Pine Bark

Maritime pine, also called cluster pine (pinheiro bravo in Portuguese, pino marítimo or pino resinero in Spanish), is an evergreen conifer that grows to about 40 m, according to the Gymnosperm Database. Male and female cones grow on the same tree. Its bark is unusually thick, deeply fissured into scaly plates patterned in red-brown, blackish, and buff, and that thick bark is the raw material for the extracts. The needles grow in pairs, occasionally threes, and are stout, about 2 mm thick and 12–25 cm long, staying on the tree for one and a half to three years. The cones are glossy chestnut brown, usually 9–18 cm long, ripen in the second year after pollination, and sometimes stay closed on the tree for years. The species name comes from the Italian pinastro.

Plants of the World Online (Kew) accepts Pinus pinaster Aiton, published in 1789, as native to the western and central Mediterranean: Portugal, Spain, France including Corsica, Italy including Sardinia and Sicily, the Balearic Islands, Morocco, Algeria, and Tunisia. It has been introduced to Britain, Ireland, Greece, Türkiye, the Canary Islands, Madeira, and several Australian states, among other places. POWO accepts three subspecies: subsp. pinaster, the Atlantic form of western France, Portugal, and Spain, which includes the Landes forest; subsp. escarena; and subsp. renoui. Supplement papers, including those by Horphag scientists, often call the source “subsp. atlantica,” but POWO lists that name as not validly published and treats it as a synonym. The older name Pinus maritima is ambiguous: Lamarck’s P. maritima is a synonym of subsp. pinaster, but P. maritima Mill. is a synonym of Aleppo pine, P. halepensis.

Rohdewald (International Journal of Clinical Pharmacology and Therapeutics 2002), a long-time Pycnogenol researcher, described the extract as procyanidins, ranging from single catechin units to chains of seven or more, together with taxifolin and phenolic acids. Bayer and Högger (Frontiers in Nutrition 2024) report that Pycnogenol meets the United States Pharmacopeia monograph for “Pine extract” and is standardized to 65–75% procyanidins. Grape seed extract also contains proanthocyanidins (NCCIH), and so do peanut skins, cranberries, and many barks. Because the common color tests for these compounds cannot tell one plant source from another, Gafner and colleagues (Journal of Natural Products 2023) note that pine bark is itself among the cheaper materials used to fortify or substitute cranberry and grape seed extracts. Telling sources apart takes fingerprinting methods such as HPLC or mass spectrometry.

Pine bark marketing often opens with the French explorer Jacques Cartier, whose ships were trapped in the ice near Stadacona, now Quebec City, in the winter of 1535–36. Houston (Canadian Bulletin of Medical History 1990) recounts that about 75 men died or were given up for dead from scurvy before Don Agaya, an Indigenous man who had recovered, showed the French how to boil the bark and leaves of a tree called anneda. Historians have proposed eleven different trees. Houston judged eastern white cedar (Thuja occidentalis) the best candidate, while others argued for eastern white pine. Whichever it was, it was a North American evergreen, not the maritime pine used for Pycnogenol.

The modern source is the Landes de Gascogne. According to Britannica, maritime pines were planted from 1801 to fix the shifting coastal dunes, and in the second half of the 19th century the marshy plain behind them was drained and planted for timber and turpentine. NutraIngredients reports that Napoleon III’s law of 1857 required landowners to drain and plant. The Gymnosperm Database calls the result the largest artificial forest in Europe, about 8,200 km². Fires in 1937 and 1950 destroyed much of it before replanting, and the bark used for Pycnogenol is left over from the region’s timber industry (NutraIngredients).

The chemistry began with the French researcher Jack Masquelier, who in 1947 isolated oligomeric proanthocyanidins from peanut skins (Weseler and Bast, Nutrition Journal 2017). The company that still sells products under his name says that when peanut supplies changed around 1950 he turned to Landes pine bark, was granted French patent 1,427,100 in 1965, and launched a pine bark product called Flavan in France in 1968; he later developed grape seed OPCs. His US patent 4,698,360, filed in 1985 by an Aquitaine research company and Horphag Overseas and granted in 1987, described proanthocyanidins as part of a chemical group it called “pycnogenols.” Horphag Research, founded in Berlin in 1925 by Charles Haimoff, launched Pycnogenol in Europe in 1987 and the US in 1991, and says it was first registered as an over-the-counter medicine in Switzerland in 1991 for venous insufficiency (NutraIngredients 2025). The two companies tell the origin story differently.

