A client came to me recently who had been told by her GP, after a ten-minute consultation: "Your symptoms suggest perimenopause. We can offer you HRT." No blood test. No hormone panel. No assessment of oestrogen metabolism, progesterone status, cortisol pattern, or thyroid function. Just symptoms, a clinical impression, and a prescription.
She was 47. Her chief complaints were fatigue, poor sleep, brain fog, weight gain around the midsection, and mood instability. These are the classic symptoms the NHS associates with perimenopause, and the association is often correct. But they are also the classic symptoms of HPA axis dysregulation, subclinical hypothyroidism, oestrogen dominance from impaired metabolism rather than low production, insulin resistance, and gut-driven hormone recirculation. Without testing, you cannot reliably distinguish between them. And the intervention for each is substantially different.
She declined the HRT offer — correctly, as it turned out. Testing revealed depleted cortisol pattern with low DHEA, a 2-OH:16-OH oestrogen ratio of 0.8 (indicating poor protective pathway dominance despite apparently adequate oestrogen levels), elevated beta-glucuronidase on GI-MAP suggesting gut-driven oestrogen recirculation, and TSH of 4.1 with low Free T3. She wasn't short of oestrogen. Her oestrogen wasn't being processed safely, and her gut was recycling what the liver had already packaged for elimination.
Adding more oestrogen into that picture — which is what standard HRT would have done — would not have addressed a single one of the underlying mechanisms. It might have temporarily improved some symptoms. It would have worsened the 2-OH:16-OH ratio and added to an already-burdened elimination pathway.
This is the problem with symptom-only hormone management. Symptoms identify that the hormonal system is dysregulated. They do not identify which hormone is deficient, whether the deficiency is primary or secondary, or whether the hormones present are being processed safely.
"You cannot balance hormones without understanding the nervous system that regulates their production, the liver that metabolises them, and the gut that determines whether they leave the body — or come back."
The first questions before any hormone conversation
Before HRT is appropriate to discuss, the following clinical questions need answers. These are not luxury additions to the consultation. They are the minimum information required to prescribe hormones responsibly.
The oestrogen metabolism pathways — what no standard test shows you
This is the dimension of hormone health that is almost never explained in a standard consultation and that makes an enormous difference to the risk profile of HRT. Oestrogen is metabolised by the liver into three primary pathways. Which pathway dominates is determined by genetics, gut health, methylation status, and lifestyle — and it is the single most important factor in understanding whether a given hormonal picture is a risk or not.
Testing strategies — blood, saliva, and urine compared
The question of which test to use for hormones has a historical context that is worth understanding. Each medium has been championed by different schools of thought, each has genuine strengths, and none is complete on its own.
| Method |
What it measures |
Strengths |
Limitations |
Best used for |
| Blood serum |
Total circulating hormones (bound + unbound). FSH, LH, oestradiol, progesterone, testosterone, DHEA-S, SHBG, TSH, Free T3/T4. |
Large evidence base. NHS standard. Useful for FSH/LH (ovarian failure confirmation). Total testosterone and SHBG allow free testosterone calculation. Good for thyroid panel. |
Single time point — misses diurnal variation. No metabolite information. Cannot assess 2-OH/4-OH/16-OH pathways. Oestradiol appears normal with dangerous metabolism. Misses progesterone metabolites. Poor cortisol rhythm data. |
Initial screening, FSH confirmation of menopause, thyroid function, SHBG for free hormone calculation, DHEA-S. |
| Saliva |
Free (unbound) hormone fraction. Particularly cortisol, oestradiol, progesterone, testosterone, DHEA. |
Non-invasive. Captures free fraction only — arguably more biologically relevant. Diurnal cortisol can be measured at multiple points. Used extensively in early functional medicine research. |
Lower volume of peer-reviewed validation than blood or urine. Contamination sensitivity (food, blood from gum disease). Limited metabolite information. Less standardised reference ranges. Largely superseded by dried urine for most purposes. |
Diurnal cortisol sampling where DUTCH is unavailable. Limited contemporary clinical use for sex hormones. |
| Dried urine (DUTCH) |
Hormone metabolites across 24 hours. Cortisol diurnal pattern + CAR. Oestrogen pathway metabolites (2-OH, 4-OH, 16-OH, methylation markers). Androgen metabolites. Progesterone metabolites. Melatonin. Neurotransmitter metabolites. |
Most comprehensive single hormone assessment available. Captures metabolic processing — not just levels. Full cortisol picture (pattern, not just point). Oestrogen pathway safety assessment. Collected at home, multiple time points. Methylation markers (4-MeO:4-OH ratio). Growing peer-reviewed validation base. |
Not available on NHS. Cost barrier. Requires interpretation training. Cannot replace FSH/LH for menopause confirmation. Expensive relative to serum panel. |
Comprehensive functional hormone assessment. Essential for any woman considering HRT. Essential for unexplained hormonal symptoms. Monitoring HRT efficacy and safety. MTHFR-related hormone risk assessment. |
Delivery methods — the clinical case for each and its limitations
How a hormone is delivered determines its absorption profile, its first-pass metabolism through the liver, its effect on SHBG, its monitoring requirements, and its risk profile. This is not a minor practical detail — it is a fundamental clinical variable that substantially changes the benefit-risk calculation.
