Supplement Evidence by Benefit

Evidence summaries powering the Common Sense Dog AI assistant, grouped by what each supplement supports. Confidence ratings reflect the strength of canine-specific research. Related: [[nutrition_reference]].

⚠️ Educational, not veterinary advice.

🦴 Joint Support — Green-Lipped Mussel

Perna canaliculus, a New Zealand shellfish; marine omega-3s + glycosaminoglycans that modulate the COX/LOX inflammatory pathways (inhibits PGE2, like a milder NSAID).

• Evidence: MEDIUM, mixed. Hielm-Björkman 2009 (n=45 RCT): beat placebo on pain/mobility over 8 wks — but less than carprofen. Corbee 2022 (n=32 crossover): improved over baseline but not vs placebo.
• Form matters — positive research used concentrated stabilized lipid extracts (PCSO-524, e.g. Antinol), not plain dried powder.
• Krill combo (EAB-277/Antinol Rapid) showed effectiveness in a blinded canine study; whether it beats GLM alone isn't established.
• Slow-acting (8–16 wks consistent use); generally well-tolerated; caution with shellfish sensitivity.

🔥 Anti-Inflammatory — Curcumin / Turmeric

Turmeric = the whole spice; curcumin/curcuminoids = the small active fraction. Research uses concentrated extracts, not kitchen turmeric.

• Evidence: LOW-to-MEDIUM. Comblain 2017 (n=42, 3-mo RCT): significant reduction in pain-on-manipulation, but flat objective gait (force-plate) measures.
• Mechanism: HIGH — downregulates TNF-α, NF-kB, IL-8, COX-2 (PTGS2) in cell/in-vivo studies.
• Bioavailability is the core problem — plain curcumin is poorly absorbed/rapidly cleared. Needs enhancement: phosphatidylcholine-bound, or piperine (black pepper) + fat. "Golden paste" is sound in principle but unvalidated in dogs and hard to standardize (LOW).
• Dose loosely 50–250 mg curcumin 3×/day (Wynn 2007); product curcuminoid content varies widely. Safe; watch blood-thinner interactions + GI upset at high doses.

🦠 Gut & Digestive — Fecal Microbiota Transplant (FMT)

Transfer of processed donor stool (enema or oral capsule) to correct dysbiosis (low gut bacterial diversity, measured via "dysbiosis index").

• Evidence: MEDIUM overall, stronger for acute disease. 2025 prospective (n=20 chronic enteropathy): clinical index 5→1 at 1 mo, 17/20 still improved at 3 mo, some stable to 1 yr; improved bile acids + propionate. But Toresson 2022 (n=13 IBD, blinded): FMT = placebo (both also on steroids + hypoallergenic diet → improvement likely from concurrent therapy).
• Best evidence in acute/infectious GI — parvo puppies (faster recovery, less hospitalization), superior to metronidazole at correcting post-diarrhea dysbiosis. Weaker/mixed for chronic IBD.
• No protocol standard yet; safe with rigorous donor screening; vet-supervised. Durability long-term under-studied.

🛡️ Immune & Gut — Bovine Colostrum

First milk after calving; rich in immunoglobulins (IgG), growth factors (IGF-1, TGF-β), antimicrobial proteins, proline-rich polypeptides (PRPs).

• Evidence: MEDIUM (note: industry-funded). Satyaraj 2013 (n=24, 40-wk RCT, Purina-funded): 0.1% spray-dried colostrum → stronger/longer vaccine antibody response, ↑ fecal IgA, ↑ gut microbiota diversity.
• Gut — ↑ fecal IgA + microbiota stability; improved stool quality in weaned puppies; growth factors support gut-lining repair. Oligosaccharides act as a prebiotic (feeds beneficial bacteria, complements probiotics).
• Immune — Igs survive gastric transit (powder/capsule); PRPs modulate immunity bidirectionally.
• Senior benefit is theoretical (key trial mean age 2.5 yr) → LOW-to-MEDIUM for that claim. Limits: modest samples, industry funding, much mechanism from pigs/humans. Watch dairy-intolerant dogs.

🧘 Calming / Anxiety — L-Theanine

Amino acid from green tea; promotes alpha brain-wave/calm-but-alert state via neurotransmitter influence. Non-sedating (key appeal — dog stays responsive, good for training through triggers).

• Evidence: LOW-to-MEDIUM. Pike 2015 (open-label, storm-sensitive): owners reported less drooling/pacing/panting/hiding. Michelazzi (n=20 noise-phobia, 63-day + behavioral therapy): significant behavior improvement — but no change in blood cortisol (mixed signal).
• Weak designs: mostly open-label, owner-rated (caregiver placebo effect), small n (~10–20), some manufacturer-funded.
• Best for situational/noise anxiety (storms, fireworks), not severe/generalized — and as part of a plan with behavioral training; melatonin can complement for nighttime. Sustained daily use (weeks / lead into anxiety season) beats single last-minute dose. Match dose to size (some chews underdose big dogs). Wide safety margin.