Pycnogenol is a standardised extract from the bark of French maritime pine (Pinus pinaster). Like grape seed extract and cocoa polyphenols, it’s rich in proanthocyanidins—a class of polyphenolic compounds that act as antioxidants.

The name “Pycnogenol” comes from the Greek root “pycno” meaning dense or packed together, referring to the polymerised nature of its constituent flavonoids. The extract typically contains about 65-75% procyanidins (polymeric flavonoids including catechins and epicatechins), along with smaller amounts of phenolic acids like caffeic acid and ferulic acid 1.

Pine bark preparations have a surprisingly long history. Accounts suggest that indigenous peoples in North America used pine bark teas for various ailments, and the French explorer Jacques Cartier reportedly used such preparations during his 1535 expedition when his crew suffered from scurvy. While we now understand this was likely due to vitamin C content rather than procyanidins, it shows people have been experimenting with pine bark for centuries.

Today’s standardised Pycnogenol extract has been studied for applications ranging from urinary tract health to cardiovascular function. Here’s what the research actually tells us.

What are the benefits of Pycnogenol?

1. Pycnogenol may help with recurrent UTIs and interstitial cystitis

This is perhaps the most relevant finding for bladder health. Urinary tract infections affect roughly 150 million people worldwide each year, and about a quarter of women who develop bacterial cystitis will experience recurrent infections within six months 2.

Interstitial cystitis presents a different challenge altogether. It’s a chronic inflammatory bladder condition causing pelvic pain, urinary frequency, urgency, and nocturia, but without bacterial infection. Patients often develop sleep disturbances, anxiety, and depression as secondary issues.

A controlled study of 64 patients with either recurrent UTIs or interstitial cystitis found that Pycnogenol supplementation (150 mg daily for two months) reduced symptoms and signs more effectively than cranberry 3.

My take: This is actually promising for a supplement study. The mechanism appears related to anti-inflammatory and antioxidant effects, plus reduced bacterial adhesion to bladder cells. However, with only 64 participants, I wouldn’t abandon conventional treatments based on this alone. It might be worth discussing with your urologist as an adjunct approach.

2. Pycnogenol may reduce cold symptoms

A controlled study of 146 participants with common colds found that Pycnogenol helped reduce cold symptoms, shortened illness duration, and prevented some complications like bronchitis 4.

The common cold, while usually mild, can persist with coughing for up to three weeks after the initial infection clears. Symptoms typically peak around day three after onset.

Worth noting: Taking Pycnogenol at the onset of a cold might provide some benefit, but this is a single study with a relatively small sample. I wouldn’t stock up on it as your primary cold remedy just yet.

3. Pycnogenol shows promise for cardiometabolic health

Cardiometabolic disease describes a spectrum that begins with insulin resistance and can progress through metabolic syndrome and prediabetes to type 2 diabetes and cardiovascular disease. These conditions share overlapping risk factors: overweight, poor lipid profiles, and elevated blood pressure.

A meta-analysis of 24 randomised controlled trials involving 1,594 participants found that oral Pycnogenol significantly reduced:

Fasting blood glucose (-5.86 mg/dL)
Glycated haemoglobin (-0.29%)
Systolic blood pressure (-2.54 mmHg)
Diastolic blood pressure (-1.76 mmHg)
Body mass index (-0.47 kg/m²)
LDL cholesterol (-7.12 mg/dL)

It also increased HDL cholesterol (+3.27 mg/dL) 5.

The honest truth: These numbers look impressive in aggregate, but the effect sizes are quite modest. A 5.86 mg/dL drop in fasting glucose, for instance, is unlikely to move someone from diabetic to non-diabetic status. Think of Pycnogenol as potentially helpful alongside lifestyle changes, not as a replacement for them.

4. Pycnogenol may support blood pressure regulation

High blood pressure (systolic ≥140 mmHg or diastolic ≥90 mmHg) contributes to an estimated 54% of strokes and 47% of ischaemic heart disease cases worldwide. The WHO estimates about 7.5 million annual deaths are directly related to hypertension.

A meta-analysis of 12 randomised controlled trials with 922 participants found that Pycnogenol (doses between 60-200 mg daily) reduced systolic blood pressure by 3.22 mmHg and diastolic by 1.91 mmHg 6.

Subgroup analysis revealed that systolic effects were more pronounced when Pycnogenol was combined with other herbs, while diastolic effects were stronger in studies lasting more than 12 weeks.

Reality check: A 3 mmHg reduction in systolic pressure isn’t nothing, but it’s also not replacing your blood pressure medication. The NHS recommends lifestyle modifications as first-line treatment for mild hypertension 7, and Pycnogenol could potentially complement that approach.

5. Pycnogenol may reduce C-reactive protein (CRP)

CRP is an inflammatory marker produced by the liver during infection and tissue damage. While traditionally associated with acute inflammation, elevated CRP also indicates chronic inflammatory processes linked to cardiovascular disease, certain cancers, and autoimmune conditions.

A meta-analysis of 5 randomised controlled trials with 324 participants suggested Pycnogenol supplementation reduced CRP levels 8. However, results showed high heterogeneity. Subgroup analysis found the effect was more consistent with doses exceeding 150 mg daily and in participants over 55 years old.

