🩹 Heal an injury

What actually decides this outcome, in order of size

Healing rate is set by four things and only one of them is on a shelf. Ranked by how much of a timeline each one owns:

1. Which tissue, because vascularity sets a clock running from 2 weeks to 12 months. Muscle is richly perfused and heals in 2 to 6 weeks. Bone regenerates rather than scars and remodels over 12 months. Tendon midsubstance is hypovascular and heals over 3 to 12 months. Articular cartilage is avascular and aneural and largely does not heal at all. Matching the strategy to the tissue is the hub's own rule, and it is correct across all 5 pathways.
2. Mechanical signal, at the right dose and the right time, over 12 weeks. Connective tissue cells transduce strain into collagen synthesis, which is why a loading program is a treatment rather than a rehabilitation afterthought. In chronic Achilles tendinopathy, twelve weeks of heavy slow resistance and twelve weeks of eccentric loading both produced significant improvement, differing mainly in adherence, 92% against 78% Beyer 2015. In knee osteoarthritis, exercise across 54 trials reduced pain by 12 points out of 100 Fransen 2015.
3. Whether the inflammatory signal is being switched off at the cyclooxygenase step. Inflammation initiates repair: it recruits macrophages that clear debris and then switch phenotype to drive matrix synthesis. Suppressing that in the first 7 to 14 days is the one common intervention with a mechanistic case for making healing worse, and it is why Inflammation resolution (not suppression) exists as a separate pathway rather than as a synonym.
4. Substrate, with 1 genuinely obligate cofactor. Prolyl-4-hydroxylase requires ascorbate to keep its iron center reduced; without it, procollagen is under-hydroxylated, the triple helix is unstable at body temperature, and the tissue built is defective. That is the mechanism of scurvy, and it is the only step in collagen synthesis where a vitamin is not optional.
5. The systemic background, which changes the ceiling on all 5 pathways. Glycemia, smoking, sleep and protein intake alter healing rate across every tissue on this hub, and none of them appears on any of the five pathways below.

The order to run these in, and what has to be true first

Name the tissue, load it correctly, stop suppressing the signal, then supply the substrate. The peptides come after all 4 because they argue about the rate of a process the first 4 decide the existence of.

1. Route by tissue before buying anything, because the 5 pathways are not interchangeable. Tendon and ligament with a slow, poorly vascularized presentation go to Angiogenesis & cytoprotection. Skin, cartilage and matrix questions go to Collagen & matrix synthesis. Anything chronic and inflamed goes to Inflammation resolution (not suppression). Bone goes to Bone & fracture healing, which is the only pathway here with drugs that have fracture end points Neer 2001. The gut is a connective-tissue injury most people never file as one, which is Gut lining & mucosal repair.
2. Load it, and treat adherence as the variable, since 92% against 78% was the difference that mattered. Two protocols worked equally well in the randomized comparison and differed in whether people completed them Beyer 2015. The practical question is which program gets done for 12 weeks, not which one is theoretically optimal.
3. Supply the obligate cofactor with the substrate, and time it to within 60 minutes of loading. Vitamin C is the ascorbate for prolyl and lysyl hydroxylation; Collagen and Gelatin + Vitamin C supply the glycine and proline that make up a third of the polypeptide. The one genuinely evidence-based timing trick on this hub is taking that substrate 30 to 60 minutes before loading, so plasma amino acids peak while blood flow to the tissue is highest.
4. Then the resolution layer rather than the suppression layer, which is a lipoxygenase branch rather than a blocked one. Omega-3 (Fish Oil) supplies the EPA and DHA, SPMs (Pro-Resolving Mediators) are the specialized pro-resolving mediators made from them by lipoxygenases, and Curcumin sits alongside as a broader anti-inflammatory whose main practical problem is absorption.
5. Then the peptides, with 0 randomized human trials stated. BPC-157 (inj/oral) and TB-500 have a substantial preclinical record and no published randomized human trial in the injuries people buy them for Staresinic 2022. That is a real mechanistic case and an absent clinical one, and both halves belong in the decision.
6. L-Glutamine belongs to the gut half, where the enterocyte turns over every 3 to 5 days. It is the preferred fuel of the enterocyte, which is a specific claim about one tissue rather than a general repair claim, and it is why the same molecule appears on two pathways with two different arguments.
7. Teriparatide is the only agent on this hub with a randomized fracture end point, and it is a prescription anabolic rather than a supplement: 14% of women on placebo sustained a new vertebral fracture against 5% on 20 µg over a median 21 months Neer 2001.

