hCG: What It Does in Men and Why It Is Not a Peptide

hCG is not a peptide. Human chorionic gonadotropin is a glycoprotein hormone — two subunits with substantial carbohydrate attachment, far larger and more complex than anything in the peptide category. It is grouped with peptides commercially, not chemically.

It is also the most mechanistically distinct compound used on the male hormonal axis.

What it does

hCG shares its alpha subunit with LH, FSH and TSH, and its beta subunit determines what it binds. In practice hCG binds the LH receptor and acts as an LH mimetic.

That means it acts directly on the testes, bypassing both the hypothalamus and the pituitary entirely.

Established clinical uses

hCG is an approved drug with genuine indications, which separates it from most compounds discussed on this site.

• Hypogonadotropic hypogonadism — where the pituitary signal is absent or insufficient.

• Fertility induction in men, often combined with FSH to restore spermatogenesis.

• Ovulation induction in assisted reproduction.

• Cryptorchidism in some paediatric contexts.

• Preserving testicular function alongside testosterone therapy, which is a common off-label use with a clear rationale.

A 2026 review examined the therapeutic benefits of gonadotropins in male hypogonadotropic hypogonadism with a focus on spermatogenesis and fertility, and a 2026 multicentre randomised controlled trial examined gonadotropin therapy in idiopathic hypogonadal non-obstructive azoospermia.

Why it is used with testosterone therapy

Exogenous testosterone suppresses LH and FSH through negative feedback. Without LH, the testes stop producing testosterone locally and stop supporting spermatogenesis — which is why testosterone therapy commonly causes testicular atrophy and impaired fertility.

hCG substitutes for the missing LH signal. It maintains intratesticular testosterone and testicular volume during therapy. The rationale is sound and widely applied, and it does not make the combination self-manageable — it is a prescribing decision requiring monitoring.

The hCG diet

hCG has a long association with a very-low-calorie diet protocol, and this is worth addressing directly.

The weight loss in that protocol comes from the calorie restriction. Controlled trials comparing hCG against placebo alongside the same restricted diet have not found hCG to add benefit. FDA has stated that hCG is not approved for weight loss and has acted against products marketed that way.

Practical considerations

The oestradiol point is the one most often missed. Stimulating the testes raises testosterone and aromatisation together, so oestradiol frequently rises more than expected — which is a reason for bloodwork rather than assumption.

See the peptides for testosterone guide for the full axis, the gonadorelin guide for the pituitary-level alternative, and the reconstitution guide for handling.