Does collagen increase muscle growth?

The leucine arithmetic: the threshold, whey, and how much collagen it would take

Does collagen increase muscle growth is a question that can be settled with a calculator before any trial is read, and the honest page does the arithmetic first because a lifter who has done it once never needs to read a muscle claim on a collagen tub again. Muscle growth is driven by muscle protein synthesis, the building of new contractile protein in the fibres, and synthesis after a meal is switched on by one amino acid in particular, leucine, which acts as the signal that tells the muscle cell there is enough material arriving to build; the research puts the threshold for a full synthesis response in young adults at around two and a half to three grams of leucine in a single sitting, and higher, nearer three to four grams, in older adults whose muscle has become less responsive. The threshold is the whole question, because the amount of leucine a protein delivers depends on its leucine content, and proteins differ enormously. Whey protein is roughly eleven percent leucine by weight, the richest common source, so a standard 25g scoop delivers around 2.7g of leucine and clears the threshold in one glass, which is why whey is the reference protein in muscle research and why a scoop after training does what it does. Collagen is roughly three percent leucine by weight, among the poorest of all food proteins, because collagen's sequence is dominated by glycine, proline and hydroxyproline, the amino acids that let it form a triple helix, at the expense of the branched-chain amino acids muscle uses as signals. A 15g scoop of collagen, the largest dose anyone takes and the tendon protocol's dose, therefore delivers under half a gram of leucine, roughly a sixth of the threshold, and the arithmetic for clearing the threshold from collagen alone is simple and absurd: around a hundred grams of collagen in one sitting, four times any dose in any trial, four hundred calories of powder in a single glass, to deliver the leucine a 25g scoop of whey delivers in a hundred. Even that absurd dose would not sustain the synthesis it triggered, because synthesis needs all nine essential amino acids present to build protein and collagen contains no tryptophan at all, which is why it scores at or near zero on the protein quality scales and why a muscle cell handed collagen alone has a signal with nothing to build with. The arithmetic says collagen cannot increase muscle growth at any dose anyone takes, and the trials that have measured synthesis directly say the same: in the randomised comparisons that gave whey or collagen peptides and measured muscle protein synthesis, whey switched it on and collagen did not, at matched protein doses, in young and older adults alike.

The trials that seem to say otherwise, what they measured, and where collagen honestly sits

The trials that seem to say otherwise exist and the honest page reads them, because the shelf quotes them and a lifter will meet them. Three manufacturer-funded randomised trials gave 15g a day of collagen peptides or a placebo to people doing resistance training for twelve weeks, older men with sarcopenia, untrained and trained younger men, and found greater gains in fat-free mass and in some cases strength in the collagen group. Read for their design, they show something true and something else than the headline. The placebo was silica, a non-protein, so the comparison was fifteen extra grams of protein a day against none, in groups whose baseline protein intake was often below the research targets for lifters, and extra protein of any kind helps an under-fed trainee gain lean tissue; there was no whey arm in any of the three, so the trials cannot say that collagen did anything a complete protein would not have done better, and the one trial that did add a whey comparison found whey ahead. The outcome was fat-free mass by bioimpedance or absorptiometry, which includes water, glycogen, bone and connective tissue as well as muscle, and a protein that is a third glycine and feeds connective tissue could plausibly add fat-free mass that is not contractile muscle; no trial measured muscle fibre size or synthesis in those participants. So the fat-free mass trials show that protein beside training beats no protein beside training, and that is all. Where collagen honestly sits for a lifter is beside complete protein and never in its place: the protein target of 1.6 to 2.2g per kilogram is met from whey, dairy, eggs, meat, fish, soya or a complete plant blend, each meal clearing the leucine threshold, and collagen's grams are not counted towards it because they carry almost no leucine and no tryptophan; a lifter who takes collagen does so for collagen's own reasons, the skin trials at 2.5g and above, the joint trials at 5 to 10g, the tendon protocol at 15g with vitamin C an hour before loading, which is also the one place collagen might indirectly serve muscle, by supporting the connective tissue the muscle pulls through, a mechanism with a proteomic study behind it and no outcome. The worked example is the habit at its true scale: 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, 1.2g of collagen carrying around 36mg of leucine, roughly one eightieth of the threshold, counting for nothing towards a protein target and making no muscle claim, with the zinc contributing to normal protein synthesis as its lawful sentence. Does collagen increase muscle growth: no, by arithmetic before evidence, and the lifter who wants growth puts 25g of whey where the collagen was.

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