Effects of GRF (1-29) NH2 on short-term memory: neuroendocrine and neuropsychological assessment in healthy young subjects.
Alvarez. X A XA; Cacabelos. R R
Key Findings
- IV GRF‑1‑29 (150 µg) increased short‑term word recall after 2 hours versus placebo (14.8 ± 1.6 vs 11.8 ± 1.3 words).
- A second, unrelated word list was also remembered better after GRF (12.2 ± 1.7 words, p < 0.005).
- Subjects with higher basal GH had a larger GH surge after GRF, but memory improvement occurred regardless of baseline GH.
Practical Outcomes
- For biohackers interested in cognitive enhancement, a single 150 µg IV dose of GRF‑1‑29 may provide a modest short‑term memory boost within a few hours. The effect appears independent of baseline growth‑hormone levels, but the study used intravenous administration, so translating this to subcutaneous or oral routes is uncertain. More research is needed to confirm safety and optimal dosing before routine use.
Summary
A single IV dose of 150 µg GRF‑1‑29 (the short fragment of growth‑release‑factor) helped healthy young adults remember more words two hours later compared to a saline placebo. The memory boost was seen in both people with high and low natural growth‑hormone levels, though those with higher baseline GH showed a bigger hormone spike after the injection.
Abstract
Recent studies seem to indicate that the somatotropinergic system (STS) (GRF-SS-GH-SM axis) may be involved in the neuromodulation of higher activities of the central nervous system (CNS). In an attempt to demonstrate the influence of the STS on memory functions in humans, we have investigated the effects of acute administration of exogenous GRF vs. placebo on short-term memory (STM) in healthy young subjects. We gave GRF(1-29)NH2 (150 micrograms; i.v.) to a group of subjects (EG) (N = 17) and placebo (0.9% saline, 1 ml; i.v.) to a different group of subjects (CG) (N = 6). Prior to testing we presented a list of 20 neutral words (A1), and 2 hours after injection the same list (A2) and another list (B) of similar characteristics were presented in order to evaluate cognitive performance (CP). Basal CP (A1 list) was similar in EG and CG. Differences between EG and CG were found for both A2 (EG = 14.76 +/- 1.55 words vs. CG = 11.83 +/- 1.34 words, p less than 0.01) and B lists (EG = 12.17 +/- 1.68 words, p less than 0.005). According to the basal serum GH levels, EG subjects were divided into 2 subgroups: EG1 (N = 6), with high basal GH levels (11.57 +/- 4.47 ng/ml) and EG2 (N = 11), with low basal GH levels (1.55 +/- 1.71 ng/ml), similar to CG (1.3 +/- 1.53 ng/ml). GRF-induced GH response showed maxima 15 (28.15 +/- 11.71 ng/ml) and 30 min (28.09 +/- 17.07 ng/ml) after injection in EG1 and at 45 min (15.52 +/- 14.45 ng/ml) in EG2.(ABSTRACT TRUNCATED AT 250 WORDS)
Study Information
pubmed
1990