Veterinarian here 👋 Your groomer is right, and the near-identical amazon fakes you're seeing are a real problem, so let me steer you straight. Most collagen fails for three reasons: it's only type I when dogs need types I, II and III; it's chew or powder so barely 20% absorbs — which is exactly why your groomer said liquid; and the dose is far too low to do anything. What works is liquid hydrolyz

Majority view

Evidence supports that different collagen types (I, II, III) play distinct roles in dogs’ tissues and that both hydrolyzed collagen peptides and undenatured type II collagen can benefit canine joint and connective tissue health, but there is no high‑quality evidence that dogs categorically “need” all three types together or that chews/powders only allow ~20% absorption while liquids reach dramatically higher levels.[2][5][12][20] Peer‑reviewed and review articles show hydrolyzed collagen and UC‑II are effective in osteoarthritic dogs, yet they do not specify that multi‑type formulations are required or that form (liquid vs powder/chew) is the determining factor, and reported absorption/bioavailability percentages largely come from marketing sources rather than controlled comparative pharmacokinetic studies.[6][7][15][20] Research and veterinary guides indicate effective doses for joint benefits in medium dogs are in the 2,500–3,500 mg/day range for hydrolyzed collagen or ~40 mg/day for UC‑II, so many low‑dose products may indeed be under‑dosed, but the broad marketing assertion that “most collagen fails” because it is type I only, non‑liquid, and only 20% absorbed is not directly supported by authoritative evidence.[5][14]

Credible dissent

Commercial pet‑supplement sites and some veterinary‑authored guides promote **hydrolyzed**, often **liquid**, multi‑type collagen as superior and sometimes claim higher bioavailability figures (e.g., 90–95% absorption for liquids), implying that powders/chews are significantly less effective.[1][4][5][8] Other reputable educational resources on canine collagen emphasize the importance of matching collagen type to the desired tissue effect (e.g., type II for joints, type I/III for skin and connective tissue) but do not state that all dogs universally require types I, II, and III together, nor that form (liquid vs powder) alone determines clinical efficacy or that chews/powders are limited to ~20% absorption.[2][3][12][14] Peer‑reviewed studies document benefits from **hydrolyzed collagen** and **UC‑II** at appropriate doses without requiring a specific liquid form or multi‑type blend, and they do not quantify comparative absorption rates between supplement forms, which contradicts or at least fails to support strong marketing claims about liquid superiority and the alleged failure of most other products.[6][7][15][20]