Pyroglutamic acid improves the age associated memory impairment 

Pyroglutamic acid (PCA) was compared with placebo in a randomized, double blind trial for assessing its efficacy in treating memory deficits in 40 aged subjects. Twenty subjects were treated with PCA and 20 with placebo over a period of 60 d. Memory functions were evaluated at baseline and after 60 d of treatment by means of a battery made up of 6 memory tasks. The results suggest that PCA is effective in improving some verbal memory functions in subjects affected by age-related memory decline. 

References:

Grioli, S., Lomeo, C., Quattropani, M. C., Spignoli, G., & Villardita, C. (1990). Pyroglutamic acid improves the age associated memory impairment. Fundamental & clinical pharmacology, 4(2), 169–173. https://doi.org/10.1111/j.1472-8206.1990.tb00485.x