HSA | FSA CARDS ARE NOW ACCEPTED

Last reviewed: May 12, 2026 Last updated: May 12, 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. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

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.

This article is part of the PlexusDx Education Hub — your resource for evidence-based guidance on hormones and fertility. Browse all Hormones & Fertility education

In genetic testing, a pathway is a cluster of genes that work together to regulate a specific biological process — analyzed as a connected system rather than as isolated variants. The PlexusDx Precision Peptide Genetic Test is built around 14 pathways, 49 peptides, and 150+ genetic insights, with each pathway capturing the genetic architecture of a major health domain. The Reproductive Health pathway is one of those 14 — and for men, its 6 insights cover the genetic variables that collectively determine how testosterone is made, bound, converted, sensed, and regulated. Understanding what those 6 insights are and how they work together is the foundation for understanding what genetic hormone testing actually reveals.

What Makes a "Pathway" Different From a Single Gene Test?

Most genetic health reporting stops at the individual gene level: one variant, one trait, one conclusion. The pathway approach is structurally different. Rather than asking "what does this one gene do?" it asks "how do the genes that regulate this biological system interact, and what does the pattern of variants across them reveal?"

This distinction matters enormously for hormones. A man's SHBG genetics determine how much free testosterone is available — but that free testosterone is immediately subject to CYP19A1 aromatization, SRD5A2 conversion to DHT, and AR receptor sensitivity at the cellular level. Each of those layers is genetically variable. Understanding any one of them without the others gives an incomplete picture. The pathway structure captures the interaction, not just the individual parts.

The Reproductive Health pathway in the Precision Peptide Genetic Test delivers exactly this: six insights that map the male hormone system from production through clearance, from bioavailability through receptor response, as a single connected analysis.

The Six Reproductive Health Insights — What Each One Measures

Insight 1 — SHBG: Free Testosterone Bioavailability
SHBG (sex hormone binding globulin) variants determine how much testosterone circulates free and bioavailable versus bound and inactive. This is the bioavailability gate — the filter through which all other androgen signaling downstream must pass. High-SHBG variants reduce the free testosterone fraction even when total testosterone is normal. SHBG Genetics: Why Your Free Testosterone Varies covers this insight in depth.

Insight 2 — CYP19A1: Estrogen Conversion Rate
CYP19A1 encodes aromatase, the enzyme that converts free testosterone to estradiol. CYP19A1 variants set the genetic rate at which testosterone substrate is routed toward estrogen production. This is the most direct genetic driver of the testosterone-to-estrogen ratio in men. CYP19A1 and Estrogen Conversion in Men covers this insight in depth.

Insight 3 — AR (CAG Repeats): Androgen Receptor Sensitivity
The AR gene's CAG repeat length governs how efficiently the androgen receptor translates a testosterone signal into cellular action. Longer repeats mean reduced transactivation efficiency; shorter repeats mean higher sensitivity. This is the cellular-level reading of the androgen signal — the endpoint that production and bioavailability are ultimately serving. Androgen Receptor CAG Repeats: Sensitivity Explained covers this insight in depth.

Insight 4 — SRD5A2: DHT Conversion and Potency
SRD5A2 encodes 5-alpha reductase, which converts testosterone to dihydrotestosterone (DHT). DHT binds the androgen receptor with approximately two to three times the affinity of testosterone. SRD5A2 variants determine what fraction of available testosterone is potentiated through DHT conversion versus remaining as testosterone — shaping the androgen signal profile at DHT-sensitive tissues. SRD5A2 and 5-Alpha Reductase Genetics covers this insight in depth.

Insight 5 — ESR1 / ESR2: Estrogen Receptor Sensitivity
ESR1 (estrogen receptor alpha) and ESR2 (estrogen receptor beta) variants determine how sensitively tissues respond to the estradiol that CYP19A1 produces. Receptor sensitivity is as genetically variable as production — two men with identical estradiol levels can experience the effects of that estrogen very differently at the tissue level depending on ESR1/ESR2 genetics.

Insight 6 — LHCGR / FSHR: HPTA Axis Responsiveness and Fertility
LHCGR (LH receptor) and FSHR (FSH receptor) variants determine how sensitively the testes respond to LH and FSH signaling from the pituitary. LHCGR sensitivity shapes how effectively the LH-stimulating pathway drives testicular testosterone production. FSHR sensitivity shapes spermatogenic output — directly relevant to fertility preservation on androgen protocols. HPTA Axis Genetics: LH, FSH, and Fertility Preservation covers this insight in depth.

