Maritime Pine Bark: From a Frozen Ship to Prime
In the winter of 1535, the French explorer Jacques Cartier and his crew were trapped. Their ships were frozen into the St. Lawrence River in Canada, and scurvy was spreading through the men. Twenty-five of them had already died, and many of the others were too weak to bury them.
Local people showed the survivors how to make a tea from the bark of a tree. The sick men drank it, and most of them recovered.
Cartier wrote the story down, and it stayed in his journals for four hundred years. Then a French researcher named Jacques Masquelier read it and asked a simple question: what was in that bark?
What he found in the bark
Masquelier found that the bark was rich in a group of plant compounds called procyanidins. He then found the same compounds in a tree much closer to home: the maritime pine (Pinus pinaster), which grows along the Atlantic coast of southwest France. He developed a way to extract them from its bark.
Procyanidins are also found in grape seeds, cocoa and apples, but maritime pine bark is one of the richest sources. Its extract has since become one of the most studied plant extracts in the world. Most of that research uses Pycnogenol®, a standardised maritime pine bark extract, so that every study tests the same thing.
Procyanidins belong to a larger family of plant compounds called polyphenols, which are known as antioxidants. So the first thing researchers wanted to know was simple: does the extract actually raise antioxidant levels in the human body?
What it does in the blood
In a 2002 study, 25 healthy volunteers took 150 mg of pine bark extract every day for six weeks. Researchers measured the antioxidant capacity of their blood before, during and after.
During the six weeks, the antioxidant capacity of their blood rose by about 40%. Four weeks after they stopped taking the extract, it had almost returned to where it started. The participants' LDL cholesterol also went down, and their HDL cholesterol went up.
That last result pointed researchers towards the blood vessels themselves. If the extract changed what was in the blood, did it also change how the vessels carrying that blood worked?
What it does to blood vessels
The inner wall of your blood vessels produces a gas called nitric oxide. Nitric oxide relaxes the muscle in the vessel walls, the vessels widen, and more blood flows through.
In a 2007 double-blind, placebo-controlled study, healthy young men took pine bark extract for two weeks. Researchers then measured how much the blood vessels in their forearms could widen. Blood flow rose from 13.1 to 18.5 mL per minute per 100 mL of tissue. When the researchers blocked the body's production of nitric oxide, the effect disappeared. This showed that the pine bark worked by increasing nitric oxide.
Why that matters for men
An erection depends on blood flow, and nitric oxide is the signal that starts it. When a man is aroused, his body releases nitric oxide, the blood vessels in the erectile tissue widen, and blood flows in. When the body produces too little nitric oxide, the vessels don't widen as much, and the erection becomes weaker.
So researchers asked the obvious next question: if pine bark increases nitric oxide in blood vessels, could it help men with erectile problems?
The first study
In 2003, researchers in Bulgaria tested this on forty men aged 25 to 45 with erectile problems. They didn't start with pine bark. They started with L-arginine, an amino acid the body uses to make nitric oxide.
After one month on L-arginine alone, only 2 of the 40 men (5%) reported normal erections. In the second month, pine bark extract was added, and the number rose to 80%. In the third month, the pine bark dose was increased to 120 mg a day, and 37 of the 40 men (92.5%) reported normal erectile function.
The results were striking, but the study had no placebo group. Without one, nobody could be sure how much of the improvement came from the supplement and how much from the men simply expecting to get better.
The placebo-controlled trial
So in 2008, the same team ran a stricter trial. Fifty men with mild to moderate erectile dysfunction took either a placebo or pine bark extract with L-arginine aspartate for one month, then switched. Neither the men nor the researchers knew who was taking what. During the month on the combination:
- 70% of the men improved their erectile function score
- intercourse frequency doubled
- testosterone levels in the blood increased significantly
- cholesterol and blood pressure went down
A single research team can repeat its own result. The real test is whether a different team, in a different country, finds the same thing.
The study in Japan
In 2012, researchers in Japan ran their own placebo-controlled trial with men with mild to moderate erectile dysfunction. For eight weeks, the men took either a placebo or a daily supplement of 60 mg of pine bark extract with L-arginine and aspartic acid.
The men taking the supplement improved their erectile function scores, with the biggest changes in hardness of erection and satisfaction with intercourse. Their blood pressure went down, and their salivary testosterone rose slightly. No side effects were reported during the study.
