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Pycnogenol (Pine Bark Extract)

Pycnogenol is a patented French maritime pine bark extract with dozens of small trials spread thinly across a dozen unrelated conditions. A 2020 Cochrane review graded every single outcome as very low certainty and concluded no firm statement about efficacy or safety is possible.

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What the science says

  • No condition has evidence strong enough to draw a conclusion Limited evidence

    Cochrane reviewed 27 RCTs (1,641 participants) covering asthma, ADHD, cardiovascular risk factors, chronic venous insufficiency, diabetes, erectile dysfunction, female sexual dysfunction, osteoarthritis, osteopenia and traumatic brain injury. Most conditions had one or two studies with 40-70 participants each; 22 of 27 trials had unclear risk of bias. Every primary outcome was rated very low certainty, and the authors' conclusion was that "no definitive conclusions regarding the efficacy or safety of pine bark extract supplements are possible." The pattern — many tiny positive trials, no large confirmatory one — is the classic signature of an evidence base that has not been stress-tested.

  • Lipid effects are small and inconsistent Limited evidence

    A 2019 systematic review and meta-analysis of Pycnogenol trials on plasma lipids found changes that were modest and heterogeneous across studies typically enrolling 20-60 people for 4-12 weeks. Nothing here approaches the effect size of established lipid interventions, and the trials are too short to say anything about cardiovascular events.

  • The premium over generic proanthocyanidin extracts is not evidence-based Limited evidence

    Pycnogenol is standardized to 65-75% procyanidins — chemically close to grape seed extract, which costs a fraction as much. The price difference reflects a patent and a large, supplier-associated publication programme, not a demonstrated advantage: no head-to-head trial shows Pycnogenol outperforms generic pine bark or grape seed extract on any clinical outcome.

Dosage & safety

Studied doseTrials used 50-360 mg/day, most commonly 100-150 mg/day in two or three divided doses for 4-12 weeks. Because the trials are individually too small for dose-response analysis, no evidence-based effective dose exists.
SafetyShort-term tolerability is good: reported adverse events are mostly GI upset, dizziness, headache and occasional mouth ulcers. Trials ran 4 weeks to 6 months and largely failed to report serious adverse events systematically, so long-term safety is genuinely unknown. Proanthocyanidins have mild antiplatelet activity — caution with anticoagulants and antiplatelets, and stop 2 weeks before surgery. May lower blood glucose; monitor if you take diabetes medication. Manufacturers describe immune-stimulating effects, so caution is generally advised with immunosuppressants and autoimmune disease, though the human evidence is thin either way. Not established in pregnancy or breastfeeding. Not banned in sport.

How to take it

TimingSplit into two or three doses across the day.
With food?With food, which limits GI upset.
Worth knowingTrials ran 4 weeks to 6 months with no systematic reporting of serious adverse events, so treat long-term daily use as untested rather than proven safe.

Interactions

With medications

  • warfarin, DOACs, aspirin and clopidogrel

    Proanthocyanidins have mild antiplatelet activity that adds to bleeding risk. discuss with your prescriber and stop 2 weeks before surgery

  • insulin, sulfonylureas and other diabetes medication

    Pycnogenol may lower blood glucose and add to treatment. monitor glucose

  • immunosuppressants

    Immune-stimulating effects are claimed by manufacturers and could theoretically oppose immunosuppression. avoid without your specialist's agreement

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does Pycnogenol actually work?

The evidence for Pycnogenol is limited: a 2020 Cochrane review of 27 small trials across conditions from asthma to erectile dysfunction rated every outcome as very low certainty. The reviewers concluded no definitive statement about the efficacy or safety of pine bark extract is possible.

Is Pycnogenol better than grape seed extract?

No trial shows it. Pycnogenol is standardized to 65-75% procyanidins, chemically close to much cheaper grape seed extract, and no head-to-head study shows Pycnogenol outperforms generic pine bark or grape seed extract on any clinical outcome.

How much Pycnogenol per day?

Pycnogenol trials used 50-360 mg/day, most commonly 100-150 mg/day split into two or three doses with food for 4-12 weeks. Because the trials were too small for dose-response analysis, no evidence-based effective dose exists.

Is Pycnogenol safe with blood thinners?

Use caution: the proanthocyanidins in Pycnogenol have mild antiplatelet activity, so discuss it with your prescriber if you take warfarin, DOACs, aspirin or clopidogrel, and stop 2 weeks before surgery. Pycnogenol may also lower blood glucose, and its long-term safety is unknown.

Scientific references

Where to buy

Vitacost, Root2, Pycnogenol® Pine Bark Extract, 50 mg, 90 Capsules

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