Tyr-Ala-Hexarelin, a synthetic octapeptide, possesses the same endocrine activities of Hexarelin and GHRP-2 in humans.
Arvat. E E; Di Vito. L L; Lanfranco. F F; Broglio. F F; Giordano. R R; Benso. A A; Muccioli. G P GP; Deghenghi. R R; Ghigo. E E
Key Findings
- Tyr‑Ala‑HEX produces a strong GH surge comparable to Hexarelin and GHRP‑2 (Cmax ~64 µg/L).
- It similarly stimulates prolactin, ACTH, and cortisol, indicating broader endocrine activation.
- The timing (Tmax) and overall exposure (AUC) of hormone responses are alike across all three peptides.
Practical Outcomes
- For biohackers, Tyr‑Ala‑HEX could be considered an alternative GH‑secretagogue with potency similar to GHRP‑2, but the data are limited to IV administration in a tiny sample. More research is needed to define safe sub‑cutaneous dosing, frequency, and long‑term effects before it can be recommended for routine use.
Summary
In a small study of healthy volunteers, the synthetic octapeptide Tyr‑Ala‑HEX boosted growth hormone (GH) just as well as the known GH‑secretagogues Hexarelin and GHRP‑2, and it also raised prolactin, ACTH, and cortisol to similar levels. This shows Tyr‑Ala‑HEX works like the other peptides but the study used an IV dose (2 µg/kg) that isn’t typical for everyday use.
Abstract
Hexarelin (HEX) and GHRP-2 are two synthetic hexapeptides, superanalogs of GHRP-6, belonging to GH secretagogue (GHS) family. GHS act via specific receptors at both the pituitary and the hypothalamic level to stimulate GH release both in animals and in humans. However, GHS also possess significant PRL- and ACTH/cortisol-releasing activity. Tyr-Ala-HEX as well as Tyr-Ala-GHRP-6 are, in turn, synthetic octapeptides generally used to perform binding studies because of their easy iodination. However, their endocrine activities have never been studied in humans. To clarify the endocrine activities of Tyr-Ala-HEX, in 7 young adult volunteers we compared the effects of the maximal effective dose of HEX (2.0 microg/kg i.v.) or GHRP-2 (2.0 microg/kg i.v.) with the same one of Tyr-Ala-HEX on GH, PRL, ACTH and cortisol levels. Basal GH, PRL, ACTH and cortisol levels in all testing sessions were similar. The administration of placebo did not modify hormonal levels. HEX and GHRP-2 administration induced the well known strong GH response (Cmax, mean+/-SE: 77.3+/-6.0 and 74.1+/-12.1 microg/l; AUC, mean+/-SE: 2596.7+/-251.1 and 2480.0+/-343.6 microg*min/l). These responses were similar to that induced by Tyr-Ala-HEX (63.7+/-18.5 microg/l; 1986.6+/-622.4 microg*min/l). Moreover, HEX, GHRP-2 and Tyr-Ala-HEX had the same significant stimulatory effect on PRL (14.9+/-2.5, 12.3+/-2.0 and 10.0+/-1.5 microg/l; 497.8+/-61.8, 480.4+/-66.9 and 415.8+/-58.5 microg*min/l), ACTH (48.0+/-10.1, 51.4+/-10.6 and 44.9+/-12.2 pg/ml; 1531.6+/-235.7, 1586.7+/-277.0 and 1338.1+/-164.5 pg*min/ml) and cortisol (179.9+/-10.0, 181.2+/-14.1 and 149.7+/-20.1 microg/l; 8465.0+/-406.6, 8689.2+/-788.1 and 6295.2+/-797.0 microg*min/l). Also the mean Tmax of the endocrine responses to HEX, GHRP-2 and Tyr-Ala-HEX were similar. In conclusion, the present results demonstrate that in humans Tyr-Ala-HEX is a GH secretagogue as potent as HEX and GHRP-2, two GHRP-6 superanalogs. Tyr-Ala-HEX also shares with HEX and GHRP-2 the same PRL- ACTH- and cortisol-releasing activity.
Study Information
pubmed
1999
10.1007/bf03350886