches for ADHD.

Arachidonic acid (AA), a long-chain omega-6 PUFA, is formed from GLA and is a major brain phospholipid involved in neurotransmitter signaling relevant to ADHD. Children with ADHD have been reported to have lower blood AA levels. A higher prenatal omega-6:omega-3 ratio in cord blood was associated with more ADHD symptoms at ages 4 and 7. However, a 2023 Mendelian randomization study found no direct causal relationship between omega-6 fatty acids and ADHD.

A single small RCT (Akhondzadeh et al., 2005) compared passionflower tablets to methylphenidate in 34 children (ages 6–13) with DSM-IV ADHD over 8 weeks. No significant difference was found between groups on Parent and Teacher ADHD Rating Scales, and passionflower produced fewer side effects including less anxiety and appetite suppression. While promising, the study is preliminary and NCCIH states evidence remains insufficient to confirm efficacy.

Phosphatidylserine (PS) is a phospholipid component of neuronal cell membranes. A 2021 systematic review and meta-analysis of three RCTs (n=216 children) found a statistically significant effect of 200–300 mg/day PS on inattention symptoms in pediatric ADHD (ES=0.36, p=0.01). It is one of the few supplements with meta-analytic support specifically for pediatric ADHD inattention.

A randomized controlled trial in children with ADHD showed Pycnogenol (1 mg/kg/day for 4 weeks) significantly reduced hyperactivity and improved attention, concentration, and motor coordination. However, results across studies are mixed, and larger confirmatory trials are needed. A recent RCT compared Pycnogenol to methylphenidate.

Pine Bark extract (Pycnogenol®, from Pinus pinaster) has been evaluated in RCTs for pediatric ADHD, with a 2006 double-blind RCT (n=61 children, 4 weeks, 1 mg/kg/day) showing significant reductions in hyperactivity and inattention versus placebo. A 2022 RCT confirmed significant ADHD-RS improvements over placebo at 10 weeks.

Multiple RCTs and a 2024 systematic review of four trials (n=118) found that saffron (Crocus sativus, 20–30 mg/day) produced ADHD symptom reductions comparable to methylphenidate in children and adolescents. Saffron showed particular strength for hyperactivity, while methylphenidate was more effective for inattention.

A 12-week open-label pilot trial of L-Threonic Acid Magnesium Salt (LTAMS) in 15 adults with moderate ADHD showed clinically meaningful attention improvements in ~47% of participants. Preclinical work supports neurobiological effects relevant to ADHD, including NMDA receptor modulation and synaptic density enhancement.

A 2022 systematic review in Frontiers in Pharmacology (7 RCTs in children and adolescents with ADHD) found 'fair indication of efficacy and safety' for Valeriana officinalis in treating ADHD symptoms. A notable open-label study by Gromball et al. (2014) in 169 primary-school children showed a combined valerian-lemon balm preparation (640 mg valerian + 320 mg lemon balm daily for 7 weeks) significantly reduced hyperactivity, inattention, impulsivity, and sleep problems. Evidence remains preliminary, limited by small samples and absence of large-scale placebo-controlled trials.

Vitamin B6 (pyridoxine) serves as a coenzyme in the synthesis of dopamine, serotonin, GABA, and norepinephrine—neurotransmitters critically dysregulated in ADHD. Clinical studies, particularly those combining vitamin B6 with magnesium (the Mg-B6 regimen), show reductions in hyperactivity, aggression, and attention difficulties in children with ADHD.

Multiple observational and interventional studies show that children with ADHD have lower vitamin D levels, and RCTs combining vitamin D with magnesium found significant improvements in ADHD behavior scores. A clinical study found that increases in serum 25(OH)D from supplementation correlated with improvement in ADHD inattention symptoms.

Bacopa monnieri has been tested in children with ADHD in clinical trials. An open-label trial in 31 children found attention-deficit symptoms reduced in 85% of participants. A pediatric systematic review found small-to-medium effect sizes for improvements in hyperactivity and attention.

Multiple RCTs and systematic reviews show that zinc deficiency is common in children with ADHD, and supplementation (typically 15–55 mg/day elemental zinc) can reduce hyperactivity and impulsivity scores. Effect sizes are small to moderate and are most pronounced in zinc-deficient populations. A 2021 systematic review of nine RCTs confirmed improvements in ADHD symptom severity with zinc supplementation compared to placebo.

Adams et al. (Chinese Medicine, 2012) reviewed mugwort species specifically for ADHD treatment, representing the primary source linking A. vulgaris to this indication. The MAO-inhibitory phenolics and CNS-active volatile constituents provide mechanistic plausibility. Evidence is entirely traditional and review-based, with no dedicated human trials.

Vacha is a classical Ayurvedic herb used specifically for children's attention, intellect, and speech development. It is included in Ayurvedic formulations being clinically trialled for ADHD, though evidence for Vacha alone in ADHD is based on traditional practice rather than standalone controlled trials.