The catch: High heterogeneity in meta-analyses makes me cautious. It suggests the studies varied considerably in their methods or populations, making it harder to draw firm conclusions.

6. Pycnogenol has limited effects on lipid profiles

A systematic review of 14 randomised controlled trials (1,065 participants) found that Pycnogenol increased HDL cholesterol concentrations, but showed no significant changes in total cholesterol, triglycerides, or LDL cholesterol 9.

My honest assessment: If you’re looking for a supplement to improve your cholesterol panel, Pycnogenol probably isn’t your best option. The HDL increase is nice, but the lack of LDL reduction limits its usefulness. Fish oil has more robust evidence for cardiovascular lipid effects.

7. Pycnogenol may benefit chronic venous insufficiency

Chronic venous insufficiency occurs when leg vein valves function poorly, leading to reduced venous return, blood pooling, and inflammation. Symptoms include leg pain, swelling, heaviness, cramping, and burning. In severe cases, skin changes, eczema, and venous ulcers can develop.

An 8-week comparative study of 142 patients with chronic venous insufficiency divided participants into three groups: Pycnogenol alone (150 mg daily), compression stockings alone, or both combined 10.

Results showed that compared to compression stockings alone, the Pycnogenol group demonstrated significant improvements in skin blood flow, ankle swelling, and symptom scores.

In practice: Compression therapy remains the gold standard for chronic venous insufficiency. But if you’re already using compression stockings and still symptomatic, Pycnogenol might offer additional benefit. Discuss with your vascular specialist.

8. Pycnogenol may support cognitive function

Mild cognitive impairment affects an estimated 10-20% of adults over 65. In some cases, it progresses to dementia, with about 10-15% of people with mild cognitive impairment developing dementia annually.

A 12-week study of 150 healthy adults aged 55-70 found that Pycnogenol improved cognitive function and reduced markers of oxidative stress compared to those not taking it 11.

A separate 8-week study of 33 university students (aged 18-27) showed improvements in concentration, memory, executive function, and mood scores 12.

Worth considering: These are interesting findings, but both studies are small. If you’re looking for cognitive support supplements with stronger evidence, fish oil (for omega-3s) and possibly ginkgo biloba have larger research bases, though results remain mixed across the board.

9. Pycnogenol may slow skin ageing

Photoageing from ultraviolet light exposure is the largest external contributor to skin ageing. UV radiation damages DNA and activates pathways that break down collagen while inhibiting new collagen production.

A small study found that Pycnogenol (75 mg daily for 12 weeks) increased skin moisture and elasticity, with more pronounced effects in those with dry skin. Researchers attributed this to increased production of hyaluronic acid and type I collagen 13.

Another study in 112 women under 60 found that a related pine bark extract (Flavangenol, a Japanese formulation) improved several photoageing markers including sunburn sensitivity, pigmentation, and skin roughness 14.

My take: Skin health claims are notoriously difficult to verify objectively. The mechanisms are plausible, but I’d prioritise sunscreen and vitamin A derivatives (retinoids) over Pycnogenol for anti-ageing purposes.

10. Pycnogenol may help manage diabetes and its complications

Diabetes is fundamentally a progressive vascular disease affecting muscles, skin, heart, kidneys, and brain. Long-term complications include retinopathy, nephropathy, neuropathy, hearing impairment, and cardiovascular disease.

A small double-blind controlled study found that Pycnogenol (125 mg daily for 12 weeks) reduced fasting plasma glucose by 23.7 mg/dL in diabetic patients, compared to only 5.7 mg/dL in controls. Glycated haemoglobin decreased by 0.8% versus 0.1% in controls 15.

Another double-blind study found Pycnogenol improved retinal vascularisation and reduced endothelial cell permeability, potentially slowing diabetic retinopathy progression 16.

A word of caution: If you have diabetes, don’t adjust your medications based on these findings. The blood glucose reductions are meaningful but not sufficient to replace proper diabetes management. See the contraindications section below regarding hypoglycaemic drug interactions.

11. Pycnogenol may reduce osteoarthritis symptoms

Osteoarthritis is the most common joint disease, particularly affecting middle-aged and older adults. Risk factors include age, female sex, excess weight, joint overuse, low bone density, and previous knee injuries (which increase risk nearly fourfold).

A 3-month double-blind controlled study of 37 patients with knee osteoarthritis found that Pycnogenol (50 mg three times daily) improved:

Pain (43% reduction)
Stiffness (35% reduction)
Physical function (52% improvement)
Overall WOMAC index (49% improvement) 17

My assessment: These percentage improvements are actually fairly impressive for a supplement study. However, 37 patients is a small sample. Glucosamine has a much larger research base for osteoarthritis, though Pycnogenol might be worth trying if glucosamine hasn’t worked for you.

What are the side effects of Pycnogenol?

Most studies conclude that Pycnogenol is relatively safe at doses ranging from 50-450 mg daily for up to one year. Side effects are typically mild and uncommon.

