The relationship between testosterone therapy and cardiovascular risk in men is one of the most debated topics in men's health. Headlines have warned of increased heart attack risk, yet the research tells a more nuanced story. Age, pre-existing cardiovascular disease, oestrogen levels, dosage, and delivery method all appear to play significant roles. This article examines the key findings from a major insurance-data study, explores the clinical questions it raises, and explains what men and their doctors should consider before starting or continuing testosterone therapy.
By Dr. Allison Smith, ZRT Laboratory Sex Hormone Binding Globulin (SHBG) is one of the most overlooked variables in hormone health. It directly controls how much testosterone is biologically active in your body — yet it rarely appears on standard blood panels. Whether you're dealing with symptoms of low testosterone, androgen excess, or unexplained hormonal imbalance, understanding SHBG is essential to getting the full picture. What is SHBG? SHBG is a protein produced primarily in the liver that binds tightly to testosterone — and to a lesser degree, oestradiol (E2) and dihydrotestosterone (DHT) — and carries them through the bloodstream....
When it comes to topical testosterone therapy, more is not always better. Dr. Allison Smith of ZRT Laboratory explains the U-shaped curve phenomenon — where both too little and too much testosterone produce the same symptoms — and why starting at low doses and titrating carefully is essential. She also outlines the key markers to check when a man’s testosterone numbers look good on paper but his symptoms persist.
Single nucleotide variations (SNVs) in the enzymes that metabolise estrogen can significantly alter breast cancer risk — in some cases by as much as 12-fold when multiple variants combine. In this detailed scientific overview, Jillian Harrington PhD of ZRT Laboratory explains how variations in CYP11A1, CYP19A1 (aromatase), CYP1B1, COMT and MnSOD affect the estrogen metabolism pathway, why catechol estrogens are dangerous, and how methylation testing can reveal individual vulnerability.
Eating well and reducing stress but still can’t shift the weight? You’re not alone — and hormones are very likely involved. In this Q&A, Hormone Health Educator Candace Burch of ZRT Laboratory answers the most common questions from women struggling with hormone-related weight gain: from persistently high cortisol and adrenal fatigue, to BHRT monitoring, how long results take, and why testing is essential for getting the dose just right.