| Method |
First-pass liver |
Advantages |
Limitations / Risks |
Monitoring |
| Oral / Capsule |
Yes — significant |
Convenient. Well-studied (though mostly synthetic forms). Micronised progesterone (Utrogestan) orally is the exception — evidence-based and preferred over synthetic progestogens for uterine protection. |
Significant liver first-pass metabolism. Raises SHBG (reducing free hormone availability). Oral synthetic oestrogen increases clotting factors and cardiovascular risk — this is largely what the WHI study found. Oral bioidentical oestradiol is better but still carries more hepatic load than transdermal. |
Serum levels 4 hours post-dose. Liver function. Clotting factors if standard oral oestrogen. |
| Transdermal patch |
Bypassed |
Gold standard for oestradiol delivery in NHS and most evidence-based guidelines. Bypasses liver first-pass — no increase in clotting factors or SHBG. Most studied transdermal delivery. Consistent absorption. Once or twice weekly application. |
Skin reactions at application site in some women. Absorption varies with skin integrity and site rotation. Not ideal for monitoring DUTCH metabolites (patch oestradiol shows differently in urine). |
Serum oestradiol. Symptom response. DUTCH can be used but requires timing awareness relative to patch application. |
| Transdermal gel / cream |
Bypassed |
Flexible dosing. Good for dose titration. Bioidentical oestradiol gel (Oestrogel, Sandrena) is widely available on NHS. Testosterone cream/gel increasingly available. |
Absorption variability — skin thickness, site, application technique. Transfer risk to partner or children if applied to arms or neck. Progesterone cream is poorly absorbed transdermally and should not be relied upon for uterine protection. |
Serum oestradiol, testosterone. Symptom response. DUTCH if monitoring metabolites. |
| Sublingual drops / troches |
Partially bypassed |
Rapid absorption. Good for bioidentical compounded formulations. Allows individualised dosing. Useful where skin absorption is poor. Some practitioners prefer for progesterone and testosterone. |
Less evidence base than patch or gel. Compounding regulation variable. Absorption inconsistent if not held correctly. Not available on NHS — requires private compounding pharmacy. DUTCH monitoring important given variable absorption. |
DUTCH plus serum for cross-reference. Symptom tracking essential. |
| Liposomal (oral) |
Largely bypassed via lymphatic absorption |
Phospholipid delivery improves absorption of progesterone and DHEA significantly. Quicksilver Scientific and similar produce clinically validated formulations. Useful where conventional routes are declined or problematic. Good evidence for progesterone and DHEA specifically. |
Less peer-reviewed evidence than licensed products. Not NHS-available. Cost. Quality depends significantly on manufacturer — not all "liposomal" products are equivalent. Requires practitioner supervision for sex hormone use. |
DUTCH for metabolite monitoring. Serum for cross-reference. Clinical symptom tracking. |
| Pellet implants |
Bypassed |
Sustained release over 3–6 months. No daily compliance requirement. Consistent levels without peaks and troughs. Widely used in US private practice for testosterone in both sexes. |
Cannot be removed if side effects occur — committed to dose until pellet dissolves. Dose adjustment impossible mid-cycle. Not widely available in UK. Risk of supraphysiological levels, particularly testosterone. Polycythaemia risk. |
Serum hormone levels at 4–6 weeks post-insertion. Regular monitoring throughout cycle. |
| Intramuscular injection |
Bypassed |
High bioavailability. Widely used for testosterone replacement in men. Well-studied for TRT. |
Peaks and troughs — energy and mood fluctuate with injection timing. Requires clinical administration or patient training. Less common for women's HRT in UK practice. |
Serum testosterone mid-cycle between injections. Haematocrit (polycythaemia risk). PSA in men. |
The synthetic versus bioidentical distinction — and why it matters
The Women's Health Initiative (WHI) study of 2002 — the landmark trial that caused widespread abandonment of HRT — used conjugated equine oestrogen (Premarin, derived from pregnant mares' urine) and medroxyprogesterone acetate (a synthetic progestogen). The findings — increased breast cancer and cardiovascular risk — were real and important. But they applied to those specific compounds given orally to women who were, on average, 63 years old and more than ten years post-menopause.
The application of those findings to bioidentical oestradiol delivered transdermally to women in perimenopause or early menopause was, to put it directly, a scientific error with significant clinical consequences. The two are not the same compound delivered by the same route at the same dose to the same population. They are meaningfully different in almost every variable that determines risk.
