TL;DR
- Good trans endocrinology care relies on a set of well-established principles: appropriate monitoring, evidence-based targets, individualised adjustment, and familiarity with the literature
- The Endocrine Society recommends hormone testing every three months during the first year, then every six to twelve months once stable — this is a guideline recommendation, not a universal law
- Results should be interpreted using appropriate reference intervals and guideline targets rather than default laboratory flags alone
- Most guidelines aim for testosterone suppression below 50 ng/dL and estradiol concentrations within the physiological premenopausal female range, with dose adjusted accordingly
- If your care doesn’t include these basics, you now know what to ask for
Many trans women do not receive care that fully reflects current guideline recommendations. This is not because good care is complicated. It is because the system does not require it, and many clinicians treating trans patients were never specifically trained to provide it.
Although practice varies, there are several well-established principles that characterise good endocrine care. Here is what they look like.
Monitoring frequency
Endocrine Society guidelines specify hormone testing every three months during the first year of HRT, then every six to twelve months once stable. This frequency exists because estradiol and testosterone levels can vary significantly in early treatment as doses are adjusted, and because the first year is when most dose titration occurs. It is worth knowing that this recommendation is graded as conditional rather than strong, reflecting the limited direct trial evidence in trans health discussed elsewhere on this site — which means there can be legitimate clinical reasons for a different schedule, but it should be a decision your clinician makes and explains, not a default.
In some settings, hormone monitoring may occur less frequently than guideline recommendations suggest. Without measurement, clinicians have limited ability to determine whether a prescribed regimen is achieving its intended hormonal targets — and standard doses do not always achieve therapeutic targets, as individual variability in absorption and metabolism can be substantial.
What gets measured
The standard monitoring panel includes estradiol and total testosterone. Where testosterone suppression is inadequate despite apparently therapeutic estradiol levels, calculating bioavailable testosterone using SHBG and albumin may add useful information. Persistent nonsuppressed testosterone despite apparently adequate estradiol levels is a recognised clinical problem and does not necessarily indicate non-adherence. Additional markers that may be relevant include prolactin (particularly with cyproterone acetate), blood pressure, lipid profile, and, in selected circumstances, liver function tests — because HRT can have systemic effects beyond the sex hormones themselves.
How results are interpreted
One area in which misunderstandings can arise is interpretation of laboratory results. Total testosterone reported against a male reference range is clinically misleading. A result described as “low” on a male range chart may still be above the therapeutic target of below 50 ng/dL. Estradiol reported without reference to the physiological female range and guideline target is similarly incomplete.
Testosterone results are generally interpreted against treatment targets rather than male laboratory reference ranges, and estradiol concentrations are usually assessed in the context of physiological female ranges and the overall clinical picture. Prolactin should be interpreted against a female reference interval. For those on injectable estradiol, serum concentrations vary substantially over the dosing interval, meaning that blood drawn immediately before the next injection (a trough level) may look very different from blood drawn earlier in the cycle, and a result interpreted without knowing when in the cycle it was drawn can be misleading. If your clinician has told you your testosterone is “fine” without specifying against which range, that is worth clarifying directly.
Dose adjustment
Good care does not initiate HRT and walk away. It initiates, measures, reviews, and adjusts. If estradiol is subtherapeutic, the regimen may require adjustment, including dose modification or reconsideration of route — though adherence, timing of the blood draw, and assay variability are also worth ruling out first. If testosterone is not suppressing to target, the regimen needs review — antiandrogen choice, dose, or route of estradiol. If adverse effects emerge, the risk-benefit balance needs reassessment.
This is individualised medicine. It requires a clinician who engages with the results rather than simply noting them.
What to ask for
If you are currently receiving HRT and are not sure whether your care meets these standards, these are reasonable questions to raise with your prescriber:
- How often are my hormone levels being checked?
- What are my current estradiol and testosterone levels, and what targets are we aiming for?
- Is my testosterone being interpreted using treatment targets rather than the default male laboratory reference range?
- Has my prolactin been checked if I am taking cyproterone acetate?
- When was my dose last reviewed against my measured levels?
You should be able to get clear answers to all of these. Difficulty obtaining clear answers may indicate an opportunity for further discussion or review of the treatment plan.
⚠️ Note: Monitoring standards cited are from Endocrine Society Clinical Practice Guidelines. Individual clinical circumstances may mean your care differs from these standards for valid reasons — the key is that departures are clinician-led and explained, not the result of system gaps or limited trans-specific knowledge.
Sources
- Hembree WC, Cohen-Kettenis PT, Gooren L, et al. Endocrine Treatment of Gender-Dysphoric/Gender-Incongruent Persons: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2017;102(11):3869–3903.
- ARUP Consult. Endocrine Testing in Transgender Adults.
- Cheung AS, et al. Approach to prolactin monitoring and hyperprolactinaemia in transgender and gender-diverse individuals undergoing gender affirming hormone therapy.
- Approach to Nonsuppressed Testosterone in Transgender Women Receiving Gender-Affirming Feminizing Hormonal Therapy. Journal of the Endocrine Society.
