Does collagen help cartilage?

Three cartilages: the glassy joint surface, the fibrous menisci, discs and labra, and the elastic ear, and what each can and cannot do

Does collagen help cartilage is a question with a word in it that names three different tissues, and the honest page asks which one before it answers anything, because a reader usually means one of the three, the shelf answers for all of them at once, and the evidence, such as it is, covers part of one. The first cartilage is hyaline or articular cartilage, the glassy, pearly cap a few millimetres thick on the ends of the bones inside a joint, the surface a knee, a hip, a shoulder or a finger joint actually moves on. It is built on type II collagen, a different collagen type from the type I of skin, tendon and bone, woven into a dense gel of proteoglycans whose charged chains draw water into the tissue and hold it under pressure, which is what lets the surface bear the loads of walking and running with less friction than ice on ice. It has no blood supply, being fed by the joint fluid pumped in and out of it under load, and its cells, the chondrocytes, sit locked in a matrix they cannot migrate through, so that an adult's articular cartilage does not regenerate a defect and fills a deep one at best with fibrocartilage, a scar-like tissue without the original's properties; it is the cartilage that wears in osteoarthritis, the cartilage the knee osteoarthritis trials of every supplement addressed, and the one a reader with a worn knee means, with the astronaut's and the runner's lesson that it reads load like bone on the regenerate knee cartilage page. The second cartilage is fibrocartilage, and it is the one most sports injuries involve. The menisci of the knee, the two crescents of tough cartilage between the thigh bone and the shin that spread load and steady the joint; the intervertebral discs of the spine, with their fibrous outer rings; the labra, the rims of cartilage that deepen the sockets of the hip and the shoulder and that tear in the hips of footballers and the shoulders of throwers; and the triangular fibrocartilage of the wrist, the disc on the little finger side that twisting under load tears. Fibrocartilage is built on type I collagen, the same type as tendon and eaten collagen, in dense fibrous bundles, and it has a blood supply only at its outer rim, the red zone of a meniscus, so that a tear at the rim can heal and be repaired with sutures while a tear in the inner white zone cannot heal and is trimmed, which is the distinction a knee surgeon makes on a scan and the reason two meniscal tears get two different operations. No oral collagen trial has ever measured a meniscus, a disc or a labrum, by symptom, by imaging or by anything else, and the knee sorted structure by structure, cartilage, meniscus, ligament and tendon, is on the collagen and knee repair page. The third cartilage is elastic cartilage, which forms the ear and the epiglottis and holds its shape through elastin fibres, and nobody asking whether collagen helps cartilage is asking about their ears, so the honest page names it only to complete the set. Three cartilages, then: a joint surface that does not regenerate, a fibrous shock absorber that heals at its rim, and an ear.

What collagen's evidence covers in each, the type I against type II curiosity and why it is not the problem, what helps each cartilage, and the worked example

Collagen's evidence covers part of the first cartilage and none of the second, and the honest page sizes it. In hyaline cartilage joints, the knee osteoarthritis trials gave around 10g of collagen hydrolysate a day for twelve to twenty-four weeks to people with knee pain and found a point or two less pain on questionnaires than placebo, a small and fairly consistent symptom result, with no change in cartilage thickness or joint space on the imaging and X-ray studies that have looked, and one small twenty-four week pilot reporting a contrast MRI glycosaminoglycan signal in some knee regions that nobody has replicated; the three claims that hide in the sentence, reaches, changes and repairs, are graded separately on the collagen repair knee cartilage page, and the honest summary is that collagen helps hyaline cartilage in the sense of comfort and not of tissue. In fibrocartilage the evidence is nothing: no trial has given collagen to people with a meniscal tear, a disc problem or a labral tear and measured anything, so a reader with one of those has a clinician's question about the tear's zone, its stability and whether it needs repair, trimming or rehabilitation, and a supplement bought for it has been bought on an analogy. The type I against type II curiosity deserves its sentence because the shelf plays it both ways. Eaten collagen, from hide or fish skin, is type I; articular cartilage is type II, and the shelf sells type II collagen for joints on the strength of the match, while the sceptic points out that type I cannot become type II. Both miss the biology: digestion strips every collagen type to the same amino acids and short peptides before anything reaches the blood, so the type of the collagen eaten tells a chondrocyte nothing, and the limit on helping cartilage is not a mismatch of types but the fact that cartilage, like every connective tissue, builds and maintains its matrix in response to the load its cells sense and not to the supply of amino acids a fed body already has in abundance; undenatured type II collagen at 40mg is a different product with a proposed immune mechanism and its own small trials, and is not an argument about supply either. What helps each cartilage is known and is not swallowed. For the hyaline joint surface, moderate cyclic load through walking and cycling, which raised cartilage composition on contrast MRI in the exercise trials and feeds a tissue with no blood supply; quadriceps and hip strength, which absorb load before it reaches the surface; body weight, at around four kilograms across the knee per kilogram carried; and never being unloaded for longer than an injury requires. For fibrocartilage, a diagnosis of the tear's zone, protection and rehabilitation for the tears that can heal or be lived with, and a surgeon for the ones that lock, catch or do not settle, with the strength around the joint as the long-term protection against the next tear. For both, the osteoarthritis guidance's first line is exercise, strength and weight, with supplements neither recommended nor prohibited, and collagen's point or two at 10g sits beside that programme as an adjunct for the first cartilage's comfort. The worked example is that adjunct at habit scale, stated on its true terms: two capsules, 1200mg hydrolysed type 1 marine collagen with 12mg vitamin C at 15% of its reference value plus zinc, 120 for £16.99 at 28p a day, lab tested and UK made, below the 10g dose of the knee trials, carrying vitamin C's collagen formation sentence for the normal function of cartilage, which is the register's maintenance sentence and the one lawful cartilage claim on any supplement, and no cartilage claim of its own. Does collagen help cartilage: the joint surface, in comfort, modestly, at powder doses; the menisci, discs and labra, not that anyone has measured; and the ear, nobody asked.

What to check on the label