Sermorelin: Appropriate Medical Use
Sermorelin is FDA-approved as a diagnostic agent for growth hormone deficiency and has demonstrated efficacy as a treatment for idiopathic growth hormone deficiency in prepubertal children, though it is not recommended as routine therapy since daily recombinant human growth hormone produces superior catch-up growth. 1, 2
Primary FDA-Approved Indication
Sermorelin (also known as GRF-(1-29)-NH2) is a 29 amino acid synthetic analogue of human growth hormone-releasing hormone (GHRH) that specifically stimulates growth hormone secretion from the anterior pituitary. 1
Diagnostic Use
- Intravenous sermorelin at 1 mcg/kg bodyweight provides a rapid and relatively specific test for diagnosing growth hormone deficiency in children. 1
- This diagnostic test produces fewer false positive growth hormone responses compared to other provocative tests. 1
- Important caveat: Normal growth hormone responses to intravenous sermorelin cannot exclude growth hormone deficiency due to hypothalamic deficits; subnormal responses to other provocative tests are needed to confirm disease in these patients. 1
Therapeutic Applications
Growth Hormone Deficiency in Children
Subcutaneous sermorelin 30 mcg/kg bodyweight given once daily at bedtime is effective in treating some prepubertal children with idiopathic growth hormone deficiency. 1
Treatment Response Profile
- Significant increases in height velocity are sustained during 12 months of treatment, with limited data suggesting effects may be maintained for 36 months. 1
- Sermorelin induces catch-up growth in the majority of growth hormone-deficient children, with slow-growing, shorter children who have delayed bone and height age appearing to have the best response. 1
Critical Limitation
When treatment was changed from GHRH to recombinant human growth hormone (rhGH) at 2 U/m² daily given subcutaneously at bedtime, growth rate improved in all patients to a mean of 8.5 cm/year (range 6.2-14.6 cm/year), whereas GHRH therapy failed to produce catch-up growth in most patients. 2
Therefore, GHRH cannot be recommended for routine therapy of children with growth hormone deficiency since a single daily dose of rhGH produces superior catch-up growth. 2
Off-Label Use in Hypogonadal Men
In a retrospective study of 14 compliant men on testosterone therapy, combination therapy with 100 mcg each of GHRP-6, GHRP-2, and sermorelin administered three times daily significantly increased serum IGF-1 levels from a baseline of 159.5 ng/mL to 239.0 ng/mL (p < 0.0001) over a mean treatment duration of 134 days. 3
- Strict compliance with thrice-daily dosing is essential for efficacy. 3
- Concurrent use of aromatase inhibitors or tamoxifen resulted in smaller increases in IGF-1 levels, suggesting estrogen modulation may interfere with treatment response. 3
Dosing Specifications
Diagnostic Testing
- Administer 1 mcg/kg bodyweight intravenously as a single dose. 1
Therapeutic Use in Children
- Administer 30 mcg/kg bodyweight subcutaneously once daily at bedtime. 1
Off-Label Adult Use
- Administer 100 mcg subcutaneously three times daily in combination with other growth hormone secretagogues. 3
Safety Profile
Intravenous single-dose and repeated once-daily subcutaneous doses of sermorelin are well tolerated. 1
Common Adverse Events
Pharmacokinetic Limitations
The main drawback of sermorelin relates to its short half-life in plasma (approximately 10-20 minutes in humans), caused primarily by renal ultrafiltration and enzymatic degradation at the N-terminus. 4
Pregnancy Considerations
Sermorelin administered to pregnant women at term (mean 20 minutes before cesarean section) elicited only a small rise in maternal growth hormone levels (p = 0.08) and did not affect placental growth hormone secretion. 5
Sermorelin concentrations were undetectable in cord serum despite being readily detectable in maternal serum, indicating lack of transplacental passage and no effect on fetal growth hormone secretion. 5
Clinical Decision Algorithm
For diagnostic evaluation of suspected growth hormone deficiency: Use intravenous sermorelin 1 mcg/kg as part of a comprehensive provocative testing panel, not as a standalone test. 1
For treatment of confirmed idiopathic growth hormone deficiency in prepubertal children: Prioritize recombinant human growth hormone over sermorelin due to superior efficacy in producing catch-up growth. 2
Consider sermorelin only if recombinant human growth hormone is contraindicated, unavailable, or refused, using 30 mcg/kg subcutaneously at bedtime. 1
For off-label use in adults seeking increased lean body mass: Recognize this requires strict thrice-daily dosing compliance and lacks robust evidence for morbidity or mortality benefits. 3