AI, HCG, and adjunct therapies on TRT

Standard TRT is testosterone replacement on its own. For a significant minority of men, adjuncts improve outcomes or solve specific problems. The commonly used ones in UK private practice are aromatase inhibitors (anastrozole), human chorionic gonadotrophin (HCG), and clomiphene. This article explains what each one does, when it helps, and when it is unnecessary or counterproductive.

Anastrozole (an aromatase inhibitor)

Anastrozole blocks the conversion of testosterone into oestradiol. It is used in breast cancer treatment at higher doses; in men's hormone management it is used at low dose (typically 0.25 to 0.5mg once or twice a week) to manage elevated E2 on TRT.

When it helps: men with symptomatic gynaecomastia on TRT, disproportionate water retention, or E2 rising well above physiological range (typically over 200 to 250 pmol/L) despite reasonable testosterone doses. Higher-body-fat men aromatise more and are more likely to need it.

When it is not needed: most men on TRT. Modest E2 elevation is physiologically appropriate and crushing it below the male reference range causes problems - joint pain, mood instability, reduced libido, lipid deterioration, impaired bone health. The commercial and forum culture of "aggressive E2 management" is clinically wrong for most men.

Our approach: we use anastrozole only where there is a clear indication. Dose is always low and monitored. We re-check E2 at four to six weeks after starting and adjust. We stop if there is no clear ongoing benefit.

Cost: anastrozole is inexpensive generically. It is included in our ongoing care plans where clinically needed at no extra charge.

HCG (human chorionic gonadotrophin)

HCG is an LH analogue that stimulates the testicular Leydig cells directly. It mimics the natural signal that standard TRT suppresses.

When it helps:

Fertility preservation during TRT. Low-dose HCG (500 IU subcutaneous twice weekly) alongside testosterone can maintain intratesticular testosterone and spermatogenesis. Useful for men who want to preserve fertility without sperm banking. Effectiveness varies; some men maintain full spermatogenesis and others do not, so semen analysis at 3 and 6 months confirms.

Preventing testicular atrophy. TRT causes testicular shrinkage (sometimes modest, sometimes substantial) that some men dislike. Low-dose HCG preserves testicular size during TRT.

Restoring spermatogenesis when stopping TRT. Higher-dose HCG (1500 to 3000 IU twice weekly), sometimes combined with FSH or clomiphene, restarts the suppressed pituitary-testicular axis. Used when men on TRT decide to restart fertility or come off testosterone entirely.

As primary treatment in some men with secondary hypogonadism who want to avoid TRT itself. HCG monotherapy can raise testosterone by stimulating the testes. Less predictable than TRT; useful in specific contexts.

When it is not needed: men who have completed their family, have no cosmetic concern about testicular size, and want simplicity. Standard TRT alone is appropriate for this group.

Cost: HCG injection vials add £40 to £80 per month to the regimen depending on supplier and dose.

Clomiphene citrate

Clomiphene is a selective oestrogen receptor modulator (SERM) that blocks oestrogen feedback at the hypothalamus, causing increased GnRH, LH, and FSH, and consequently raising endogenous testosterone production.

When it helps:

Alternative to TRT in secondary hypogonadism. In men with clearly secondary hypogonadism (low T with low-normal LH/FSH) who want to avoid injectable or transdermal treatment or who want to preserve fertility, clomiphene at 25mg daily or alternate days can raise testosterone into normal range in a meaningful proportion. Response is variable; bloods after 6 to 12 weeks confirm.

Restoring fertility in men coming off TRT. Often combined with HCG for post-TRT recovery.

Men with low T who want children now. Rather than TRT, clomiphene raises testosterone without shutting down sperm production.

When it is not needed: primary hypogonadism (the testes themselves are failing; no amount of pituitary stimulation helps), men who respond well to standard TRT with no fertility concerns, or men who have tried clomiphene with inadequate testosterone rise.

Side effects: visual disturbances (rare but important - stop immediately if they occur), mood changes, headache, hot flushes. Well tolerated in most men but not universally.

Cost: clomiphene is inexpensive but is an off-label use in men (the NHS prescribes it for female fertility). We prescribe privately when appropriate.

FSH (follicle stimulating hormone)

Used almost exclusively for fertility restoration in men with poor response to HCG alone. Adds direct FSH stimulation of testicular sperm production. Expensive and specialist-level use.

What we do not routinely prescribe

Selective androgen receptor modulators (SARMs). Not licensed, quality control is poor in the grey market, long-term safety unknown. We do not prescribe these.

Growth hormone and IGF-1 in the absence of deficiency. Growth hormone replacement has a place in confirmed GH deficiency (post-pituitary surgery, head injury, specific genetic causes). "Anti-ageing" GH use in men with normal IGF-1 is outside evidence-based practice and we do not prescribe.

High-dose aromatase inhibitors. Crushing E2 is harmful. We do not do this under any framing.

Proviron (mesterolone). An oral androgen used occasionally in continental European practice. Evidence base is thin; we do not prescribe routinely.

When we add adjuncts

In practice, about 60 percent of our TRT patients are on straight testosterone monotherapy. Roughly 25 percent add low-dose anastrozole for E2 management. Around 10 to 15 percent use HCG for testicular preservation or fertility preservation. A smaller number use clomiphene either as primary treatment or during post-TRT recovery.

The default is simplicity. Adjuncts added because there is a specific reason, not by default.

Monitoring when on adjuncts

Adding anastrozole requires E2 rechecks at 4 to 6 weeks then every 3 months. Adding HCG to preserve fertility requires semen analysis at 3 and 6 months plus ongoing testosterone monitoring. Clomiphene monotherapy requires full hormone panel at 6 to 12 weeks after starting.

The honest bottom line

Adjuncts have real clinical value in specific cases. They are not good additions by default, and the forum culture of aggressive stacks is clinically inappropriate for almost all men. Our job is to add adjuncts when they are needed and to keep the regimen as simple as possible otherwise.

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