Why These Six Work as a System

The 6 Reproductive Health insights form a coherent cascade — not a checklist. SHBG determines the free testosterone available as substrate. CYP19A1 and SRD5A2 then compete for that substrate, routing it toward estradiol or DHT respectively. AR receives whatever testosterone and DHT reach the receptor and converts those signals to cellular action. ESR1/ESR2 receives the estradiol the CYP19A1 step produced. LHCGR and FSHR govern the upstream pituitary-testicular axis that produced the testosterone in the first place.

Changing one variable changes the interpretation of all others. A high-SHBG man with low CYP19A1 activity has a different estrogen picture than a low-SHBG man with the same CYP19A1 variant — less free testosterone means less substrate for aromatization regardless of enzyme activity. AR CAG repeat length determines whether the free testosterone that does bypass SHBG produces a strong or weak androgen effect. This system-level reading is why the pathway structure exists and why the complete picture is covered in the Complete Guide to Genetic Men's Hormone Testing.

How the Reproductive Health Pathway Connects to the Other 13 Pathways

Reproductive Health doesn't operate in isolation within the 14-pathway panel. Its 6 insights intersect with at least four other pathways:

Muscle Growth (15 insights): Androgens are primary drivers of muscle protein synthesis and interact with IGF1 signaling and GHSR (growth hormone axis). Testosterone and DHT status, mapped by the Reproductive Health pathway, shapes the hormonal environment in which ACTN3, IGF1, and MSTN genetics express themselves.

Mood (8 insights): Testosterone and estradiol both modulate monoamine neurotransmitter systems including dopamine (DRD2) and serotonin. The COMT enzyme — which clears catecholamines and catechol estrogens — sits at the intersection of the Mood pathway and estrogen metabolism, connecting Reproductive Health to mood regulation through a shared enzymatic step.

Energy Metabolism (12 insights): Testosterone and DHEA influence metabolic rate, body composition, and mitochondrial function. The adrenal androgen pathway (CYP17A1, CYP11A1) covered in DHEA and Pregnenolone Pathway Genetics links Reproductive Health to Energy Metabolism through the shared steroid precursor cascade.

Sexual Health (6 insights): Androgen signaling (AR, testosterone) and HPTA function (LHCGR/FSHR) interact directly with nitric oxide production (eNOS) and melanocortin signaling in the Sexual Health pathway, creating cross-pathway dependencies between reproductive hormone status and sexual response function.

What the Reproductive Health Pathway Can and Cannot Tell You

The 6 Reproductive Health insights reveal the genetic architecture of your male hormone system — the enzymatic rates, binding capacities, receptor sensitivities, and axis responsiveness that operate as your biological baseline before protocols, supplements, lifestyle, or age-related changes layer on top. They do not measure current hormone levels; those require blood testing. They do not diagnose any condition. And they do not prescribe any protocol — those are clinical decisions made with a qualified healthcare provider.

What they deliver is the genetic map that makes everything else interpretable. Results are accessible through the secure PlexusDx Results Portal, generated from the Illumina Global Screening Array at CLIA-certified labs, covering 57 unique SNPs across 48 unique genes. The synthesis of how all 6 Reproductive Health insights explain androgen protocol variability is in Why TRT Works for Some Men and Not Others: The Genetic Answer.

The Precision Peptide Genetic Test analyzes how your genes influence hormone-related biological pathways. It does not recommend, prescribe, or determine which peptides you should use. Consult a qualified healthcare provider before beginning any peptide protocol.

Ready to see your complete Reproductive Health pathway profile? Take the Precision Peptide Genetic Test

Frequently Asked Questions About the Reproductive Health Pathway

How many insights does the Reproductive Health pathway contain?

The Reproductive Health pathway in the Precision Peptide Genetic Test delivers 6 insights — analyzing SHBG (free testosterone), CYP19A1 (aromatization), AR CAG repeats (receptor sensitivity), SRD5A2 (DHT conversion), and LHCGR/FSHR (HPTA axis and fertility). All 6 work as a connected system within 14 total pathways and 150+ genetic insights.

Is the Reproductive Health pathway only relevant for men?

No — the Reproductive Health pathway applies to both men and women. For men it maps androgen bioavailability, aromatization, receptor sensitivity, and HPTA function. For women, estrogen metabolism, methylation, and receptor genetics. The Precision Peptide Genetic Test analyzes 6 Reproductive Health insights as part of 14 pathways and 150+ genetic insights.

How does the Reproductive Health pathway connect to other pathways?

Reproductive Health genetics interact with several other panel pathways: Energy Metabolism (testosterone and DHEA influence energy), Mood (estrogen and androgen levels affect mood pathways), Muscle Growth (androgens drive IGF1 activity), and Longevity (hormonal signaling intersects with FOXO3). The Precision Peptide Genetic Test's 14-pathway structure maps all cross-pathway interactions as a connected system.

This article is part of the PlexusDx Education Hub. Browse all Hormones & Fertility education

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.