Fundamentals
Have you found yourself feeling a persistent weariness, a subtle shift in your energy, or perhaps a diminished sense of vitality that seems to defy simple explanations? Many individuals experience these quiet changes, often dismissing them as an inevitable part of aging or the demands of modern life.
Yet, these sensations are frequently signals from your body, indicating a deeper imbalance within its intricate communication systems. Your personal experience of these symptoms is a valid starting point for understanding how your biological systems function, and how they might be recalibrated for optimal well-being.
The human body operates as a sophisticated network, where various biological messengers orchestrate nearly every physiological process. Among these messengers, hormones and peptides stand out as fundamental regulators. Hormones, produced by endocrine glands, travel through the bloodstream to distant target cells, influencing metabolism, growth, mood, and reproductive function. Peptides, which are shorter chains of amino acids, act as signaling molecules, often working locally or in concert with hormones to fine-tune cellular responses.
Consider the endocrine system as a grand orchestra, where each hormone plays a specific instrument, contributing to the overall symphony of health. When one instrument is out of tune, or a section is missing, the entire performance suffers. Peptides, in this analogy, might be seen as the conductors or specialized soloists, capable of eliciting precise, targeted responses that enhance the performance of the hormonal sections. Their combined action allows for a more harmonious and robust physiological state.
Understanding your body’s internal signals is the first step toward reclaiming vitality and function.
The synergistic benefits of combining peptides with hormones arise from this complementary relationship. Hormones establish the broad physiological landscape, while peptides offer a more precise, often localized, or modulatory influence. This dual approach can address imbalances with greater specificity and efficiency than either class of compounds might achieve alone. For instance, a hormone might set a general metabolic rate, while a peptide could specifically enhance the sensitivity of cells to that hormone, thereby optimizing its effect.
This concept extends to various aspects of health, from metabolic regulation to tissue repair and even cognitive function. When the body’s natural production of certain hormones declines, or when cellular signaling pathways become less responsive, introducing targeted peptides alongside hormonal support can help restore a more youthful and efficient biological state. This approach moves beyond simple replacement, aiming for a recalibration of the entire system.
The interplay between these biochemical messengers is not merely additive; it is truly synergistic. This means the combined effect is greater than the sum of their individual contributions. A peptide might activate a receptor that makes a cell more receptive to a hormone, or it might regulate an enzyme that influences hormone synthesis or breakdown. This intricate dance ensures that the body’s systems communicate effectively, promoting a state of balance and resilience.
What Are Hormones and Peptides?
Hormones are chemical messengers secreted directly into the bloodstream by endocrine glands. They travel to target organs and tissues to exert their effects. Examples include testosterone, estrogen, progesterone, and growth hormone. These substances regulate a vast array of bodily functions, including metabolism, growth, reproduction, mood, and sleep cycles. A deficiency or excess of any hormone can lead to a cascade of symptoms that significantly impact daily life.
Peptides are short chains of amino acids, typically ranging from 2 to 50 amino acids in length. They are smaller than proteins and serve as signaling molecules within the body. Peptides can act as hormones themselves, or they can influence the production, release, or activity of other hormones. Their smaller size often allows them to interact with specific receptors with high precision, leading to targeted biological responses.
The distinction between hormones and peptides can sometimes blur, as some peptides function as hormones (e.g. insulin, a peptide hormone). The key lies in their role as biological communicators. They carry instructions from one part of the body to another, ensuring that cells and organs coordinate their activities for overall systemic health. When this communication falters, symptoms such as fatigue, weight changes, mood fluctuations, or diminished physical capacity can arise.
How Do Hormones and Peptides Interact?
The interaction between hormones and peptides is a sophisticated feedback system. Consider the hypothalamic-pituitary-gonadal (HPG) axis, a central regulatory pathway for reproductive and hormonal health. The hypothalamus releases gonadotropin-releasing hormone (GnRH), a peptide, which signals the pituitary gland to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which are also peptides. These pituitary hormones then stimulate the gonads (testes in men, ovaries in women) to produce steroid hormones like testosterone and estrogen.
This axis exemplifies how peptides initiate and regulate the production of key hormones. Disruptions at any point in this axis can lead to hormonal imbalances. For instance, a decline in GnRH signaling can result in reduced LH and FSH, subsequently lowering testosterone or estrogen levels. Introducing specific peptides can help restore this signaling, thereby supporting the body’s natural hormone production.
Another illustration of this interaction involves growth hormone. The pituitary gland produces growth hormone, a larger protein hormone, under the influence of growth hormone-releasing hormone (GHRH), a peptide from the hypothalamus, and ghrelin, another peptide. Peptides known as growth hormone secretagogues (GHSs) mimic ghrelin’s action, stimulating the release of growth hormone. This demonstrates how peptides can directly stimulate the release of other critical hormones, impacting processes like muscle growth, fat metabolism, and tissue repair.
The body’s internal regulatory systems are designed for balance. When age, stress, environmental factors, or lifestyle choices disrupt this balance, symptoms manifest. By understanding the fundamental roles of hormones and peptides, and how they work together, individuals can begin to appreciate the potential for targeted interventions to restore their body’s innate capacity for vitality. This foundational knowledge empowers a more informed approach to personal wellness.
Intermediate
As we move beyond the foundational understanding of hormones and peptides, the discussion shifts to the practical application of these insights within personalized wellness protocols. Many individuals experiencing symptoms such as persistent fatigue, changes in body composition, diminished libido, or cognitive fogginess often find that these issues are not isolated but rather interconnected manifestations of systemic imbalances. Addressing these concerns requires a clinically informed strategy that considers the body’s entire regulatory network.
The concept of hormonal optimization protocols involves more than simply replacing a deficient hormone. It centers on recalibrating the endocrine system to function at its best, often by supporting the body’s natural production mechanisms and ensuring optimal cellular responsiveness. When combined with specific peptides, these protocols can achieve a more comprehensive and sustained restoration of physiological balance.
Personalized wellness protocols combine scientific understanding with individual needs for optimal health.
Consider the body as a complex communication network, where hormones are the primary messages sent across long distances, and peptides are the specialized signals that fine-tune these messages or activate specific receivers. When the network experiences interference or weak signals, introducing both the main message (hormone) and the signal booster (peptide) can restore clear and effective communication. This approach aims to restore not just levels, but also the dynamic interplay that defines robust health.
Testosterone Replacement Therapy for Men
For men experiencing symptoms of low testosterone, often referred to as andropause or male hypogonadism, testosterone replacement therapy (TRT) can significantly improve quality of life. Symptoms may include reduced energy, decreased muscle mass, increased body fat, mood changes, and diminished sexual function. A standard protocol often involves weekly intramuscular injections of Testosterone Cypionate (typically 200mg/ml). This exogenous testosterone helps restore circulating levels to a healthy range.
However, introducing external testosterone can sometimes suppress the body’s natural production of testosterone by signaling the brain to reduce its output of LH and FSH. To mitigate this, and to support fertility, specific peptides and medications are often integrated into the protocol:
- Gonadorelin ∞ This synthetic peptide mimics the action of natural GnRH. Administered via subcutaneous injections, typically twice weekly, it stimulates the pituitary gland to release LH and FSH. This action helps maintain testicular function and endogenous testosterone production, preserving fertility for men who desire it.
- Anastrozole ∞ As an aromatase inhibitor, Anastrozole is an oral tablet, often taken twice weekly. Its purpose is to block the enzyme aromatase, which converts testosterone into estrogen. Maintaining an appropriate testosterone-to-estrogen balance is important to avoid potential side effects such as water retention or gynecomastia.
- Enclomiphene ∞ This selective estrogen receptor modulator (SERM) can be included to further support LH and FSH levels. It works by blocking estrogen receptors in the hypothalamus, which then signals the pituitary to increase gonadotropin release, thereby stimulating the testes to produce more testosterone naturally.
This comprehensive approach to male hormonal optimization recognizes that simply raising testosterone levels is often insufficient. A balanced hormonal environment, supported by both direct hormone replacement and peptide-mediated endogenous stimulation, yields superior outcomes.
Testosterone Replacement Therapy for Women
Women, too, can experience symptoms related to declining testosterone, particularly during peri-menopause and post-menopause. These symptoms might include persistent fatigue, low libido, mood fluctuations, and difficulty maintaining muscle tone. Hormonal balance for women is a delicate interplay of testosterone, estrogen, and progesterone.
Protocols for women often involve lower doses of testosterone compared to men, typically administered via subcutaneous injection of Testosterone Cypionate (e.g. 10 ∞ 20 units or 0.1 ∞ 0.2ml weekly). This method provides a steady delivery of the hormone.
Additionally, progesterone is a key component, prescribed based on menopausal status. Progesterone plays a vital role in uterine health, sleep quality, and mood regulation. For some women, pellet therapy offers a long-acting option for testosterone delivery. These small pellets, containing testosterone, are inserted subcutaneously, providing consistent hormone release over several months. When appropriate, Anastrozole may also be used in women, particularly those with concerns about estrogen dominance or specific medical histories, to manage estrogen levels.
The goal of female hormonal optimization is to restore a physiological balance that supports overall well-being, addressing symptoms while considering the interconnectedness of the various endocrine signals.
Post-TRT or Fertility-Stimulating Protocol for Men
For men who have discontinued TRT or are actively trying to conceive, a specialized protocol is employed to restore natural testosterone production and fertility. This protocol leverages the body’s own regulatory mechanisms:
- Gonadorelin ∞ As previously mentioned, this peptide stimulates LH and FSH release, directly supporting testicular function and spermatogenesis.
- Tamoxifen ∞ A SERM, Tamoxifen blocks estrogen receptors in the hypothalamus and pituitary, thereby reducing negative feedback and increasing LH and FSH secretion. This encourages the testes to produce more testosterone and sperm.
- Clomid (Clomiphene Citrate) ∞ Similar to Tamoxifen, Clomid is another SERM that promotes the release of gonadotropins, leading to increased endogenous testosterone production and improved sperm parameters.
- Anastrozole ∞ Optionally, Anastrozole may be included to manage estrogen levels during this period of hormonal recalibration, ensuring that rising testosterone does not lead to excessive estrogen conversion.
This protocol represents a strategic withdrawal from exogenous hormones, utilizing peptides and selective modulators to reactivate and optimize the body’s intrinsic hormonal machinery.
Growth Hormone Peptide Therapy
Growth hormone peptide therapy is gaining recognition among active adults and athletes seeking benefits such as improved body composition, enhanced recovery, better sleep, and anti-aging effects. These peptides do not directly introduce growth hormone but rather stimulate the body’s own pituitary gland to produce and release more of it. This approach often results in a more physiological release pattern of growth hormone, avoiding the supraphysiological spikes associated with exogenous growth hormone administration.
Key peptides in this category include:
- Sermorelin ∞ A synthetic analog of GHRH, Sermorelin stimulates the pituitary gland to release growth hormone in a pulsatile, natural manner. It is often used for its anti-aging properties, promoting lean muscle mass, reducing body fat, and improving sleep quality.
- Ipamorelin / CJC-1295 ∞ This combination is a powerful duo. CJC-1295 is a GHRH analog that has a longer half-life, providing a sustained release of GHRH. Ipamorelin is a selective growth hormone secretagogue that mimics ghrelin, stimulating growth hormone release without significantly impacting cortisol or prolactin levels, which can be a concern with other secretagogues. Their combined action leads to a robust and sustained increase in growth hormone and subsequently, insulin-like growth factor 1 (IGF-1), which mediates many of growth hormone’s anabolic effects.
- Tesamorelin ∞ Another GHRH analog, Tesamorelin is particularly noted for its ability to reduce visceral adipose tissue, the harmful fat surrounding organs. It also improves metabolic markers and can enhance cognitive function.
- Hexarelin ∞ A potent growth hormone secretagogue, Hexarelin is known for its ability to significantly increase growth hormone release. It also has cardioprotective properties.
- MK-677 (Ibutamoren) ∞ This is an orally active, non-peptide growth hormone secretagogue. It stimulates growth hormone release by mimicking ghrelin’s action on the pituitary gland. MK-677 can lead to sustained increases in growth hormone and IGF-1 levels, supporting muscle gain, fat loss, and improved sleep.
These peptides offer a sophisticated means of optimizing growth hormone pathways, providing a more natural and sustainable way to harness the benefits of this vital hormone.
Other Targeted Peptides
Beyond the broad categories, specific peptides address highly targeted concerns:
- PT-141 (Bremelanotide) ∞ This peptide is specifically used for sexual health, addressing low libido and sexual dysfunction in both men and women. Unlike traditional medications that primarily affect blood flow, PT-141 acts on the central nervous system by activating melanocortin receptors in the brain. This leads to increased sexual desire and arousal, offering a unique mechanism for individuals whose sexual concerns stem from neurological or psychological factors. It can also work synergistically with other sexual health medications.