Bioidentical hormones are structurally identical to the hormones produced by the human body. They bind the same receptors in the same way. They are metabolised via the same pathways. The oestrogen metabolite picture from bioidentical oestradiol is functionally the same as the endogenous oestradiol picture — and therefore monitorable via DUTCH in the same way. Synthetic progestogens do not bind progesterone receptors identically and produce different downstream effects — including androgenic effects, mood effects, and differential breast tissue effects — from micronised progesterone.
The current UK consensus (NICE guideline NG23, updated 2019, and the British Menopause Society guidance) has substantially revised the risk framing. Transdermal oestradiol with micronised progesterone (Utrogestan) is now regarded as the safest HRT formulation for most women, with a risk profile substantially better than the WHI data suggested for the older oral synthetic formulations.
The Timing Hypothesis — When HRT Helps and When It May Not
There is now substantial evidence for what is called the "window of opportunity" or timing hypothesis: HRT initiated within ten years of menopause, or before age 60, appears to be cardioprotective — improving lipid profiles, endothelial function, and reducing cardiovascular risk. HRT initiated more than ten years after menopause, or after age 70, in women with established atherosclerosis may carry different risk. This is a nuanced finding that cannot be reduced to "HRT is safe" or "HRT is dangerous" — it is population, timing, formulation, and individual biology. Which is precisely why individual assessment, including testing, matters more than population-level guidance applied without clinical judgment.
Progesterone — the most undervalued hormone in the conversation
Most of the public conversation about HRT focuses on oestrogen. Progesterone is the hormone that is quietly doing much of the most important work — and its absence or inadequacy explains a significant proportion of the symptom burden that is attributed to oestrogen deficiency.
Progesterone is a GABA receptor agonist through its metabolite allopregnanolone. This is the mechanism by which progesterone reduces anxiety, supports sleep, and produces the calming effect that many women notice in the luteal phase when progesterone is at its monthly peak. When progesterone drops — through HPA-axis-driven pregnenolone steal, through perimenopause, or through anovulatory cycles — GABA tone drops simultaneously. The anxiety, insomnia, and mood instability that follow are frequently attributed to "hormones" without the specific mechanism being identified.
The progesterone metabolite (pregnanediol) on DUTCH shows both the level and the timing of progesterone production. A woman with adequate serum progesterone on a midluteal blood test may still show poor DUTCH pregnanediol — indicating that the progesterone is not being adequately metabolised to the active allopregnanolone form. This distinction is invisible on blood testing and clinically significant.
What genuine monitoring looks like
HRT without monitoring is prescribing in the dark. The minimum clinical standard for anyone on HRT — NHS or private, synthetic or bioidentical — should include:
- Baseline DUTCH Plus before initiating, to establish oestrogen metabolism pathway status, cortisol pattern, progesterone metabolites, and methylation markers. This becomes the reference point against which treatment is evaluated.
- Repeat DUTCH at 3 months after initiating HRT — particularly to assess whether the 2-OH:16-OH ratio has improved or worsened, and whether the 4-OH methylation pathway is clearing adequately.
- Serum oestradiol and testosterone to confirm circulating levels are in the physiological range — not supraphysiological, which is a risk with some compounded formulations.
- GI-MAP with beta-glucuronidase if oestrogen dominance symptoms persist despite apparently adequate HRT — gut-driven oestrogen recirculation will undermine any hormonal intervention.
- MTHFR status and homocysteine — impaired methylation affects oestrogen clearance via the 4-OH pathway. Women with confirmed MTHFR variants who are considering HRT should have methylation support established before or alongside hormonal therapy.
The case for doing nothing — and the case against it
HRT is not appropriate for everyone. There are women for whom the upstream drivers — HPA axis, thyroid, gut, methylation — account for most of the symptom burden, and for whom addressing those drivers without adding exogenous hormones produces excellent outcomes. Margaret, the case study from my clinical records described in an earlier context, is exactly this: offered HRT, declined it, had the upstream drivers identified and addressed, and recovered fully without exogenous hormones at all.
There are also women for whom genuine, primary gonadal hormone insufficiency — confirmed by FSH, oestradiol, and progesterone testing — is causing real and significant harm: bone loss, cardiovascular risk, vaginal atrophy, severe vasomotor symptoms, cognitive decline. For these women, withholding HRT on the grounds of vague, population-level risk framing is its own form of clinical negligence. The evidence for HRT in this context, initiated appropriately and monitored properly, is good.
The honest position is: test before deciding. Know what the oestrogen metabolism picture looks like before adding oestrogen. Know whether the gut is recycling what the liver is trying to excrete. Know whether the symptoms are primary gonadal insufficiency or secondary HPA dysregulation. And if HRT is indicated — use the safest available delivery method, monitor the metabolite picture, and support the methylation pathway that determines whether the therapy is being processed safely.
"The question is never simply whether to use HRT. It is: which hormone, in which form, at which dose, via which route, at which stage, for which woman — with what monitoring in place. That is a clinical investigation, not a ten-minute consultation."