There Are Only 3 Ways To Increase Your IGF-1 (How To Pick The Right One)

Your liver is the bridge between growth hormone and the effects you actually feel.

When growth hormone pulses out of your pituitary, it travels to the liver, binds to receptors there, and triggers the production of something called IGF-1, which stands for insulin-like growth factor 1 and is the molecule responsible for most of what people associate with growth hormone: muscle repair, fat metabolism, recovery, body composition changes. Growth hormone is the signal. IGF-1 is the action.

So when someone says they want to "raise their growth hormone," what they usually mean is they want more IGF-1 circulating in their blood. And there are exactly three ways to get there, each entering the system at a different point in that chain.

The first way is to push the pituitary harder. The compounds that do this are called GHRH analogs, which are molecules that mimic growth hormone releasing hormone, the signal your hypothalamus sends to tell the pituitary to pulse out growth hormone. Sermorelin, Tesamorelin, and CJC-1295 all work this way. They are not growth hormone. They are instructions to your own system to make more of it.

This distinction matters because your body is listening the entire time.

Your pituitary does not operate like a faucet you can open as far as you want. It operates more like a thermostat. As your IGF-1 climbs, the brain releases something called somatostatin, which is an inhibitory hormone that tells the pituitary to slow its pulses. The system is self-correcting. So no matter how aggressively you dose a GHRH analog, your body will blunt the response once IGF-1 reaches the ceiling it has decided is appropriate for you. This is why these compounds carry a relatively lower risk profile. The feedback loop is still intact and still working.

The clinical data on Tesamorelin specifically illustrates this well. In the Falutz et al. 2007 trial, 40 weeks of Tesamorelin in HIV patients with lipodystrophy reduced visceral adipose tissue by roughly 15 percent compared to placebo, and IGF-1 levels rose significantly but stayed within a physiologically plausible range. The body was being nudged, not overridden.

The second path skips the pituitary entirely by injecting pharmaceutical HGH directly. When you do this, the signal is no longer coming from inside the feedback loop. It is coming from outside it, which means the body's ceiling no longer applies in the same way. Your IGF-1 can climb higher than your pituitary alone would ever push it, and that is the entire point of this approach for people whose goals exceed what their natural system can produce.

But the body still responds to the change. Research from Rosenthal et al. in 1986 showed that exogenous growth hormone suppresses the pituitary's response to GHRH, meaning when you are injecting HGH, the signal your hypothalamus sends to release more is largely ignored. And Hashimoto et al. in 2000 confirmed that even a smaller isoform of exogenous GH was enough to suppress endogenous secretion in healthy men. The pituitary goes quiet when it detects enough GH circulating.

This is why stacking exogenous HGH with a GHRH analog like Tesamorelin or CJC-1295 does not add benefit. You are paying for a signal that the suppressed pituitary cannot act on. The money goes nowhere.

The third path removes the liver conversion step entirely. IGF-1 LR3 is a modified version of IGF-1 that you inject directly into circulation. Nothing has to be converted. Nothing has to be signaled. You are delivering the endpoint molecule straight to the receptors that use it.

This is what makes it both the most potent approach and the one that requires the most careful management. When IGF-1 is elevated continuously without the pulsatile variation that comes from natural GH rhythms, the receptors that respond to it begin to downregulate, which means they reduce their sensitivity to the signal as a protective mechanism. This is why IGF-1 LR3 is cycled in windows of six to eight weeks rather than used continuously. The Chapman et al. 1998 data supports the mechanism here, showing that elevated circulating IGF-1 suppresses pituitary GH release, and that the free fraction of IGF-1 specifically is what drives that suppression. Run it long enough without a break and you are diminishing the very response you are trying to generate.

One misconception worth addressing directly is the idea that Tesamorelin does something unique to visceral fat that other growth hormone compounds cannot do. The reason Tesamorelin became associated with visceral fat reduction is that the trials which established its clinical profile specifically measured that outcome in a population that had excess visceral fat. But the mechanism is not unique to Tesamorelin.