Only part of the extract reaches the blood intact. Grimm and colleagues (BMC Clinical Pharmacology 2006) gave 11 volunteers a single 300 mg dose of Pycnogenol and found catechin, caffeic acid, ferulic acid, taxifolin, and a metabolite called M1, a valerolactone, in their plasma, some of it still detectable 14 hours later. In a 2024 review, Bayer and Högger, who has received Horphag research grants, describe the small molecules as absorbed in the small intestine, while the larger procyanidin chains are broken down by gut bacteria into M1. These compounds have been found in blood cells, joint fluid, and saliva, and are cleared through the kidneys.

The main proposed mechanism is on blood vessels. In a Horphag-funded crossover trial, Enseleit and colleagues (European Heart Journal 2012) gave 23 people with coronary artery disease 200 mg a day for eight weeks. Flow-mediated dilation, a measure of how well arteries widen, rose from 5.3% to 7.0%, and an oxidative stress marker fell, but blood pressure, inflammation markers, and platelet adhesion did not change. Rohdewald’s 2002 review attributes a mild blood pressure effect to inhibition of the enzyme ACE. Pütter and colleagues (Thrombosis Research 1999), with Rohdewald as co-author, found that 100–125 mg prevented the rise in platelet clumping caused by smoking in smokers, an effect similar to 500 mg of aspirin, yet unlike aspirin it did not lengthen bleeding time.

The immune findings are laboratory and animal work. MSKCC cites a mouse study showing immune-stimulating effects, and Verlaet and colleagues (Nutrients 2019) found in cell experiments that Pycnogenol activated toll-like receptors, the immune sensors TLR1/2 and TLR2/6, while its gut-derived metabolites had anti-inflammatory effects. These results are the basis for caution in autoimmune disease, but no human study has shown harm; a small pilot in 11 people with lupus (Stefanescu and colleagues, Phytotherapy Research 2001) actually reported lower disease activity scores with the extract. Antioxidant claims rest mostly on test-tube chemistry and blood markers rather than clinical outcomes.

The Cochrane review by Robertson and colleagues (2020) is the best overall picture. Its 27 randomized trials lasted four weeks to six months, and only 4 were judged at low risk of bias; 22 were unclear. Every pooled result was rated low or very low certainty, and the authors could not draw definitive conclusions for any condition. They reported that the manufacturer funded 20 of the 27 trials, that manufacturers did not respond to requests for information, and that publication bias was possible. Many of the positive Pycnogenol trials outside Cochrane’s selection come from a single Italian group led by Gianni Belcaro, often published as registry or supplement studies. Funding, small size, and short duration should be kept in mind for every finding below.

Blood pressure and metabolic risk have the most data, and they conflict. Fogacci and colleagues (Angiology 2020) pooled 7 double-blind trials with 626 people and found no significant effect on systolic, diastolic, mean arterial, or pulse pressure. Mohammadi and colleagues (2025), whose authors declared no competing interests, pooled 27 trials with 1,685 people and found systolic pressure 2.26 mm Hg lower, diastolic 2.62 mm Hg lower, fasting glucose 6.25 mg/dL lower, HbA1c 0.32 percentage points lower, and LDL cholesterol 5.07 mg/dL lower, with no change in HDL, triglycerides, or insulin. The independent Stanford trial by Drieling and colleagues (2010) randomized 130 people at raised heart risk to 200 mg of a Japanese pine bark extract or placebo for 12 weeks and found no difference in blood pressure, cholesterol, glucose, or C-reactive protein. Liu and colleagues (Life Sciences 2004) found that 58 people with high blood pressure taking 100 mg of Pycnogenol could manage on a lower dose of nifedipine.

Leg veins and the eyes were the original vascular targets. Arcangeli (Fitoterapia 2000) randomized 40 people with chronic venous insufficiency to 100 mg three times daily or placebo for two months; swelling, heaviness, and pain fell with the extract, edema and pain disappeared in about 60%, and venous blood flow did not change. Koch (Phytotherapy Research 2002), in an open trial of 40 patients, found that 360 mg of Pycnogenol a day reduced leg circumference over four weeks while 600 mg of horse chestnut extract did not do so significantly. Cochrane rated the two venous trials it included, 60 people in total, very low certainty. In diabetic retinopathy, a Horphag-funded trial by Steigerwalt and colleagues (Journal of Ocular Pharmacology and Therapeutics 2009) in 46 people reported less retinal swelling, and 18 of 24 treated patients felt their vision improved.