- Pentadeca Arginate (PDA) ∞ A synthetic peptide derived from BPC-157, PDA is gaining recognition for its powerful regenerative and anti-inflammatory properties. It supports tissue repair, accelerates wound healing, and reduces inflammation. PDA is particularly relevant for individuals recovering from injuries, seeking faster post-surgical healing, or managing chronic inflammatory conditions. Its enhanced stability and bioavailability compared to its precursor make it a promising tool in regenerative medicine.
The strategic integration of these peptides alongside hormonal optimization protocols represents a sophisticated approach to personalized wellness. It acknowledges the body’s intricate signaling pathways, aiming to restore balance and function with precision and efficacy. This level of targeted intervention allows for a more complete and lasting improvement in overall health and vitality.
Academic
The exploration of synergistic benefits between peptides and hormones requires a deep dive into the underlying endocrinology, molecular biology, and systems physiology. The human body is not a collection of isolated systems; rather, it functions as an interconnected biological matrix, where signals from one pathway invariably influence others.
Understanding this intricate web is paramount for designing truly effective personalized wellness protocols. The combined application of peptides and hormones moves beyond simplistic replacement models, aiming for a recalibration of the entire neuroendocrine-metabolic axis.
Consider the complexity of the hypothalamic-pituitary-gonadal (HPG) axis, a prime example of a hierarchical control system. The hypothalamus, a central command center in the brain, secretes gonadotropin-releasing hormone (GnRH) in a pulsatile manner.
This decapeptide acts on specific receptors in the anterior pituitary gland, stimulating the synthesis and release of two glycoprotein hormones ∞ luteinizing hormone (LH) and follicle-stimulating hormone (FSH). These gonadotropins then travel to the gonads, where they regulate steroidogenesis and gametogenesis. In men, LH stimulates Leydig cells to produce testosterone, while FSH supports Sertoli cell function and spermatogenesis. In women, LH and FSH regulate ovarian follicular development, ovulation, and the production of estrogens and progesterone.
The body’s intricate signaling pathways demand a systems-based approach for true recalibration.
When exogenous testosterone is administered in male testosterone replacement therapy (TRT), a negative feedback loop is activated. Elevated circulating testosterone levels signal the hypothalamus to reduce GnRH secretion and the pituitary to decrease LH and FSH release. This suppression of endogenous gonadotropin production can lead to testicular atrophy and impaired spermatogenesis, a significant concern for men desiring to maintain fertility. This is where the synergistic application of peptides becomes critically important.
Recalibrating the HPG Axis with Peptides
The integration of Gonadorelin into TRT protocols exemplifies a sophisticated peptide-hormone synergy. Gonadorelin is a synthetic analog of GnRH. By administering Gonadorelin, typically via subcutaneous injection, the pulsatile stimulation of the pituitary is maintained, thereby preserving LH and FSH secretion.
This counteracts the suppressive effects of exogenous testosterone on the HPG axis, allowing for continued endogenous testosterone production and maintenance of testicular size and spermatogenic function. This strategy ensures that while supraphysiological levels of testosterone are not necessarily achieved, the physiological integrity of the HPG axis is preserved, which is a more holistic approach to hormonal health.
The use of selective estrogen receptor modulators (SERMs) such as Enclomiphene or Tamoxifen, and aromatase inhibitors (AIs) like Anastrozole, further refines this recalibration. Enclomiphene, for instance, acts as an estrogen receptor antagonist in the hypothalamus and pituitary. By blocking estrogen’s negative feedback at these sites, it prompts an increase in GnRH, LH, and FSH release, thereby stimulating testicular testosterone production.
This mechanism is particularly valuable for men with secondary hypogonadism who wish to avoid exogenous testosterone or preserve fertility. Anastrozole, by inhibiting the conversion of testosterone to estradiol, prevents excessive estrogenic effects that can arise from TRT, such as gynecomastia or water retention, thus optimizing the overall hormonal milieu.