What gets bought for this that cannot move it

Injecting growth factors into a hypovascular tendon was the most plausible idea in this whole area and it did not work. In 54 randomized patients, platelet-rich plasma produced a VISA-A improvement of 21.7 points against 20.5 with saline at 24 weeks, not significantly different, with both arms doing an eccentric program de Vos 2010. The program was doing the work in both groups, which is the most useful single result on this hub.

Rest is not a treatment for connective tissue and measurably behaves like the opposite of one. Immobilization reduces tendon stiffness and cross-sectional area and reduces bone mineral density at the unloaded site within 2 to 6 weeks. Protecting an injury from the strain that drives its repair is a mechanism for a slower recovery, not a conservative choice.

The category that fails structurally is anything passive, because no receptor reads it. Modalities, injections and supplements all share the same limitation: they do not supply a mechanical signal, and the mechanical signal is what the tissue actually reads. That is why every pathway underneath this hub is an adjunct to a loading program rather than an alternative to one.

And if the joint has been degenerating for 10 years rather than injured, this is the wrong hub. Pain from an arthritic joint is synovial and subchondral rather than a healing problem, and it is Synovial inflammation & pain and Cartilage matrix & joint substrate. A tendon that ruptured completely, a fracture that has not united at 6 months, or a joint that locks or gives way are surgical questions, and no page on this site should be the reason somebody delays asking one.

How you would know it was working, on a real read-out and a real timescale

Healing has no blood marker, so the honest read-out is a loading test with a small panel behind it. The prediction: load tolerance improves before pain does, and if pain improves while load tolerance does not, something analgesic happened rather than something structural.

• A standardized loading test at 0, 6 and 12 weeks. Repetitions to failure or time under load, plus pain during and 24 hours after. Twelve weeks is the interval both randomized tendon trials used Beyer 2015, and three weeks is too short to say anything.
• HbA1c (Hemoglobin A1c) once, because it changes the prognosis across every tissue here. Advanced glycation end-products accumulate on long-lived collagen and stiffen it, and a raised HbA1c reframes a slow-healing tendon as a metabolic finding.
• Vitamin D (25-Hydroxy) once, and again at 12 weeks if it was low. It is relevant to bone directly and to muscle function indirectly, and it is correctable inside 12 weeks.
• hs-CRP (High-Sensitivity C-Reactive Protein) at baseline, expected normal in a chronic tendinopathy. A raised value with pain at multiple tendon insertions is a systemic inflammatory question rather than an overuse one, and that distinction is worth one blood test.
• Comprehensive Metabolic Panel (CMP) and Ferritin once, on 1 draw. Albumin is a crude but real index of whether protein intake supports a construction project, and iron deficiency limits the oxygen delivery every repair process needs.

What will fool you. Both arms of a good tendon trial improve by around twenty points de Vos 2010, so an uncontrolled personal experiment will always look successful. Injuries are usually treated at their worst, which guarantees regression toward the mean over 4 to 8 weeks. And pain resolving under any analgesic effect removes the limiter on load at exactly the point the tissue is least able to take it.

Sources read for these sections

• Beyer R. Heavy Slow Resistance Versus Eccentric Training as Treatment for Achilles Tendinopathy: A Randomized Controlled Trial. American Journal of Sports Medicine 2015;43(7):1704-11 · PMID 26018970
• de Vos RJ. Platelet-rich plasma injection for chronic Achilles tendinopathy: a randomized controlled trial. JAMA 2010;303(2):144-9 · PMID 20068208
• Neer RM. Effect of parathyroid hormone (1-34) on fractures and bone mineral density in postmenopausal women with osteoporosis. New England Journal of Medicine 2001;344(19):1434-41 · PMID 11346808
• Staresinic M, et al. Stable Gastric Pentadecapeptide BPC 157 and Striated, Smooth, and Heart Muscle. Biomedicines 2022 · PMID 36551977
• Fransen M. Exercise for osteoarthritis of the knee: a Cochrane systematic review. British Journal of Sports Medicine 2015;49(24):1554-7 · PMID 26405113