TestoExperts is a reference on testosterone, testosterone deficiency and testosterone replacement therapy, written for men who want to understand their own situation rather than be sold a solution to it.
Who writes this
Darius A. Schneider, MD, PhD is an endocrinologist practising at Diabetes and Endocrine Specialists Medical Group, with offices in La Jolla, Poway and La Mesa. Low testosterone, testosterone replacement, male infertility and gynecomastia are part of the practice's men's health service line.
TestoExperts sits in the same network asdiaendo.com,sandiendo.com,hashiexperts.com,menoexperts.com andendotrials.org.
What we sell
Nothing. This site sells no supplements, no testosterone, no programmes and no memberships. It accepts no supplement advertising and no industry funding, and it takes no commission on anything it mentions.
That is worth stating plainly because it is unusual. Most of the testosterone information a man encounters online is published by a business that profits when he starts treatment. Those businesses are structurally unable to tell him he might not need it. We can.
How the evidence is handled
Sources are weighted in a fixed order: current professional guidelines and society statements, then systematic reviews and meta-analyses, then randomized controlled trials, then large prospective cohorts, then high-quality observational studies. Mechanistic research is used to explain, never to support a clinical claim on its own.
Testimonials, uncontrolled case series presented as efficacy, animal studies extrapolated to humans, influencer claims and supplement marketing are not treated as clinical evidence at any level.
Commercial testosterone platforms are read to understand what patients are being told and which claims need addressing. They are never cited as evidence.
Every intervention carries a grade, and the grading system is published so any grade can be checked against it: how we grade evidence.
Numbers
Figures are quoted exactly or not at all. Where a number could not be verified against a primary source, the page says so and gives the direction of effect instead of reproducing a figure with no traceable origin. Confidence intervals appear wherever a point estimate is doing persuasive work.
This occasionally means a page declines to answer a question that other sites answer confidently. That is deliberate. During the writing of this site we found at least one widely repeated trial figure that the published analysis does not support, and one drug's boxed warning described incorrectly across multiple sources. Both are corrected here.
Where experts disagree
Major societies do not agree about what counts as low testosterone, whether "functional hypogonadism" is a real category, when free testosterone should be measured, or how older men should be treated. We do not manufacture consensus. The disagreements are mapped atwhy experts don't always agree.
Review and corrections
Guideline-dependent pages are reviewed quarterly. Physiology pages are reviewed annually. A new guideline, an FDA action or a major trial publication triggers immediate review of every page tagged to that topic. Each page carries a visible review date.
Pages currently marked as a working draft are undergoing medical review and primary-source verification. That label is removed page by page as each one clears.
If you think something here is wrong, say so. Corrections are made with a date and a reason rather than quietly. Contact the practice viadiaendo.com.
What this site is not
It is not medical advice, and it is not a substitute for being examined and evaluated by a clinician who knows your history. Nothing here should be used to start, stop or change a prescription on your own.
If you want an evaluation, the practice sees patients in person in San Diego County. If you are outside that area, we have written a page onhow to find a clinician who will evaluate you properly, which sends you elsewhere and is meant to.