Low-dose growth hormone-releasing hormone tests: a dose-response study.
Spoudeas. H A HA; Winrow. A P AP; Hindmarsh. P C PC; Brook. C G CG
Key Findings
- 10 µg and 100 µg IV doses of sermorelin significantly raise serum GH, 1 µg does not
- Higher dose (100 µg) delays time to peak GH and slows the decline, extending the GH elevation
- GH levels remain significantly above baseline 2 h after a 100 µg dose, but not after lower doses
Practical Outcomes
- For DIY users, a modest dose (around 10 µg) may be sufficient to trigger a GH pulse, while larger doses could give a longer‑lasting effect but may not be necessary. Keep in mind the study used IV delivery in young men, so subcutaneous use and different populations may respond differently. Start low, monitor effects, and consider that higher doses add cost and potential side‑effects without clear extra benefit.
Summary
In a small study of 10 healthy men, giving the GHRH peptide (sermorelin) by IV injection showed that a 10‑µg dose already caused a clear growth‑hormone spike, while a 1‑µg dose did not. A 100‑µg dose produced a similar peak but kept hormone levels higher for a longer time, with the peak arriving later and GH staying elevated for up to two hours.
Abstract
We have evaluated parameters of the serum growth hormone (GH) concentration response to saline and 1-, 10- and 100-micrograms intravenous bolus doses of amide analogue of GH-releasing hormone (GHRH (1-29)NH2) given in random order to 10 adult male volunteers of median body weight 68 (60-90)kg. Compared with saline, both 10- and 100-micrograms GHRH(1-29)NH2 doses (but not 1 microgram) resulted in significant peak GH responses (means and 95% confidence intervals: 24.03 (11.22-51.29) vs 26.09 (16.40-41.50) mU/l, respectively). Although the average rate of serum GH rise was similar after both 10 micrograms (2.05 (1.13-2.97) mU.l-1.min-1) and 100 micrograms of GHRH(1-29)NH2 (1.52 (0.69-2.35) mU.l-1.min-1; ANOVA F = 0.93, p = 0.35), the average rate of serum GH decline after peak GH was slower after the higher dose (10 micrograms vs 100 micrograms: 0.65 (0.40-0.90) vs 0.37 (0.23-0.50) mU.l-1.min-1; ANOVA F = 5.14, p = 0.04), suggesting continued GH secretion. Increasing GHRH(1-29)NH2 doses delayed the time to peak GH (1 microgram: 7.00 (3.50-10.52) min; 10 micrograms: 15.80 (13.62-17.98) min; 100 micrograms: 24.80 (18.40-31.12) min) and serum GH levels were still elevated significantly 2 h after injection of 100 micrograms GHRH(1-29)NH2 compared with other doses (saline: 0.98 (0.48-2.04) mU/l; 1 microgram: 0.68 (0.48-0.93) mU/l; 10 micrograms: 1.07 (0.56-2.04) mU/l; 100 micrograms: 5.01 (2.34-10.86) mU/l; ANOVA F = 11.10, p < 0.001). In a second study we tested five adult male volunteers with lower doses (0.5-10 micrograms) of GHRH(1-29)NH2.(ABSTRACT TRUNCATED AT 250 WORDS)
Study Information
pubmed
1994
10.1530/eje.0.1310238