Disclaimer: The medications discussed in this article may include compounded preparations from a licensed 503A compounding pharmacy. Compounded medications have not been reviewed or approved by the FDA and are not the same as commercially available FDA-approved products. This content is for educational purposes only and does not constitute medical advice or establish a provider-patient relationship. Please consult a licensed healthcare provider for personalized clinical guidance.
I have had patients come in wanting testosterone replacement therapy who, six months on sermorelin, had testosterone levels that no longer warranted it. That is not the outcome I expected when I first started considering sermorelin as a first step for borderline cases. But it happened enough, and consistently enough, that it changed how I sequence hormonal evaluation in men with overlapping symptoms.
The question of whether sermorelin increases testosterone is one I hear regularly. The connection between the growth hormone axis and the testosterone axis is real, measurable, and grounded in specific molecular biology. It is also widely misunderstood.
Does Sermorelin Increase Testosterone? What Sermorelin Does and Does Not Do for Testosterone
Sermorelin does not directly stimulate testosterone production. It acts on the pituitary’s somatotroph cells to increase growth hormone secretion through the GHRH receptor pathway, which in turn raises IGF-1. There is no direct sermorelin receptor on the Leydig cells of the testes where testosterone is synthesized. Claims to the contrary simplify the endocrinology to the point of inaccuracy.
What sermorelin does do is support several of the upstream conditions that allow the hypothalamic-pituitary-gonadal axis to function well. Understanding why requires a brief account of how the testosterone axis actually works and where it is vulnerable to disruption.
The HPG Axis and Where It Breaks Down
Testosterone production follows a precise signaling chain. Gonadotropin-releasing hormone, or GnRH, is released in a pulsatile pattern from the hypothalamus, typically every 90 to 120 minutes. Each GnRH pulse reaches the anterior pituitary and stimulates the release of luteinizing hormone and follicle-stimulating hormone. LH travels through the bloodstream to the Leydig cells in the testes, where it binds to LH receptors and triggers the steroidogenic cascade. The first and rate-limiting step involves the steroidogenic acute regulatory protein, or StAR, which transports cholesterol across the inner mitochondrial membrane, making it available for enzymatic conversion to testosterone.
This is the distinction between secondary and primary hypogonadism that guides clinical decisions. In primary hypogonadism, the testes themselves are damaged or dysfunctional — LH is high because the pituitary is trying harder in response to low testosterone. In secondary hypogonadism, the testes are capable of producing testosterone but the upstream LH signal is insufficient. This is where sermorelin’s indirect pathway becomes relevant, because several of the mechanisms that suppress the GnRH-LH-testosterone axis are the same mechanisms that also suppress growth hormone secretion.
How Sleep Deprivation Disrupts Both Axes Simultaneously
The most direct connection between the GH axis and the testosterone axis runs through sleep architecture. Testosterone secretion follows a strong nocturnal pattern, with the largest pulses occurring during slow-wave sleep in the early part of the night. Growth hormone also reaches its daily peak during slow-wave sleep. These two anabolic hormones share the same sleep-dependent window. When slow-wave sleep is compressed by sleep deprivation, fragmented sleep, or age-related sleep architecture changes, both decline together.
The mechanism involves cortisol. Sleep deprivation elevates evening cortisol, and cortisol directly suppresses GnRH release from the hypothalamus. With GnRH reduced, the pulsatile LH signal that the Leydig cells depend on weakens. Fewer and smaller LH pulses mean less StAR protein expression and less testosterone synthesis. Cortisol also suppresses GH secretion at the pituitary level, which is why the two hormones fall together during sleep deprivation and can, in the right patients, recover together.
Research published in Neuroendocrinology by Steiger and colleagues demonstrated that pulsatile GHRH administration increased slow-wave sleep from 14.0 to 20.2 percent of total sleep time — a 44 percent relative increase — alongside elevated nocturnal GH secretion. (PubMed) Restoring slow-wave sleep architecture through GHRH signaling creates conditions under which nocturnal GnRH pulsatility and LH release can also recover.
IGF-1’s Supporting Role in Gonadal Function
There is an additional mechanism that connects sermorelin’s effects to testosterone production, operating through IGF-1 rather than sleep. IGF-1 receptors are expressed on Leydig cells, and IGF-1 acts as a permissive factor for LH-stimulated steroidogenesis. In the presence of adequate IGF-1, Leydig cells are more responsive to LH. When IGF-1 is severely suppressed — as it is in patients with significant GH axis decline — LH stimulation alone is insufficient to generate a full testosterone response.
This permissive effect means that raising IGF-1 through sermorelin therapy can improve the efficiency of whatever LH signal is already present. A retrospective review by Sigalos and Pastuszak published in Sexual Medicine Reviews found that men on growth hormone secretagogue therapy saw IGF-1 rise from a mean of 159.5 ng/mL to 239.0 ng/mL over a mean of 134 days — a 50 percent increase with statistical significance. (PubMed) In patients where low IGF-1 was contributing to gonadal underperformance, that magnitude of IGF-1 recovery has meaningful implications for testosterone production.
