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Timing is Everything: When is the Best Time to Take Sermorelin?

Timing is Everything: When is the Best Time to Take Sermorelin?

Sermorelin is a synthetic growth hormone secretagogue. It stimulates your body’s natural release of growth hormone, an important hormone that maintains muscle mass, promotes fat-burning, improves cardiovascular function and stamina, and shortens recovery time after exercise and injury throughout adulthood.

Unfortunately, growth hormone levels decline steadily after around age 30,1 leading many people to look for ways to restore them. A decline in growth hormone is thought to underlie many of the symptoms associated with the aging process, including reduced energy, slower metabolism, difficulty maintaining muscle mass, increased abdominal fat, poor sleep, prolonged recovery times, and cognitive changes.2

When should Sermorelin be injected?

Growth hormone (GH) is secreted in short bursts throughout the day, with the biggest pulses right before you go to sleep. Exercise, trauma, fasting, and illness can trigger these bursts of GH. Typically, more GH is produced within an hour of deep sleep.3

While the frequency of GH pulses does not change with aging, the amplitude of the pulses markedly declines, especially sleep-related GH pulses.4 This led researchers to consider ways to stimulate the pituitary to produce a larger growth hormone pulse, especially before sleep.

Growth hormone release is controlled by hormones and other mediators from the pituitary gland and the rest of the body. Hypothalamic growth hormone-releasing hormone stimulates growth hormone release, and somatostatin inhibits GH release. The stomach secretes ghrelin, which increases growth hormone release. Insulin-like growth factor-1 (IGF-1) mediates GH’s effects throughout the body.

Hormone/Factor2Effect on Growth Hormone Release
Growth hormone-releasing hormoneIncreases
Stress, amino acids, low blood sugarIncreases
Free fatty acidsDecreases
Insulin-like growth factor 1Decreases

Your body’s circadian rhythm is an internal clock that controls when hormones are released. The best time to take sermorelin is at night, because that is when the largest pulse of growth hormone is naturally secreted. You want to maximize the pulse of growth hormone. Since blood sugar levels and free fatty acids also impact GH release. Taking it on an empty stomach at night can help reduce this effect.

Why do you have to take Sermorelin at night?

You do not have to take sermorelin at night, but taking it at night is thought to give the best results because it mimics your body’s natural release of growth hormone. It can take several months of regular sermorelin use to achieve the maximum effect.

How well does Sermorelin work?

More than 2,000 studies have been published on the benefits of growth hormone replacement to reverse many of the effects of an age-related decline in growth hormone release.2

Research suggests that replacing growth hormone in healthy older adults can elevate levels of IGF-1 to the normal range for young adults. When participants in a clinical study took GHRH injections daily, alone or with a formal exercise program, their IGF-1 levels increased by 35%.4

When 89 older adults were injected with sermorelin acetate daily for six months, they experienced significant improvement on several cognitive assessments, including problem-solving, psychomotor processing speed, and working memory. They did not note changes in other cognitive functions.4

Sermorelin reaches peak concentrations in about 5 to 20 minutes, and it does not affect the release of other hormones such as prolactin, luteinizing hormone, follicle-stimulating hormone, insulin, cortisol, glucose, glucagon, or thyroid hormone.5 Another study indicated that the incidence of low thyroid hormone (hypothyroidism) was 6.5% in clinical trials. Untreated hypothyroidism can also impact how well sermorelin works.

There has been little additional research on sermorelin since 2008 because the manufacturer EMD Serono had supply issues obtaining the active ingredient. There were no reports of any safety or efficacy concerns.5

Do I have to take Sermorelin on an empty stomach?

Free fatty acids and changes in blood sugar levels can affect growth hormone release. Taking sermorelin on an empty stomach helps ensure that you receive the full benefit of the medication. For best results, take sermorelin before bedtime and resume normal mealtimes the next day.

A woman exercising

Final thoughts

Sermorelin was an FDA-approved medication marketed as Geref. The manufacturer discontinued the medication due to supply-chain issues and competition with growth hormone as a treatment for growth hormone deficiency in childhood. Interestingly, the reason sermorelin was not an optimal growth hormone deficiency treatment in childhood makes it optimal as a treatment for aging adults.

Sermorelin stimulates the natural release of growth hormone, a safer alternative than replacing GH in adults. Children with growth hormone deficiency cannot stimulate enough of their own growth hormone, which makes sermorelin less useful for this purpose.6

Preliminary results from studies conducted before 2008 indicate that sermorelin increases growth hormone levels, potentially reversing the signs of aging associated with growth hormone declines.

If you have questions about sermorelin, contact one of the treatment specialists at Invigor Medical.


While we strive to always provide accurate, current, and safe advice in all of our articles and guides, it’s important to stress that they are no substitute for medical advice from a doctor or healthcare provider. You should always consult a practicing professional who can diagnose your specific case.  The content we’ve included in this guide is merely meant to be informational and does not constitute medical advice. 


  1. Giustina A, Veldhuis JD. Pathophysiology of the neuroregulation of growth hormone secretion in experimental animals and the human. Endocr Rev. 1998 Dec;19(6):717-97. doi: 10.1210/edrv.19.6.0353. PMID: 9861545.
  2. Garcia JM, Merriam GR, Kargi AY. Growth Hormone in Aging. [Updated 2019 Oct 7]. In: Feingold KR, Anawalt B, Blackman MR, et al., editors. Endotext [Internet]. South Dartmouth (MA):, Inc.; 2000-. Available from:
  3. Salvatori R. Growth hormone and IGF-1. Rev Endocr Metab Disord. 2004 Mar;5(1):15-23. doi: 10.1023/B:REMD.0000016121.58762.6d. PMID: 14966386.
  4. Macario, E., 2008. Growth hormone (GH)-releasing hormone and GH secretagogues in normal aging: Fountain of Youth or Pool of Tantalus?. Clinical Interventions in Aging Volume 3, 121–129..
  5. Ishida, J., Saitoh, M., Ebner, N., Springer, J., Anker, S.D., Haehling, S., 2020. Growth hormone secretagogues: history, mechanism of action, and clinical development. JCSM Rapid Communications 3, 25–37..
  6. Walker R. F. (2006). Sermorelin: a better approach to management of adult-onset growth hormone insufficiency? Clinical interventions in aging, 1(4), 307–308.
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Published: Jun 6, 2023


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