Porcine Skin Gelatin Hydrolysate Promotes Longitudinal Bone Growth in Adolescent Rats.
"Collagen hydrolysates (CHs) are mixtures of peptides obtained by partial hydrolysis of gelatin that are receiving scientific attention as potential oral supplements for the restoration of osteoarticular tissues. The aim of this study was to evaluate the effectiveness of CHs for promoting longitudinal bone growth in growing rats. An in vitro study was carried out in osteoblast-like MG63 cells and the most effective CH on bone formation was selected among 36 various CHs. An in vivo study confirmed the functional effects of a selected CH with molecular weight of <3 kDa on longitudinal bone growth. CHs dose-dependently promoted the longitudinal bone growth and height of the growth plate in adolescent male rats, whereas gelatin failed to affect longitudinal bone growth. Insulin-like growth factor-1 and bone morphogenetic protein-2 in the CH treated group were highly expressed in the growth plate."
"Collagen is the major constituent of the connective tissues in vertebrates, comprising 30% of total body protein. The denatured form of collagen is referred to as gelatin and is commonly used in foods, pharmaceuticals, cosmetics, and others. To increase the solubility of gelatin, partially hydrolyzed gelatin products have been prepared and are referred to as collagen hydrolysates (CHs)."
3-Week old male Sprague-Dawley rats were used.
"Longitudinal bone growth in normal adolescent male rats was 404.0±11.6 μm/day, and administration of 50 and 250 mg/kg gelatin failed to promote the longitudinal bone growth. However, treatment with 250 mg/kg of CH significantly increased the longitudinal bone growth exhibiting 468.4±27.4 μm/day."<-The dosage for the alfa vitamins collagen above is 1000mg. So maybe a human should actually take a larger dosage. 250mg/kg is actually pretty insane dosage in terms of cost but growth was over 25% more. That's 550mg/lb. So a 200lbs individual would have to take 100 pills a day. 50mg/kg still increased height just not statistically significantly.
Here's the growth plate under Collagen Hydrolysate(growth plate height was increased by 11%).

"CHs with molecular weights <3000 Da that is able to increase IGF-1 and BMP-2 protein expression in growth plate, and consequently promote longitudinal bone growth in growing rats."<-the molecular weight of the supplement above is not listed. Looking it up Collagen Hydrolysate has an average molecular weight of 2000-5000 Da so it's possible that the molecular weight here is over the threshold but humans may be able to tolerate the higher moleculate rate than rats.
Food consumption doesn't seem to be measured but gelatin could serve as sort of a control to that.
Biological effect of hydrolyzed collagen on bone metabolism
couldn't get full study
Hydrolyzed collagen tripeptide promotes longitudinal bone growth in childhood rats via increases in insulin-like growth factor-1 and bone morphogenetic proteins
“Previous studies have reported that collagen tripeptide (CTP) derived from collagen hydrolysate has various beneficial effects on health by protecting against skin aging and improving bone formation and cartilage regeneration. Collagen-Tripep20TM (CTP20), which is a low-molecular-weight CTP derived from fish skin, contains a bioactive CTP, Gly-Pro-Hyp >3.2% with a tripeptide content >20%. Herein, we investigated the osteogenic effects and mechanisms of CTP20 (<500 Da) on MG-63 osteoblast-like cells and SW1353 chondrocytes. And we measured promoting ratio of the longitudinal bone growth in childhood rats. First, CTP20 at 100 μg/mL elevated the proliferation (15.0% and 28.2%), alkaline phosphatase activity (29.3% and 32.0%), collagen synthesis (1.25- and 1.14-fold), and calcium deposition (1.18- and 1.15-fold) in MG-63 cells and SW1353, respectively. In addition, we found that CTP20 could promote the longitudinal growth and height of the growth plate of the tibia in childhood rats. CTP20 enhanced the protein expression of insulin-like growth factor-1 (IGF-1) in MG-63 and SW1353 cells, and in the growth plate of childhood rats, along with Janus Kinase 2, and signal transducer and activator of transcription 5 activation in MG-63 and SW1353 cells. CTP20 also elevated the expression levels of bone morphogenetic proteins (BMPs) in MG-63 and SW1353 cells and in the growth plates of childhood rats. These results indicate that CTP20 may promote the endochondral ossification and longitudinal bone growth, through enhancing of IGF-1 and BMPs.”<-ideally though we don’t want to enhance IGF-1 and BMP we want to stimulate growth via direct mechanism due to the collagen peptides otherwise it doesn’t look like they are worth it.
Here’s a study on human children:
