Gelatin

Gelatin is an anti-inflammatory protein derived from collagen-rich animal parts such as skin, bones, and connective tissue, which Ray Peat distinguished sharply from muscle meats due to its unique amino acid profile. 2 Unlike muscle meats, gelatin contains significantly less cysteine, methionine, and tryptophan—amino acids that Peat identified as having antithyroid and pro-inflammatory effects when consumed in excess. 2 Instead, gelatin provides a large amount of the protective amino acid glycine, which Peat considered to have drug-like stabilizing properties, acting as an inhibitory neurotransmitter that promotes the GABA system and opposes estrogen’s excitatory features. 2

Peat argued that gelatin’s therapeutic effects extend far beyond simply providing building blocks for joint cartilage, a common but mistaken nutritional assumption. 2 He observed that the relief of pain and inflammation from gelatin is often almost immediate, resembling the anti-inflammatory effect of cortisol or aspirin, rather than resulting from the slow process of tissue repair. 2 Glycine achieves this by suppressing the formation of inflammatory messengers such as tumor necrosis factor (TNF), interleukin-6 (IL-6), and serotonin, while also electrically stabilizing nerve cells through a mechanism described as a chloride current. 2 This nerve-stabilizing action is protective in conditions like epilepsy, multiple sclerosis, and stroke, and is important for regulating sleep, breathing, and heart rhythm. 3 Peat personally reported that taking several grams of gelatin before bedtime allowed him to sleep through the night without interruption for the first time in years, and he noted that friends and relatives recovered from long-standing arthritic and rheumatic pain within days of taking 10 to 15 grams daily. 2

Because gelatin lacks the tryptophan that can exacerbate muscle pain and is low in the cysteine that suppresses thyroid function, Peat recommended it as a safe protein that can be increased considerably without worrying about increasing inflammation. 3 He explained that all conditions involving excess prolactin, serotonin, and cortisol—including autism, premenstrual syndrome, Cushing's disease, and diabetes—should benefit from a reduced intake of tryptophan and the specifically anti-inflammatory amino acids in gelatin. 2 Peat viewed diabetes as fundamentally an inflammatory problem driven by the accumulation of polyunsaturated fats, and he believed gelatin’s anti-inflammatory effect could be therapeutic for the condition. 4 For adults, he suggested that a large part of the daily protein requirement could be met with gelatin, noting that older studies used 30 grams of glycine for muscular dystrophy and that a daily intake of 100 grams of gelatin would not be unreasonable for decreasing fatigue. 5 When consuming a large serving of meat, he advised taking 5 or 10 grams of gelatin at approximately the same time so that the amino acids enter the bloodstream in balance. 5

On practical use, Peat emphasized that gelatin must be thoroughly dissolved in hot water or milk until no granules remain to ensure easy digestion, and he considered it unusual for someone to be truly allergic to it, though some individuals might react more to pork gelatin than to beef. 3 He preferred whole gelatin over isolated glycine supplements due to potential contaminants in manufactured amino acids, and he noted that gelatin made from skin likely contains very little fluoride, as most fluoride in an animal is concentrated in the bones. 2 Danny Roddy has reiterated that gelatin’s high glycine content acts as an anesthetic and anti-inflammatory agent, opposing estrogen’s excitatory features and suppressing serotonin. 1 Peat also pointed out that reducing stress to increase the ratio of progesterone to estrogen helps reverse the aged state of collagen, positioning gelatin as part of a broader anti-stress physiological strategy. 6