What’s Actually Driving Your Testosterone Down?

Most cases of low testosterone in modern men are not a problem with the testes. The number is downstream of body composition, sleep, and energy availability. The wellness-clinic algorithm walks past every one of them. Jordan and Austin walk through what actually drives men’s testosterone down, the mechanisms behind it, and the modifiable levers that bring it back up. MOSH, the leptin and Kisspeptin pathway, the aromatase loop, the sleep apnea picture most clinics never ask about, the GLP-1 and weight-loss data on testosterone recovery, the low energy availability case that hits high-volume lifters harder than they realize, and the closing question of when a standard-dose TRT prescription actually functions as a PED. This is Episode 3 of our four-part Signal book launch series. Mark, the patient we have been threading from Episode 1, finally gets his diagnosis revealed. Timestamps 00:00 The 9x stat and Mark's diagnosis revealed 02:10 How body fat suppresses testosterone (MOSH) 07:26 Primary vs secondary causes, and Klinefelter 11:35 Leptin and the Kisspeptin pathway 14:38 Mark: the body-composition picture 16:10 The 40-inch-waist case 20:01 Weight loss, GLP-1s, and does Ozempic raise testosterone? 24:21 T4DM: adding testosterone to lifestyle 28:35 Sleep, OSA, and Mark's diagnosis 38:39 TRT in untreated sleep apnea 41:47 Can you train your testosterone down? (LEA / EHMC) 50:12 Replacement dose vs PED 55:47 Four takeaways 57:46 Episode 4 preview and book pre-order Resources mentioned: Signal book pre-order: https://barbellmedicine.com/signal Training Plateau Action Plan (free): https://www.barbellmedicine.com/train... Barbell Medicine programs and coaching: https://www.barbellmedicine.com/ Episode 1 (Is the Testosterone Crisis Real?):    • Is the Testosterone Crisis Real? A Physici...   Episode 2 (Is Your Testosterone Actually Low?    • Is Your Testosterone Actually Low? The 3 S...   Referenced studies: Wu F.C.W. et al. 2010. Identification of late-onset hypogonadism in middle-aged and elderly men (EMAS). N Engl J Med 363(2):123-135. https://pubmed.ncbi.nlm.nih.gov/20554... Travison T.G. et al. 2011. The natural history of symptomatic androgen deficiency in men. J Am Geriatr Soc. https://pubmed.ncbi.nlm.nih.gov/18454... Corona G. et al. 2013. Body weight loss reverts obesity-associated hypogonadotropic hypogonadism: systematic review and meta-analysis. Eur J Endocrinol 168(6):829-843. https://pubmed.ncbi.nlm.nih.gov/23482... Kounatidis D. et al. 2025. The impact of GLP-1 receptor agonists on erectile function. Biomolecules 15(9):1284. https://doi.org/10.3390/biom15091284 Grossmann M. et al. 2024. Testosterone treatment, weight loss, and health-related quality of life and psychosocial function in men: 2-year RCT (T4DM QoL arm). J Clin Endocrinol Metab 109(8):2019-2028. https://pubmed.ncbi.nlm.nih.gov/38311... Leproult R., Van Cauter E. 2011. Effect of 1 week of sleep restriction on testosterone levels in young healthy men. JAMA 305(21):2173-2174. https://pubmed.ncbi.nlm.nih.gov/21632... Penev P.D. 2007. Association between sleep and morning testosterone levels in older men. Sleep 30(4):427-432. https://pubmed.ncbi.nlm.nih.gov/17520... Wittert G. 2014. The relationship between sleep disorders and testosterone in men. Asian J Androl 16(2):262-265. https://pubmed.ncbi.nlm.nih.gov/24435... Alemany J.A. et al. 2008. Effects of dietary protein content on IGF-I, testosterone, and body composition during 8 days of severe energy deficit and arduous physical activity. J Appl Physiol 105(1):58-64. https://pubmed.ncbi.nlm.nih.gov/18450... Mountjoy M., Sundgot-Borgen J.K., Burke L.M. et al. 2018. IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update. Br J Sports Med 52:687-697. https://pubmed.ncbi.nlm.nih.gov/29773... Areta J.L. et al. 2021. Low energy availability: history, definition and evidence of its endocrine, metabolic and physiological effects in prospective studies in females and males. Eur J Appl Physiol 121(1):1-21. https://pubmed.ncbi.nlm.nih.gov/33095... Mäestu J. et al. 2010. Anabolic and catabolic hormones and energy balance of the male bodybuilders during the preparation for the competition. J Strength Cond Res 24(4):1074-1081. https://pubmed.ncbi.nlm.nih.gov/20300... Hooper D.R. et al. 2018. Treating exercise-associated low testosterone (EHMC). Phys Sportsmed 46(4):427-434. https://pubmed.ncbi.nlm.nih.gov/30074... Hackney A.C. 2020. Hypogonadism in exercising males: dysfunction or adaptive-regulatory adjustment? Front Endocrinol 11:11. https://pubmed.ncbi.nlm.nih.gov/32082...