Neither has been compared head-to-head in a controlled tendon trial
Bischoff-Ferrari HA, Gngler S, Wieczorek M, Belsky DW, Ryan J, Kressig RW, Sthelin HB, Theiler R, Dawson-Hughes B, Rizzoli R, Vellas B, Rouch L, Guyonnet S, Egli A, Orav EJ, Willett W, Horvath S (2025) Individual and additive effects of vitamin D, omega-3 and exercise on DNA methylation clocks of biological aging in older adults from the DO-HEALTH trial
In 5xFAD mice, selective neuronal loss is found in cortical layer 5 (L5), without affecting the overall neuron number in the total frontal cortex and hippocampus, and this correlates with the reduced anxiety-like behavior (Vrkonyi et al., 2022)
However, no human studies have examined truly long-term use extending over years or decades
Alpha hydroxy acids like glycolic acid can also conflict with copper peptides