Obtained from the bark of the French maritime pine tree, pine bark extracts contain procyanidins which have antioxidant properties. Various formulations using different species have been marketed, vary in amounts of procyanidins, and are often promoted for use in chronic conditions. Pine bark extract showed antioxidant, anti-inflammatory ⁽⁶⁾, immunostimulant ⁽¹⁾, cardioprotective ⁽²⁰⁾, and neuroprotective ⁽³¹⁾ effects in preclinical studies. It may also have antimicrobial activities ^{(15) (16) (17)}. 

Preliminary clinical data suggest it may reduce menopausal ⁽⁸⁾, dysmenorrheic ⁽²⁷⁾, and osteoarthritic ^(9) (10) symptoms. A pine bark extract formulation improved oxidative stress and bone turnover markers in postmenopausal osteopenic women ⁽³⁹⁾, and improved nutrition and clinical status in critically ill patients ⁽⁴⁰⁾. Other data suggest pine bark extract may improve hyperpigmentation ⁽¹¹⁾, erythema ⁽¹²⁾, and symptoms of endometriosis ⁽¹³⁾ and lupus ⁽¹⁴⁾. Improvements in endothelial dysfunction ^(2) (33) and chronic venous insufficiency ⁽⁵⁾ were also reported, but a meta-analyses found no benefit with pycnogenol on blood pressure ⁽³⁶⁾, and insignificant effects cardiometabolic health ⁽³⁷⁾. Another meta-analysis recommended against pycnogenol for musculoskeletal pain ⁽³⁸⁾.

Pycnogenol may enhance memory in elderly participants ⁽⁷⁾, but studies in adults and children with ADHD yielded mixed results ^{(3) (4) (42)}. When used in conjunction with L-arginine, pycnogenol improved erectile dysfunction symptoms ^(18) (29). Preliminary data suggest pycnogenol may reduce some adverse effects of radiotherapy and chemotherapy ⁽³⁰⁾, but further research is needed. Systematic reviews have concluded that evidence is insufficient and that large-scale studies are needed to establish the value of various pine bark extract supplements for chronic disorders ^(34) (41).