Testosterone and GLP-1: What Men Should Know

Last reviewed: May 17, 2026

Last updated: May 17, 2026

Written by: Jay Hastings, CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

GLP-1 medications can influence testosterone levels in men through weight loss, metabolic changes, and direct hormonal signaling. Understanding these interactions and establishing baseline hormone status before starting therapy helps providers tailor treatment safely.

Men considering GLP-1 therapy often wonder whether these medications will affect testosterone production, sexual function, or overall hormonal balance. PlexusDx supports personalized evaluation by integrating biomarker screening and genetic insights into a comprehensive provider conversation.

How GLP-1 Therapy May Influence Testosterone in Men

GLP-1 receptor agonists lower blood glucose and promote weight loss by slowing gastric emptying and increasing satiety signals. Weight reduction itself can normalize testosterone levels in men with obesity, since excess adipose tissue produces aromatase, which converts testosterone to estrogen.

Some research suggests GLP-1 medications may also directly influence hormone secretion through pathways in the hypothalamic-pituitary-gonadal axis. Clinical monitoring of testosterone during therapy helps distinguish weight-loss effects from direct medication effects on hormone production.

Baseline Testosterone and Metabolic Screening Before GLP-1 Therapy

Establishing baseline testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) before starting GLP-1 therapy provides critical context for monitoring. Men with pre-existing hypogonadism or metabolic syndrome benefit most from comprehensive hormonal assessment.

Biomarker	Why It Matters	When to Check
Total & Free Testosterone	Establishes baseline; detects pre-existing hypogonadism; monitors changes during therapy	Before GLP-1 initiation and every 3-6 months during therapy
LH & FSH	Indicates whether hypogonadism is primary (testicular) or secondary (pituitary); guides provider interpretation	Initial assessment if testosterone is low or declining
Estradiol	Tracks conversion of testosterone; elevated levels may indicate adipose-related aromatization	At baseline and during weight-loss phase if symptoms warrant
Fasting Glucose & HbA1c	Assesses metabolic status; GLP-1 benefit may improve insulin sensitivity and reduce diabetes risk	Before therapy and at standard diabetes monitoring intervals

Genetic Predispositions in Metabolic and Peptide Pathways

Genetic variants in the MC4R, FTO, GLP1R, and GIPR genes influence how individuals respond to appetite regulation, weight loss, and metabolic changes. These predispositions may also correlate with baseline metabolic hormone patterns, including testosterone.

PlexusDx Precision Peptide Genetic Test identifies variants in GIPR rs1800437, GLP1R rs6923761, FTO rs9939609, and MC4R rs17782313. Understanding these predispositions can support more informed discussions with providers about expected weight-loss patterns and hormonal monitoring needs.

Safety Considerations and Who Should Have Baseline Hormone Screening

Men with a history of hypogonadism, testosterone replacement therapy, prostate cancer, or pituitary disorders should undergo formal hormone assessment before starting GLP-1 therapy. Providers may need to adjust testosterone replacement dosing if weight loss occurs, since dose requirements often decrease.

Sexual dysfunction, fatigue, or mood changes during GLP-1 therapy warrant hormone re-testing to distinguish side effects from medication-related hormonal shifts. Qualified healthcare providers should interpret all hormone results in the context of clinical symptoms and weight-loss trajectory.

How PlexusDx Supports a More Personalized Approach

PlexusDx supports men considering GLP-1 therapy by recommending baseline hormone screening and genetic pathway assessment. These biomarkers may help provide context for how an individual's metabolic and hormonal systems are likely to respond to weight loss and GLP-1 signaling.

The Precision Peptide Genetic Test reveals predispositions in metabolic and appetite-regulation pathways (GIPR, GLP1R, FTO, MC4R variants) that may correlate with baseline metabolic hormone status and weight-loss responsiveness. This information should be interpreted with a qualified healthcare provider and does not predict exact medication response or guarantee outcomes.

By combining baseline biomarker screening, genetic pathway insights, and comprehensive provider evaluation, men can engage in more informed conversations about GLP-1 therapy, realistic hormone monitoring expectations, and personalized treatment adjustments. PlexusDx emphasizes that all medical decisions require qualified provider oversight.

How Your Genetics Influence GLP-1 Response

Not everyone responds to GLP-1 medications the same way. Genetic variants — including GIPR rs1800437, GLP1R rs6923761, FTO rs9939609, and MC4R rs17782313 — influence how your body processes these medications, how much weight you lose, and how you tolerate side effects. PlexusDx maps 14 pathways, 49 peptides, and 150+ genetic insights to match each patient to the right medication, dose, and lifestyle protocol for their biology. The PlexusDx Precision Peptide Genetic Test ($99 add-on after your first month, or $298 standalone) gives your provider precise insight into your peptide genetic predispositions before the first prescription is written.

Access Personalized GLP-1 Care Through PlexusDx

PlexusDx offers six prescription GLP-1 protocols to all 50 states — no membership, no insurance required, async intake or live consult. The Microdose Glp1 Protocol starts at $129/mo. Medications are dispensed from licensed 503A compounding pharmacies following strict quality and safety standards. Add a Precision Peptide Genetic Test for $99 to personalize your protocol from day one.