hCG

What it is

Human chorionic gonadotrophin is a hormone produced in pregnancy that acts on the same receptor as luteinising hormone. In men that means it stimulates the testes directly, bypassing the suppressed signalling from the brain. It has clear licensed uses in fertility medicine.

It is prescribed to trigger ovulation in fertility treatment, and in men to stimulate testosterone and sperm production in specific diagnosed conditions, under specialist supervision.

What’s claimed

• Preventing or reversing testicular atrophy during steroid use
• Maintaining fertility
• Rapid weight loss on the 'hCG diet'

What the evidence shows

That hCG stimulates testicular function is well-supported (Gold): it is why the drug exists, and the fertility-preservation rationale has a real mechanism behind it, though self-directed use has not been shown to reliably deliver it. The hCG diet is a separate matter and is straightforwardly not supported: controlled trials found hCG produced no weight loss beyond the severely restricted diet it accompanied, and regulators in several countries have acted against products marketing it.

The risks

• Endocrine: it can raise oestrogen substantially through increased aromatisation, and prolonged use desensitises the very cells it stimulates.
• Thrombotic and ovarian effects in women, including ovarian hyperstimulation syndrome.
• Product risk: it is a peptide hormone requiring careful handling, and the unregulated market supplies both counterfeits and mislabelled products.
• The hCG diet specifically: the severe energy restriction it is paired with is the actual and dangerous mechanism, not the hormone.

What needs monitoring

• Testosterone and oestradiol
• Semen analysis where fertility is the concern
• This is a prescription hormone; a doctor is the right person to be involved.