Pine Bark Extract (Pycnogenol)

Several biological actions of Pycnogenol are proposed to explain why it might improve ADHD symptoms:

• Powerful antioxidant activity / lowers oxidative stress. ADHD has been linked in some studies to markers of oxidative damage; Pycnogenol is a polyphenol-rich extract that increases total antioxidant status and reduces markers of oxidative DNA damage in children with ADHD. This antioxidant effect may protect neurons and improve cognitive function. Jeffrey Dach MD
• Modulation of catecholamines / neurotransmitters. Some clinical studies measured changes in urinary catecholamine excretion after treatment and reported reductions; the hypothesis is Pycnogenol may help rebalance dopamine/norepinephrine signalling which are central to attention and hyperactivity. Academia
• Improved microcirculation / nitric oxide effects. Pycnogenol can enhance endothelial function and nitric-oxide–mediated blood flow; better cerebral microcirculation is one plausible route to improved attention and cognition. ScienceDirect
• Anti-inflammatory and immunomodulatory effects. Inflammation and immune differences have been proposed in ADHD; Pycnogenol has anti-inflammatory actions which could contribute to benefit. herbalgram.org

Clinical-trial dosing (what’s actually been tested):

• Pediatric trials (most frequently cited): 1 mg per kg body weight per day (given once daily) was used in the randomized trials of children with ADHD. Typical trial duration was 4 weeks in the early trials. For example, the Trebatická et al. randomized, double-blind trial used 1 mg/kg/day for 4 weeks and reported improvement vs placebo. SpringerLink
• Planned/longer trials: A later phase-III protocol (multicentre) planned a 10-week randomized comparison of Pycnogenol vs methylphenidate and placebo in paediatric patients (protocol available). That trial was designed with longer exposure (10 weeks) to better compare clinical effects. BioMed Central
• Adult dosing (general supplements, not ADHD-specific trials): common supplement formulations for adults (across indications) range 50–150 mg/day in divided or single doses; specific ADHD studies in adults are limited, so adult dosing for ADHD is not established by high-quality RCTs. Use trial dosing or product monograph as guide and consult a clinician. Pycnogenol

How it was given in the trials (form / timing):

• Oral Pycnogenol capsules/tablets (standardized extract). In the pediatric RCTs the daily dose was calculated from body weight (1 mg/kg) and given once daily. Refer to the trial papers for exact formulation/manufacturer details. SpringerLink

Practical, evidence-based summary you can follow (if considering it):

• Children: the evidence-based trial dose = 1 mg/kg/day, given orally, for at least 4 weeks (some protocols extend to 8–10 weeks for fuller assessment). If symptoms are assessed at 4 weeks with partial benefit, clinicians in protocols considered longer treatment windows (e.g., 8–10 weeks) to evaluate response. SpringerLink
• Adults: no well-established ADHD RCT dosing; commonly used oral dosing for other cognitive uses is 50–150 mg/day. If you’re an adult considering Pycnogenol for attention, discuss with your clinician. Pycnogenol

Key randomized clinical trials

1. Trebatická J. et al., 2006 — “Treatment of ADHD with French maritime pine bark extract, Pycnogenol®”
2. Double-blind, randomized, placebo-controlled study in children (n≈61): 1 mg/kg/day for 4 weeks; reported reduced hyperactivity and improved attention vs placebo. (European Child & Adolescent Psychiatry / related publications of that cohort). SpringerLink
3. Link: Springer article entry. SpringerLink
4. Chovanová Z. et al., 2006 — Free Radical Research (and related biochemical study)
5. Randomized, double-blind, placebo-controlled trial measuring antioxidant markers (glutathione, 8-oxo-guanine) in children with ADHD; Pycnogenol improved total antioxidant status and reduced markers of oxidative DNA damage. This provides a mechanistic/biomarker complement to clinical outcomes. Jeffrey Dach MD
6. Phase-III trial protocol / multicentre RCT (2017 protocol published)
7. A 10-week randomized, double-blind trial protocol comparing Pycnogenol®, methylphenidate (MPH) and placebo in 144 paediatric ADHD/ADD patients — the protocol is publicly available (Trials journal). (Note: a protocol describes planned study design; check for later full results from that trial.) BioMed Central

Reviews and analyses

• Reviews of mechanisms & clinical outcomes (recent reviews summarize the small RCTs and mechanistic data, concluding that some trials show benefit but evidence is limited and further large trials are needed). Examples: Gavin Publishers review (2024/2025), and other narrative reviews summarizing the 2006 trials and mechanistic studies. Gavin Publishers