Growth hormone drives fat breakdown through what is called GH-mediated lipolysis, which is the process by which growth hormone activates hormone-sensitive lipase in fat cells, releasing stored fatty acids into circulation to be burned. The tissue that responds most strongly to this is visceral fat, because visceral adipose tissue has a higher density of growth hormone receptors than subcutaneous fat. So whether the growth hormone in your system came from a GHRH analog, pharmaceutical HGH, or your own pituitary responding normally, it is targeting the same depot by the same mechanism. The Johannsson et al. 1997 trial confirmed this directly, showing that GH treatment in abdominally obese men reduced abdominal fat mass, improved lipid profiles, and lowered diastolic blood pressure over six months. The compound was pharmaceutical HGH, not Tesamorelin, and the visceral fat responded.

What none of these compounds do is create a caloric deficit. GH-mediated lipolysis releases fatty acids, but those fatty acids have to be oxidized rather than re-esterified and put back into storage. That requires a metabolic environment where energy demand exceeds energy intake. Without that, the mechanism exists on paper but does not translate into body composition change.

The practical framework is simpler than the biochemistry makes it sound. If your goal is to restore GH output that has declined with age and support sleep quality, recovery, and modest fat metabolism without going outside your body's regulated range, a GHRH analog is the appropriate tool. If your goals require IGF-1 above what your natural ceiling allows and you are prepared for the cost and monitoring that requires, pharmaceutical HGH is the path. If you have a specific short window with a specific outcome in mind and you understand the receptor dynamics, IGF-1 LR3 is available, but it does not forgive inattention.

The reason people end up confused about these compounds is that they are marketed by outcome rather than explained by mechanism. Once you know where each one enters the chain, the categories stop overlapping and the decisions stop being complicated.

---

References

1. Falutz J, Allas S, Blot K, Potvin D, Kotler D, Somero M, Berger D, Brown S, Richmond G, Fessel J, Turner R, Grinspoon S. (2007). Metabolic effects of a growth hormone-releasing factor in patients with HIV. N Engl J Med 357(23):2359-70. DOI: 10.1056/NEJMoa072375
2. Stanley TL, Grinspoon SK. (2015). Effects of growth hormone-releasing hormone on visceral fat, metabolic, and cardiovascular indices in human studies. Growth Horm IGF Res 25(2):59-65. DOI: 10.1016/j.ghir.2014.12.005
3. Moller N, Jorgensen JO. (2009). Effects of growth hormone on glucose, lipid, and protein metabolism in human subjects. Endocr Rev 30(2):152-77. DOI: 10.1210/er.2008-0027
4. Hashimoto Y, Kamioka T, Hosaka M, Mabuchi K, Mizuchi A, Shimazaki Y, Tsunoo M, Tanaka T. (2000). Exogenous 20K growth hormone (GH) suppresses endogenous 22K GH secretion in normal men. J Clin Endocrinol Metab 85(2):601-6. DOI: 10.1210/jcem.85.2.6377
5. Rosenthal SM, Hulse JA, Kaplan SL, Grumbach MM. (1986). Exogenous growth hormone inhibits growth hormone-releasing factor-induced growth hormone secretion in normal men. J Clin Invest 77(1):176-83. DOI: 10.1172/JCI112273
6. Chapman IM, Hartman ML, Pieper KS, Skiles EH, Pezzoli SS, Hintz RL, Thorner MO. (1998). Recovery of growth hormone release from suppression by exogenous insulin-like growth factor I: evidence for a suppressive action of free rather than bound IGF-I. J Clin Endocrinol Metab 83(8):2836-42. DOI: 10.1210/jcem.83.8.5040
7. Johannsson G, Marin P, Lonn L, Ottosson M, Stenlof K, Bjorntorp P, Sjostrom L, Bengtsson BA. (1997). Growth hormone treatment of abdominally obese men reduces abdominal fat mass, improves glucose and lipoprotein metabolism, and reduces diastolic blood pressure. J Clin Endocrinol Metab 82(3):727-34. DOI: 10.1210/jcem.82.3.3809

---

Join the free community:
Men: Iron Forge Brotherhood
Women: Powerhouse Fitness