Cat's Claw

Direct antimicrobial activity (in vitro). Certain Uncaria extracts (notably a pentacyclic-alkaloid chemotype often sold as Samento) have been shown in laboratory (in-vitro) studies to kill or reduce Borrelia burgdorferi in its spirochetal form and—importantly—some non-growing forms including round bodies and biofilm-like colonies that are thought to contribute to persistent infection. These findings are laboratory (not clinical) results. MDPI Frontiers

Anti-inflammatory / immunomodulatory effects. Cat’s Claw extracts reduce inflammatory mediators (for example, they decrease NF-κB activity and IL-6 in preclinical models) and have documented immunomodulatory effects in animal and preclinical studies—mechanisms that could theoretically help with Lyme-related inflammation and some chronic symptoms. A recent systematic review/meta-analysis summarizes these in-vivo anti-inflammatory effects. Frontiers

Specific chemotype matters. Uncaria tomentosa exists in different chemical “chemotypes.” The pentacyclic oxindole alkaloid (POA) chemotype (TOA-free—marketed as “Samento” by some companies) is the one most commonly referenced for immune-stimulating and anti-Borrelia effects in the publications and practitioner reports. 

• 28-patient clinical cohort (TOA-free Uncaria protocol): In a prospective cohort published as a clinic report, patients began with detox/supportive measures and then started TOA-free Cat’s Claw in week 3 at 600 mg three times daily and increased by 600 mg/day to reach 5,400 mg/day (1,800 mg three times daily) by end of week 4. That 5,400 mg/day was continued for several weeks, then the dose was individualized (commonly 3,600–5,400 mg/day) over 6 months. Note: that study combined many other interventions (dietary/supplemental/detox measures), was small, and not randomized. Biologisch Medisch Centrum BMC
• Commercial Samento tinctures / manufacturer guidance: Liquid Samento tinctures (the commonly sold TOA-free product) often give gradual titration drop dosing (example: start very low and increase to an approximate therapeutic dose — manufacturer examples range up to tens of drops 2×/day). Product instructions vary by vendor; those are manufacturer directions rather than clinical trial standards. (See product pages / labels for exact drop counts and titration schemes.) Vital Nutritionals NutraMedix Deutschland GmbH
• Typical supplement capsule dosages (general cat’s claw products): Many generic cat’s-claw capsules (not Samento specifically) commonly cite ~250–350 mg once or twice daily for general anti-inflammatory or joint uses. These lower doses are far below the high extract amounts used in the clinic report above. ʻTypical’ doses vary between products and extracts. Healthline Drugs.com

Key practical notes about dosing and product choice

• If a clinician or practitioner considers Cat’s Claw for Lyme, they typically select a TOA-free / pentacyclic chemotype (Samento) product because the literature discussing anti-Borrelia activity focuses on that chemotype. MDPI
• Titration (start very low and gradually increase) is commonly used in practice to monitor tolerance and possible Herxheimer-type reactions (worsening symptoms as bacteria die). The high doses used in the 28-patient report (several grams/day) are much higher than consumer capsule doses. Biologisch Medisch Centrum BMC Vital Nutritionals

Laboratory (in vitro) studies

• In vitro anti-Borrelia screening (Frontiers / Feng et al., 2020): several botanical extracts—including Uncaria (Samento)—show activity against stationary-phase (persister) B. burgdorferi cultures, including effects on round bodies and biofilm-like aggregates. These are laboratory screens and do not prove clinical efficacy. Frontiers
• Herb–drug interaction and in vitro profile (Molecules, 2019): an in-vitro analysis of Samento (Uncaria tomentosa extract) and Banderol found anti-Borrelia activity and characterized potential interactions (e.g., modest CYP effects and transporter inhibition) — useful for safety/interaction considerations. MDPI

Clinical / human studies

• Prospective cohort (n≈28) reporting improvement with TOA-free Uncaria + multimodal protocol. The clinic report / PDF (often cited in complementary-medicine circles) describes a 26-week, non-randomized prospective cohort where patients receiving an alternative protocol including TOA-free Cat’s Claw reported substantially greater symptom improvements than a control group receiving antibiotics. Important limitations: small sample size, non-randomized, multiple simultaneous interventions (so the specific effect of Cat’s Claw alone cannot be isolated), and publication outside mainstream peer-reviewed journals. Use caution interpreting these results. Biologisch Medisch Centrum BMC
• No large randomized controlled trials showing Cat’s Claw cures Lyme. To date (as of the searches I ran), there are no large, high-quality randomized clinical trials that prove Cat’s Claw is an effective, stand-alone treatment for Lyme disease. Available human studies are either small, not randomized, or investigate other conditions (for example, inflammatory symptoms in other diseases). The in vitro and small clinical series are hypothesis-generating, not definitive proof. FrontiersBiologisch Medisch Centrum BMC

Systematic reviews / pharmacology reviews

• Systematic review of preclinical anti-inflammatory activity (Frontiers, 2024) — summarizes multiple animal and preclinical studies showing anti-inflammatory effects (IL-6 and NF-κB reductions). This supports a plausible mechanism for symptomatic benefit but is not direct Lyme clinical proof. Frontiers
• Component and review articles (MDPI review / other reviews) summarize antimicrobial potential of Uncaria constituents and point to in vitro synergy with antibiotics in some experiments. MDPI