The combined use of these agents with testosterone replacement creates a more balanced and physiological hormonal environment, minimizing side effects and supporting long-term endocrine health. This is a prime example of how peptides and related pharmacological agents can modulate hormonal pathways for superior clinical outcomes.
Growth Hormone Axis Optimization
Another critical area of peptide-hormone synergy lies within the growth hormone (GH) axis. Growth hormone, secreted by the anterior pituitary, is a key anabolic and metabolic hormone. Its release is tightly regulated by hypothalamic peptides ∞ growth hormone-releasing hormone (GHRH), which stimulates GH release, and somatostatin, which inhibits it. Additionally, ghrelin, a peptide produced primarily in the stomach, also stimulates GH release via the growth hormone secretagogue receptor (GHSR).
Traditional exogenous GH therapy can lead to supraphysiological spikes and potential desensitization of receptors. Peptides known as growth hormone secretagogues (GHSs) offer a more physiological approach by stimulating the body’s own GH production.
Consider the following mechanisms:
| Peptide | Mechanism of Action | Synergistic Effect with GH Axis |
|---|---|---|
| Sermorelin | GHRH analog; stimulates pituitary GHRH receptors. | Promotes pulsatile, physiological GH release, avoiding supraphysiological spikes. Enhances natural GH production. |
| CJC-1295 | Long-acting GHRH analog (DAC-GHRH). | Provides sustained GHRH receptor activation, leading to prolonged GH and IGF-1 elevation. Often combined with Ipamorelin for amplified effect. |
| Ipamorelin | Selective GHSR agonist (ghrelin mimetic). | Stimulates GH release without significantly affecting cortisol or prolactin. Works synergistically with GHRH analogs by acting on a different receptor pathway. |
| Tesamorelin | GHRH analog. | Specifically targets visceral fat reduction and improves metabolic markers, demonstrating a targeted metabolic synergy with GH. |
| Hexarelin | Potent GHSR agonist. | Strongly stimulates GH release; also exhibits cardioprotective properties, linking GH axis modulation to cardiovascular health. |
| MK-677 (Ibutamoren) | Non-peptide GHSR agonist. | Orally active, provides sustained GH and IGF-1 elevation, supporting anabolic processes and metabolic regulation. |
The combination of GHRH analogs (like Sermorelin or CJC-1295) with GHSR agonists (like Ipamorelin or Hexarelin) creates a powerful synergy. GHRH analogs increase the pool of GH available for release, while GHSR agonists enhance the pulsatile release of that GH.
This dual action often results in a more robust and sustained increase in circulating GH and insulin-like growth factor 1 (IGF-1), which mediates many of GH’s anabolic and metabolic effects. This approach supports lean body mass, fat metabolism, tissue repair, and overall cellular regeneration, all without directly administering exogenous GH.
Peptides for Targeted Systemic Recalibration
Beyond the major hormonal axes, peptides offer precise interventions for specific physiological challenges, often interacting with or complementing hormonal pathways.
Sexual Health and Neuroendocrine Signaling
PT-141 (Bremelanotide) represents a unique approach to sexual dysfunction. Unlike phosphodiesterase-5 (PDE5) inhibitors that primarily enhance peripheral blood flow, PT-141 acts centrally. It is a melanocortin receptor agonist, primarily targeting the MC3R and MC4R in the hypothalamus and spinal cord.
Activation of these receptors leads to the release of dopamine and other neurochemicals in brain regions associated with sexual desire and arousal. This central mechanism means PT-141 can address psychogenic or neurogenic components of sexual dysfunction, making it effective for individuals who do not respond to traditional vascular-acting medications. Its synergy with hormones lies in its ability to restore the neurological drive for sexual activity, which can be diminished by hormonal imbalances, thus completing the picture of sexual vitality.
Tissue Repair, Inflammation, and Metabolic Interplay
Pentadeca Arginate (PDA), a synthetic analog of BPC-157, illustrates peptide-mediated tissue regeneration and anti-inflammatory effects. PDA’s mechanism involves stimulating angiogenesis (new blood vessel formation), promoting fibroblast proliferation, and enhancing collagen synthesis, all critical for tissue repair. It also modulates inflammatory cytokines, reducing systemic inflammation.