Reported adverse effects include:

Gastrointestinal discomfort (mostly preventable by taking with food)
Dizziness
Headache
Nausea
Fatigue
Drowsiness
Mouth ulcers
Bad breath
Skin inflammation
Irritability
Hypoglycaemia (in susceptible individuals)
Urinary problems

Safety precautions (7 contraindications)

1. Pregnancy and breastfeeding: Do not use if pregnant, breastfeeding, or planning to become pregnant. Safety data in these populations is insufficient.

2. Children under 6: Not recommended due to lack of safety data.

3. Liver or kidney impairment: Avoid use if you have compromised liver or kidney function, as safety hasn’t been established in these populations.

4. Autoimmune conditions: Do not use if you have conditions such as multiple sclerosis, systemic lupus erythematosus, or rheumatoid arthritis. Pycnogenol may stimulate the immune system and potentially worsen autoimmune activity.

5. Bleeding disorders or anticoagulant use: Pycnogenol may affect blood clotting. Avoid if you have a bleeding disorder, take anticoagulant medications, or are scheduled for surgery within two weeks.

6. Diabetes medications: Use caution if taking hypoglycaemic drugs, as Pycnogenol may lower blood sugar and increase the risk of hypoglycaemia. Monitor blood glucose closely and consult your doctor.

7. Immunosuppressant medications: Do not combine with immunosuppressants, as Pycnogenol may reduce their effectiveness. Relevant medications include:

Azathioprine
Basiliximab
Ciclosporin (cyclosporine)
Daclizumab
Muromonab-CD3
Mycophenolate
Tacrolimus
Sirolimus
Prednisone and other corticosteroids

How much Pycnogenol should you take?

There’s currently insufficient evidence to establish a definitively safe and effective dose for specific conditions. Clinical studies have used daily doses ranging from 50-360 mg.

General guidance:

Start with a lower dose (50-100 mg daily)
Take with or after meals to minimise gastrointestinal side effects
Common study doses for cardiovascular benefits: 100-200 mg daily
Common doses for osteoarthritis: 100-150 mg daily (often divided into 2-3 doses)

If you’re taking any of the medications listed in the contraindications section, or have diabetes or an autoimmune condition, check with your doctor before trying Pycnogenol.

References

Rohdewald P. A review of the French maritime pine bark extract (Pycnogenol), a herbal medication with a diverse clinical pharmacology. Int J Clin Pharmacol Ther. 2002;40(4):158-68. PubMed
Flores-Mireles AL, et al. Urinary tract infections: epidemiology, mechanisms of infection and treatment options. Nat Rev Microbiol. 2015;13(5):269-84. PubMed
Ledda A, et al. Pycnogenol supplementation in recurrent urinary tract infection and interstitial cystitis. Minerva Urol Nefrol. 2022;74(3):339-345. PubMed
Belcaro G, et al. Pycnogenol supplementation reduces pain and stiffness following treatment of symptomatic osteoarthritis. Phytother Res. 2008;22(4):518-23. PubMed
Pourmasoumi M, et al. The effect of Pycnogenol on cardiometabolic risk factors: a systematic review and meta-analysis. Br J Nutr. 2019;122(8):841-851. PubMed
Zhu Y, et al. The effect of Pycnogenol on blood pressure: a meta-analysis of randomized controlled trials. Phytomedicine. 2020;66:153135. PubMed
NHS. High blood pressure (hypertension) - Treatment. NHS
Malekahmadi M, et al. Effects of Pycnogenol on cardiometabolic health: a systematic review. Br J Nutr. 2019;122(3):282-290. PubMed
Pourmasoumi M, et al. Effect of Pycnogenol supplementation on blood pressure: a systematic review and meta-analysis. Phytother Res. 2019;33(1):253-262. PubMed
Belcaro G, et al. Pycnogenol in chronic venous insufficiency and related venous disorders. Phytother Res. 2019;33(10):2575-2580. PubMed
Belcaro G, et al. Improved cognitive function in healthy elderly with Pycnogenol. Panminerva Med. 2016;58(1 Suppl 1):1-7. PubMed
Luzzi R, et al. Pycnogenol supplementation improves cognitive function, attention and mental performance in students. Panminerva Med. 2011;53(3 Suppl 1):75-82. PubMed
Furumura M, et al. Oral administration of French maritime pine bark extract (Flavangenol) improves clinical symptoms in photoaged facial skin. Clin Interv Aging. 2012;7:275-86. PubMed
Marini A, et al. Pycnogenol effects on skin elasticity and hydration coincide with increased gene expressions of collagen type I and hyaluronic acid synthase in women. Skin Pharmacol Physiol. 2012;25(2):86-92. PubMed
Liu X, et al. French maritime pine bark extract Pycnogenol dose-dependently lowers glucose in type 2 diabetic patients. Diabetes Care. 2004;27(3):839. PubMed
Schönlau F, Rohdewald P. Pycnogenol for diabetic retinopathy. Int Ophthalmol. 2001;24(3):161-71. PubMed
Cisar P, et al. Effect of pine bark extract (Pycnogenol) on symptoms of knee osteoarthritis. Phytother Res. 2008;22(8):1087-92. PubMed