The most commonly reported effect in the first month is improved sleep quality — often the first thing users notice. Athletes and active users often report faster recovery from training, reduced joint soreness, and improved tendon resilience over time. IGF-1 accelerates cellular repair and collagen synthesis. Ipamorelin, timed pre-bed, enhances the GH pulse that accompanies deep sleep — and many users report noticeably deeper, more restorative sleep within 2–4 weeks. Instead of relying solely on diagrams or textbook descriptions, learners can observe real human tissues to better understand endocrine glands and muscle anatomy, and how these relate to functional changes over time. When this is accompanied by reduced thyroid hormone output, it may contribute to a lower basal metabolic rate, though many older adults maintain normal thyroid function. In older specimens, adrenal glands often show increased fibrous tissue and other structural changes. "The structure of the anterior pituitary gland changes as vascularization decreases and the connective tissue content increases with increasing age." – OpenStax Thus, a gap exists in the literature for human studies examining the role of anabolic hormones (testosterone and insulin-like growth factor 1) on the motor system with respect to declining muscle and physical function with aging. Further, to what we already showed i.e., testosterone increased IGF-1 gene expression during RET (Gharahdaghi et al., 2019), both testosterone and estrogen blunted IGF-I feedback-dependent inhibition of GH secretion (Veldhuis et al., 2004, 2005); and as it was reported in prepubertal boys, lead to increase in GH and then IGF-1 levels; which in turn exhibit the further and indirect anabolic links between androgens and muscle growth (Mauras et al., 2003). Herein, we present a perspective article on the effects of selected anabolic hormones on the motoric system form and function to raise awareness, and increase discussion, of the potential role that anabolic hormones may have on influencing muscle and physical function via their impact on the human nervous system. In phase with the declines in neuromuscular function is the decline in hormone levels with aging, particularly several circulating factors thought to have anabolic effects (e.g., steroid hormones, growth hormone, and IGF-1). Physical effort causes damage to muscle fibers, which begins a number of processes leading to the reconstruction of muscle fibers, among others, by stimulating an increase in the concentration of anabolic hormones such as testosterone, GH, and IGF-1. Understanding these factors can indirectly help maintain healthy testosterone levels. While it doesn’t directly trigger testosterone release, IGF-1 contributes to an environment conducive to healthy testosterone production. Understanding its functions is key to understanding its potential indirect impact on testosterone. Insulin-like Growth Factor 1 (IGF-1) is a hormone structurally similar to insulin. Thus, several pieces of evidence suggest IGF-1 regulates function of the motoric system elements by enhancing regeneration or increasing cell excitability by upregulating Ca2+ channels. Cell cultures of newborn mouse motor neurons also suggest that astrocytes can mediate IGF-1 effects on cell survival (Ang et al., 1992). The advantage of this approach is that you never have a period where you are running nothing. This maintains testosterone elevation through different mechanisms while giving enclomiphene receptors a break. A more sophisticated cycling approach that has gained traction in the natty plus community involves alternating enclomiphene with herbal testosterone boosters. During the off period, many users maintain a portion of their gains using natural testosterone boosting supplements, though testosterone does trend back toward baseline. The remaining reasons to consider cycling are receptor desensitization and cumulative side effect management. The dose-response curve flattens while the side effect curve steepens. Some natty plus practitioners have gone even lower, experimenting with 3mg or even alternate-day dosing at 6.25mg, and reporting noticeable effects on bloodwork. A study in the Journal of Sports Science and Medicine found that bovine colostrum supplementation increased serum IGF-1 in athletes over an 8-week period. Vitamin D acts as a hormone that modulates GH sensitivity in the liver — low vitamin D means less IGF-1 per unit of growth hormone released. Heavy compound movements (squats, deadlifts, presses) generate the largest systemic IGF-1 response due to the sheer volume of muscle tissue recruited.
