Peptide Response Estimator

How this works

This tool estimates population-average IGF-1 trajectories for two growth hormone secretagogues used in clinical practice. It is not an individual prediction. Your actual response will differ based on age, pituitary reserve, body composition, sleep quality, and adherence to the prescribed regimen.

Sermorelin and tesamorelin stimulate pulsatile growth hormone release from the pituitary gland, which in turn raises circulating IGF-1. Unlike exogenous GH injection, these peptides preserve the hypothalamic feedback loop: the pituitary still regulates pulse amplitude and frequency, so supraphysiological IGF-1 levels are less likely than with direct GH administration.

Tesamorelin has the strongest evidence among GH secretagogues. It is FDA-approved for reduction of visceral adipose tissue in HIV-associated lipodystrophy, backed by Phase III data from 806 participants showing approximately 15 to 18% visceral fat reduction at 26 weeks and a mean IGF-1 increase of roughly 108 ng/mL. The confidence bands for tesamorelin are narrower because the trial data is robust.

Sermorelin evidence comes from smaller clinical studies and clinical experience. The confidence bands are intentionally wider to reflect this thinner evidence base. Response to sermorelin depends heavily on remaining pituitary reserve, which declines with age. Patients with significant age-related pituitary decline may see minimal IGF-1 movement regardless of dose.

The model uses an exponential approach to plateau, which approximates the observed pattern of rapid initial IGF-1 increase that gradually levels off. The steepest changes occur in the first 8 to 12 weeks, and the curve flattens by 20 to 26 weeks as IGF-1 nears its new steady state.

Why confidence bands instead of single numbers: individual variation in GH secretagogue response is significant. Age, sleep quality, body composition, and pituitary reserve all affect response magnitude. The shaded band shows the range most patients fall within, not a guarantee that you will land inside it. If your baseline IGF-1 is entered, the projection anchors to your starting value; if left blank, it uses a population average of 150 ng/mL.

References

Falutz J, Allas S, Blot K, et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. N Engl J Med. 2007;357(23):2359-2370.

Sigalos JT, Pastuszak AW, Allison A, et al. Growth hormone secretagogue treatment in hypogonadal men raises serum insulin-like growth factor-1 levels. Am J Mens Health. 2017;11(6):1752-1757.

Freda PU, et al. Reduced visceral adiposity and improved lipid profile in HIV-infected patients treated with tesamorelin. Obesity. 2016;24(6):1380-1388.

National Academies of Sciences, Engineering, and Medicine. The Clinical Utility of Compounded Bioidentical Hormone Therapy. Washington, DC: National Academies Press; 2020.