A different team, a different country and a lower dose of pine bark, and the direction of the results was the same. Two of these trials also measured something researchers hadn't set out to study at first: testosterone.
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What happened to testosterone
None of these studies was designed as a testosterone study. They were looking at blood flow and erectile function. But testosterone was measured along the way, and it moved in the same direction each time:
- 2008 trial, 50 men: testosterone in the blood increased significantly during the month on pine bark and arginine.
- 2012 trial in Japan: salivary testosterone rose slightly over eight weeks.
- 2018 trial, 50 men with fertility problems: in a placebo-controlled crossover study of pine bark with amino acids and an oak wood extract, testosterone levels increased significantly, and the men's slightly raised blood pressure returned to normal.
These are small studies, and pine bark is not a testosterone treatment. But the same result appearing in three separate trials is why researchers keep looking at it.
What the research shows together
By 2023, enough controlled trials existed to combine them. A review in Frontiers in Endocrinology pooled three of them, with 184 men in total. Compared with the control groups, men taking pine bark with L-arginine had significantly better scores for erectile function, orgasm, sexual desire and overall satisfaction.
Every one of these studies has something in common: pine bark was never tested alone. It was always paired with L-arginine.
Why pine bark and arginine work together
The first study already showed the reason. L-arginine is the raw material your body uses to make nitric oxide, but on its own it did very little. Pine bark supports the enzyme that turns arginine into nitric oxide. One provides the material, and the other helps the body use it. Together, they produced the results neither showed alone.
Of course, an ingredient you take every day also has to be safe to take every day.
Is it safe for daily use?
Pine bark extract has one of the largest safety records of any plant extract. A 2024 review looked at 39 randomized, double-blind, placebo-controlled trials with 2,009 participants, who took it for between two weeks and six months. No serious side effects were found in any of the trials, or in its commercial use.
Proven effects when combined with arginine, a long safety record, and a dose that matches the research. That combination is the reason pine bark is in Prime.
Why it's in Prime
When we redesigned Prime, the research on pine bark gave us one clear rule: pine bark on its own is not enough. Every result in this article came from pine bark and arginine taken together.
So we built that pairing into the formula:
- 200 mg of maritime pine bark extract in every daily serving. That's more than the 120 mg taken in the final month of the 2003 study, and more than three times the 60 mg used in Japan.
- L-arginine, the raw material your body uses to make nitric oxide, and the ingredient every study paired with pine bark.
- L-citrulline, which your body converts into arginine, so pine bark always has material to work with.
This means you don't need to buy two separate supplements and work out the doses yourself. Both halves of the combination are in one daily serving of Prime.
The studies tested pine bark and arginine, not the full Prime formula, and their results describe what happened to the men who took part. But they are the reason pine bark is in Prime, and the reason it's paired the way it is.
It's a long way from a frozen ship in 1535 to a jar on your kitchen counter. But the question Masquelier asked about that bark led straight to the research behind one of Prime's key ingredients.
References
- Stanislavov R, Nikolova V. Treatment of erectile dysfunction with Pycnogenol and L-arginine. Journal of Sex & Marital Therapy, 2003. Link
- Stanislavov R, Nikolova V, Rohdewald P. Improvement of erectile function with Prelox: a randomized, double-blind, placebo-controlled, crossover trial. International Journal of Impotence Research, 2008. Link
- Aoki H, et al. Clinical assessment of a supplement of Pycnogenol® and L-arginine in Japanese patients with mild to moderate erectile dysfunction. Phytotherapy Research, 2012. Link
- Rohdewald P, Stanislavov R. Favourable effects of Prelox® on testosterone levels. Medical Research Archives, 2018. Link
- Nishioka K, et al. Pycnogenol, French maritime pine bark extract, augments endothelium-dependent vasodilation in humans. Hypertension Research, 2007. Link
- Devaraj S, et al. Supplementation with a pine bark extract rich in polyphenols increases plasma antioxidant capacity and alters the plasma lipoprotein profile. Lipids, 2002. Link
- Tian Y, et al. Efficacy of L-arginine and Pycnogenol® in the treatment of male erectile dysfunction: a systematic review and meta-analysis. Frontiers in Endocrinology, 2023. Link
- Pycnogenol® French maritime pine bark extract in randomized, double-blind, placebo-controlled human clinical studies. Frontiers in Nutrition, 2024. Link
- Cartier's "tree of life" and scurvy. Link