Does collagen help tendons heal?

The three stages, and where the collagen evidence sits in each

Does collagen help tendons heal is a question that gets a cleaner answer when the word heal is unpacked into the three stages a tendon actually passes through, because the collagen evidence, such as it is, belongs to one of them and the shelf's habit of saying heals as if it were a single event is what makes the honest answer hard to hear. The first stage is inflammatory and lasts days: after a tear, a strain or a surgical repair, blood and immune cells arrive, damaged tissue is cleared and the chemical signals that recruit the repair cells are released, a stage that is necessary, self-limiting and untouched by any collagen trial, since nothing swallowed changes the arrival of inflammatory cells and nobody has tested whether it should. The second stage is proliferative and lasts weeks: fibroblasts migrate into the site and lay down a provisional matrix that is disorganised, highly cellular, high in water and made mostly of type III collagen, the finer, faster collagen of healing tissue and blood vessels, a scar rather than a tendon, weak in tension and not yet aligned to anything. No collagen trial touches this stage either; the scar is laid down whatever the plate holds, provided protein and vitamin C are not deficient, and a reader eating normally is not deficient. The third stage is remodelling and lasts months to over a year: the type III collagen is gradually replaced by type I, the dense, rope-forming collagen that tendon is made of, the fibres align themselves along the direction of the load the tendon is asked to carry, cellularity and water fall, and the tissue approaches, without fully regaining, its original strength. This is the stage where the two pieces of collagen evidence sit. The marker trial, from the Baar group, gave 15g of gelatin with vitamin C an hour before a short bout of loading and measured a doubling of a blood marker of collagen synthesis compared with placebo, with engineered ligaments grown in the participants' serum showing more collagen and greater stiffness; the synthesis it measured is type I procollagen production, which is remodelling's work. The one small outcome trial, in Achilles tendinopathy, gave 2.5g of specific collagen peptides a day beside a calf-strengthening programme for six months and reported greater improvement in a tendon function and pain score and earlier return to running than the programme with placebo, around twenty participants and manufacturer-funded, again a result that lives in the months of remodelling under load and not in the days or weeks before it. Stage by stage the tally is nothing, nothing, and two small studies in the third, both of them beside loading.

Why the evidence lives where it does, what helps means, and the habit on its true terms

Why the evidence lives in the remodelling stage and nowhere else is the biology, and knowing it tells a reader exactly what collagen can and cannot do for a healing tendon. The cells that remodel a tendon are tenocytes, and they increase collagen synthesis in response to one signal, mechanical load: a loading session switches synthesis up with a peak around a day later, and unloading switches it down, which is why early controlled loading heals a tendon better than immobilisation and why loading programmes are the treatment of tendinopathy. The collagen protocol is designed to sit on that signal, timing a rise in blood amino acids and small collagen peptides, which peaks around an hour after a 15g dose, to coincide with the session that tells the tenocytes to build, the hypothesis being that substrate arriving while the cell is building raises what it builds; the marker trial supports the hypothesis at the level of a blood marker and the Achilles trial at the level of one small clinical outcome, and that is the entire supporting evidence, with no trial in tendon rupture or surgical repair, where the first two stages dominate and the surgeon's and physiotherapist's decisions are the whole of the treatment. So helps means: in tendinopathy, during the months of remodelling, as a substrate taken beside the loading session, a possible modest addition to a loading programme that is doing the healing, and it does not mean faster through the inflammatory days, faster through the proliferative weeks, or any effect at all in a tendon that is not being loaded, since the synthesis the collagen feeds is the synthesis the load switches on. The three sentences that follow are what an honest tendon page says: loading heals tendons and nothing shortens the stages; collagen with vitamin C an hour before loading has a marker trial and one small outcome trial beside it, in tendinopathy, as an adjunct; and no tendon claim is authorised for collagen in the UK, so any tub promising tendon repair is printing a sentence it does not hold. The protocol dose is 15g, which is powder territory, and a reader with a sore Achilles or patellar tendon who wants to run it does so beside a rehab programme a physiotherapist has built, taking the gelatin or hydrolysed collagen with vitamin C about an hour before the session. The habit dose sits elsewhere on the ruler and the worked example is honest about it: two capsules, 1200mg hydrolysed type 1 marine collagen with 12mg vitamin C plus zinc, 120 for £16.99 at 28p a day, lab tested and UK made, below the 2.5 to 15g research band, its one lawful line being vitamin C's contribution to normal collagen formation for the normal function of cartilage and bones, and no tendon sentence anywhere on it. Does collagen help tendons heal: in one of three stages, beside the load that does the healing, on the evidence of two small studies, and the stages themselves keep their own time.

What to check on the label