While not a hormone, PDA’s actions significantly impact metabolic health and recovery, which are intrinsically linked to hormonal balance. Chronic inflammation can disrupt hormonal signaling, leading to insulin resistance and metabolic dysfunction. By mitigating inflammation and accelerating tissue healing, PDA indirectly supports a more balanced metabolic and endocrine environment, allowing hormones to function more effectively.
The arginate modification in PDA enhances its stability and bioavailability, allowing for more consistent therapeutic effects. Its role in promoting vascular endothelial cell growth through stimulation of the VEGFR2 receptor and activation of the nitric oxide signaling pathway highlights its deep molecular impact on healing and circulation. This demonstrates how a peptide can influence fundamental cellular processes that underpin overall physiological resilience, complementing the broader regulatory roles of hormones.
The synergistic application of peptides with hormones represents a sophisticated evolution in personalized wellness. It moves beyond addressing isolated symptoms, instead focusing on the intricate biological communication networks that govern health.
By leveraging the precise signaling capabilities of peptides to modulate, enhance, or restore hormonal pathways, clinicians can achieve a more profound and lasting recalibration of the body’s systems, ultimately leading to a more complete restoration of vitality and function. This approach demands a rigorous understanding of both endocrinology and peptide science, ensuring that interventions are not only effective but also aligned with the body’s inherent physiological intelligence.
References
- Glaser, R. & Glaser, W. (2019). Incidence of invasive breast cancer in women treated with testosterone implants ∞ a prospective 10-year cohort study. Journal of Clinical Oncology, 37(36), 3507-3515.
- Glaser, R. & Glaser, W. (2021). Breast Cancer Incidence Reduction in Women Treated with Subcutaneous Testosterone. Aging and Disease, 12(2), 524-531.
- Krzastek, S. C. et al. (2020). Testosterone restoration using enclomiphene citrate in men with secondary hypogonadism ∞ a pharmacodynamic and pharmacokinetic study. BJU International, 125(1), 146-154.
- Nassar, G. N. & Leslie, S. W. (2024). Physiology, Luteinizing Hormone. StatPearls Publishing.
- Pinchera, A. et al. (2019). Growth Hormone Secretagogues ∞ From Bench to Bedside. Frontiers in Endocrinology, 10, 87.
- Shao, W. & Jin, T. (2022). Hepatic hormone FGF21 and its analogues in clinical trials. Trends in Pharmacological Sciences, 43(2), 123-135.
- Sigalos, J. T. & Pastuszak, A. W. (2017). The Safety and Efficacy of Testosterone Replacement Therapy in the Aging Male. Current Urology Reports, 18(10), 72.
- Smith, R. G. et al. (2017). Growth hormone secretagogues ∞ an update on their clinical utility. Clinical Endocrinology, 86(3), 295-303.
- Swerdloff, R. S. & Wang, C. (2018). Testosterone Replacement Therapy for Male Hypogonadism ∞ An Update. Endocrine Reviews, 39(4), 535-553.
- Yuen, K. C. J. et al. (2019). Tesamorelin in the treatment of HIV-associated lipodystrophy. Expert Opinion on Pharmacotherapy, 20(1), 115-125.
Reflection
Having explored the intricate dance between peptides and hormones, you now possess a deeper understanding of your body’s remarkable capacity for self-regulation and restoration. This knowledge is not merely academic; it is a powerful tool for personal agency in your health journey.
The symptoms you experience are not random occurrences; they are coherent messages from a system seeking balance. Recognizing these signals and understanding the biological mechanisms behind them transforms a vague sense of unease into a clear path for proactive engagement.
Your path toward reclaiming vitality is uniquely yours, shaped by your individual biology, lifestyle, and aspirations. The information presented here serves as a guide, illuminating the possibilities that exist when science is applied with precision and empathy.
It invites you to consider how a personalized approach, one that honors the interconnectedness of your biological systems, can lead to a profound sense of well-being and sustained function. This journey is about more than just addressing symptoms; it is about optimizing your inherent physiological potential.
Glossary
tissue repair
growth hormone
pituitary gland
growth hormone secretagogues
personalized wellness protocols
hormonal optimization
testosterone replacement therapy
exogenous testosterone
endogenous testosterone production
testosterone production
growth hormone peptide therapy
growth hormone secretagogue
growth hormone release
ghrh analog
hormone secretagogue
melanocortin receptors
personalized wellness
testosterone replacement
hpg axis
aromatase inhibitors
hormone secretagogues
