A short list of articles, trial summaries, and clinical guidelines we point patients to when they want to understand the evidence behind testosterone therapy — written by people qualified to write them: NEJM, Cleveland Clinic, Mayo, the AUA, peer-reviewed journals.
If you've never been on testosterone therapy and you're trying to figure out whether it might be for you, these four pieces are the most useful first reads.
A measured, plain-language overview from Mayo. Covers how levels change with age, who actually benefits, and the legitimate risks. The most balanced single article we link to.
Harvard Medical School's take. Useful for the skeptic in your life — explains why most "low T" symptoms aren't actually low T, and what to rule out first.
The clinical guideline most US endocrinologists work from. Dense, but the recommendation summary at the top is readable in five minutes.
Government-published primer on what the test measures, when it's ordered, and how to read a result. The most patient-friendly thing on free vs. total testosterone.
The cardiovascular safety question used to be the hard part. TRAVERSE — a 5,246-man randomized trial published in NEJM in 2023 — is the largest answer we have. These pieces unpack it.
The TRAVERSE primary publication. Lincoff, Bhasin et al. 5,246 men with hypogonadism and elevated cardiovascular risk, randomized to testosterone gel vs. placebo for 27 months. Read the abstract and the discussion.
Cleveland Clinic's own writeup of TRAVERSE (they ran the coordinating center). Notable for what the lead investigator says against casual prescribing.
A TRAVERSE substudy on bone fractures. Important counterweight to the assumption that testosterone universally improves bone outcomes — the result is more nuanced than that.
A full review article that walks through TRAVERSE's findings, criticisms, and limits. Atrial fibrillation signal, AKI, the diabetes substudy — all covered.
Standard testosterone therapy suppresses sperm production. If you might want kids — even years from now — the literature on SERMs and fertility-preserving options is essential reading.
Wiehle et al. The pharmacokinetic/pharmacodynamic trial that established enclomiphene as an alternative to TRT for men who want to preserve fertility. LH and FSH stay up; sperm counts don't crash.
A Phase II RCT comparing enclomiphene head-to-head with topical testosterone gel. The clearest demonstration of the fertility tradeoff TRT actually creates — and what avoids it.
A review of the full evidence base. Includes the FDA history (why it isn't approved as a standalone), the fertility data, and an honest discussion of where the evidence is thin.
"Why does my total testosterone look fine but I feel terrible?" Usually the answer is in SHBG and free T. These pieces explain what to actually test for and how the numbers relate.
The American Urological Association's full clinical guideline. The 300 ng/dL diagnostic cut-off, monitoring intervals, when to add free T — all of it sourced here.
The Mayo lab catalog page. Useful for understanding why total and free T aren't interchangeable, and which test your physician should actually order in which scenario.
The study that established why total T between 280–400 ng/dL is genuinely ambiguous, and why a free testosterone measurement matters in that range.
Walks through total T vs. free T vs. bioavailable T, the assay differences, why morning fasting samples matter, and the limits of what a single number can tell you.
Reading the literature is the right first step. The second is sitting with someone who can read your numbers, not the literature's.