Erectile dysfunction research almost always pairs the extract with L-arginine. Stanislavov and Nikolova (Journal of Sex and Marital Therapy 2003) gave 40 men L-arginine for three months, adding Pycnogenol in months two and three; normal erections rose from 5% after L-arginine alone to 80% and then 92.5%, but there was no placebo group. Ledda and colleagues (BJU International 2010) tested Prelox, a Horphag combination of pine bark extract and L-arginine aspartate, in 124 men aged 30–50; the erectile function score rose from 15.2 to 27.1 over six months versus 15.1 to 19.0 on placebo. A 2026 review for the French urology societies (Lebâcle and colleagues, French Journal of Urology) found only modest, low-certainty signals for Pycnogenol and concluded that the evidence does not support routinely recommending herbal treatments for ED. For ADHD, Trebatická and colleagues (European Child and Adolescent Psychiatry 2006), a trial Cochrane lists as Horphag-funded, gave 61 children 1 mg/kg a day for four weeks and reported less hyperactivity and better attention, with symptoms returning a month after stopping. In adults, Tenenbaum and colleagues (Journal of Attention Disorders 2002) found neither Pycnogenol nor methylphenidate better than placebo in 24 people. Weyns and colleagues (Journal of Functional Foods 2022), using product and blinding supplied by Horphag, randomized 88 children for ten weeks; teachers rated total and hyperactivity scores better with both pine bark extract and methylphenidate than placebo, but only methylphenidate improved inattention. In asthma, Lau and colleagues (Journal of Asthma 2004), another Horphag-funded trial, reported better lung function and less rescue inhaler use in 60 children aged 6–18.

Joints and skin round out the list. Cisár and colleagues (Phytotherapy Research 2008) gave 100 people with mild to moderate knee osteoarthritis 150 mg a day or placebo for three months; WOMAC scores and pain improved and painkiller use fell with the extract. Cochrane lists it as Horphag-funded, and Rohdewald was a co-author. MSKCC notes that a review of supplements for musculoskeletal pain recommended against pine bark, and the German Society for Rheumatology (Keyßer and colleagues, Zeitschrift für Rheumatologie 2026) does not recommend it for inflammatory joint disease, though it says rheumatologists need not discourage patients who choose it for osteoarthritis. For melasma, an uncontrolled study by Ni and colleagues (Phytotherapy Research 2002) treated 30 women, and a placebo-controlled Brazilian trial by Lima and colleagues (Journal of the European Academy of Dermatology and Venereology 2021) added 75 mg twice daily to a standard bleaching cream and sunscreen in 44 women for 60 days; melasma scores fell 49% with the extract versus 34% with placebo.

Pine bark extract is sold as capsules and tablets of standardized dry extract, alone or in combinations. Pycnogenol is the standard against which others are compared and is standardized to 65–75% procyanidins (Bayer and Högger). The Cochrane review lists several other branded extracts tested in trials, including Oligopin, Flavangenol, PineXol, and Enzogenol, along with the combination products Prelox and Lady Prelox, which add L-arginine. LiverTox notes that extracts are made from P. pinaster, radiata pine (P. radiata) from New Zealand, and Masson pine (P. massoniana) from China, and Cochrane includes trials of Korean red pine (P. densiflora). These are different extracts, so results from one cannot be assumed for another. A label percentage of “OPCs” or “proanthocyanidins” does not confirm the species, because the usual tests measure the compound class rather than its source (Gafner and colleagues).

Doses in trials ranged from 50 mg to 360 mg a day, most often 100–200 mg, which LiverTox gives as the typical Pycnogenol range. WebMD’s monograph cites 50 mg two or three times daily. Children’s trials used 1 mg per kg of body weight a day (Trebatická) or 20–40 mg a day by body weight (Weyns). Trials lasted four weeks to six months, and the osteoarthritis trial by Cisár gave the extract with meals. Combination ED products contain much larger amounts of L-arginine alongside the pine bark.

Regulation varies. In the United States, pine bark extract is sold as a dietary supplement, and Horphag says Pycnogenol is also registered as an over-the-counter medicine in Switzerland and several South American countries. We found no authorized EU health claim for pine bark extract on its own; Horphag’s chief executive told NutraIngredients in 2025 that no health claims had been approved in Europe or the US, while Korea’s food safety ministry had granted three. The one favorable EFSA opinion involving pine bark (EFSA Journal 2013) concerned Limicol, an eight-ingredient cholesterol supplement containing red yeast rice with monacolin K, which EFSA notes is also known as lovastatin; EFSA stressed that no evidence was provided for an LDL-lowering effect of any single ingredient.