When Sermorelin Is Enough and When TRT Is Necessary
For a man in his mid-40s with total testosterone in the 350 to 450 ng/dL range, symptoms of fatigue, poor recovery, reduced libido, and early body composition changes, I now look closely at the full lab picture before recommending TRT. LH and FSH are essential. If LH is low or low-normal alongside low testosterone, the problem is upstream — secondary hypogonadism — and sermorelin is a rational first intervention. If LH is elevated, the testes are already being maximally stimulated and failing to respond — primary hypogonadism — and sermorelin will not help.
IGF-1 on baseline labs is equally important. When IGF-1 is low alongside borderline testosterone, I strongly consider sermorelin first. The two deficits often share the same root cause in disrupted nocturnal hormonal secretion, and addressing the GH axis frequently moves both IGF-1 and testosterone in the right direction over three to six months. Patients with testosterone below 300 ng/dL, confirmed primary hypogonadism, or significant symptomatic burden are generally not candidates to wait.
For a complete overview of what TRT involves and how our program is structured, see the TRT information page here. For an explanation of what to expect in the first months of TRT, see our blogs here.
When Combining Sermorelin and TRT Makes Clinical Sense
The combination of sermorelin and testosterone replacement is one I use regularly for patients already on TRT but experiencing a suboptimal response. TRT replaces testosterone but does not address the growth hormone axis. Many men on TRT still have low IGF-1, poor recovery, and persistent body composition challenges because GH decline with age is a separate biological process from testosterone deficiency.
Adding sermorelin to an established TRT protocol frequently produces results that neither therapy achieves alone. The Sigalos and Pastuszak data showing a 50 percent IGF-1 rise is relevant here — men on TRT who achieve meaningful IGF-1 elevation on top of adequate testosterone levels have both axes supported simultaneously. Lean mass response is more robust. Recovery improves further. Cognitive clarity and energy often reach a level that TRT alone did not produce. The two therapies operate on different receptor systems through different downstream pathways and do not conflict — they complement each other.
Precision Telemed’s Approach to Sequencing
At Precision Telemed, sermorelin is priced at $199.99 per month and TRT at $199 per month, both available in all 50 states through 503A compounding pharmacies. The async model supports staged decision-making well — patients can start on sermorelin, recheck labs at six to eight weeks, and make data-driven decisions about whether to add TRT at that point without waiting months for an in-person follow-up.
For a deep clinical look at how sermorelin dosing and titration work and what labs to monitor, see How I Dose Sermorelin for Body Composition.
FAQ
Q: Does sermorelin directly increase testosterone levels? No. Sermorelin does not act directly on testosterone production pathways. Its potential to support testosterone levels is indirect — through improved slow-wave sleep architecture that allows nocturnal GnRH and LH pulsatility to recover, reduced cortisol-mediated suppression of the HPG axis, and IGF-1-mediated enhancement of Leydig cell responsiveness to LH stimulation.
Q: How long does sermorelin take to affect testosterone levels? If sermorelin is going to affect testosterone indirectly, it typically does so over a three to six month window — consistent with the time needed for sleep architecture improvement, IGF-1 elevation, and cortisol normalization to translate into HPG axis recovery.
Q: Can sermorelin replace testosterone therapy? In some cases involving borderline low testosterone, secondary hypogonadism, and clear upstream contributing factors such as low IGF-1 and disrupted sleep, sermorelin may produce sufficient improvement to avoid TRT. In primary hypogonadism or significantly low testosterone with elevated LH, it cannot substitute for replacement therapy.
Q: What labs should be checked before deciding between sermorelin and TRT? At minimum: total testosterone, free testosterone, LH, FSH, IGF-1, and cortisol. LH and FSH distinguish primary from secondary hypogonadism. IGF-1 indicates whether the GH axis is a meaningful contributing factor. This lab picture is essential before making a clinical recommendation.
Q: Is it safe to take both sermorelin and testosterone at the same time? Yes. Many providers use this combination intentionally. Sermorelin addresses the GH axis via GHRH receptor signaling and IGF-1 elevation. TRT addresses the HPG axis by replacing circulating testosterone. They operate through different receptor systems and do not conflict.
Q: Will the body stop producing testosterone if TRT is started? Yes, to varying degrees. Exogenous testosterone suppresses GnRH pulsatility and LH secretion, which reduces endogenous Leydig cell stimulation. Patients for whom fertility preservation is a priority should discuss this with their provider before starting therapy so the protocol can be structured accordingly.
Q: Why would testosterone improve on sermorelin if sermorelin does not target testosterone directly? Because testosterone production depends on a functioning hormonal environment, not just on adequate LH stimulation alone. Sleep deprivation, elevated cortisol, and low IGF-1 all impair the system. Sermorelin addresses several of those upstream factors, and in patients where those factors are the primary driver of the decline, the testosterone axis recovers as a consequence of the broader hormonal environment improving.
References
- Steiger A et al. Nocturnal sleep EEG and secretion of GH and cortisol after administration of GHRH. Neuroendocrinology. 1992;56(4):566-573. PubMed
- Sigalos JT, Pastuszak AW. The Safety and Efficacy of Growth Hormone Secretagogues. Sex Med Rev. 2018;6(1):45-53. PubMed
To speak with one of our licensed providers about whether this is right for you, visit www.precisiontelemed.com.
This article is for educational purposes only and does not constitute medical advice or establish a provider-patient relationship. Compounded medications have not been reviewed by the FDA and are not the same as commercially available FDA-approved products. Please consult your healthcare provider.