What Is HCG? Complete Guide to Human Chorionic Gonadotropin for Steroid Cycles & TRT (2026)

Human chorionic gonadotropin (HCG) is one of the most clinically important ancillary compounds in anabolic steroid use — and one of the most misused. It is not an anabolic steroid, and it does not build muscle. What it does is critically valuable: it mimics luteinising hormone (LH) at the testicular level, maintaining testicular function, testosterone production capacity, and fertility during cycles that would otherwise completely suppress these functions. This guide covers its complete mechanism, dosing protocols, and the key strategic decisions around when and how to use it.

What Is HCG?

Human chorionic gonadotropin is a glycoprotein hormone naturally produced by the syncytiotrophoblast cells of the placenta during pregnancy. Its physiological role in pregnancy is to maintain the corpus luteum's progesterone production during early gestation — the biological basis of pregnancy testing, since HCG is detected in urine. In clinical pharmacology, pharmaceutical HCG is produced from the urine of pregnant women or via recombinant DNA technology and is used for:

• Hypogonadotropic hypogonadism (stimulating testicular testosterone production where LH is deficient)
• Male infertility (improving sperm production)
• Cryptorchidism (undescended testicle) in boys
• Ovulation induction in women undergoing fertility treatment

How HCG Works in the Context of Steroid Cycles

When anabolic steroids suppress the HPG axis, LH and FSH production falls to near-zero. Without LH signalling:

• Leydig cells in the testes stop producing testosterone
• Testicular volume decreases (testicular atrophy)
• Spermatogenesis is impaired
• The testes become desensitised to LH signalling over time

HCG is structurally similar to LH and binds the LH/CG receptor on testicular Leydig cells. Exogenous HCG therefore directly stimulates:

• Testicular testosterone production (maintained throughout the cycle)
• Testicular volume maintenance (preventing atrophy)
• Preservation of the intratesticular testosterone environment necessary for spermatogenesis
• Preventing Leydig cell desensitisation that makes HPG recovery harder post-cycle

HCG During Cycle vs HCG in PCT: The Strategic Choice

There are two schools of thought on HCG timing — both with merit:

Option 1: HCG Throughout the Cycle (Recommended)

Using HCG at a low, consistent dose throughout the anabolic steroid cycle maintains testicular function continuously:

• Protocol: HCG 250–500 IU twice weekly (Monday/Thursday) throughout the cycle
• Effect: Prevents atrophy; maintains intratesticular testosterone; prevents Leydig desensitisation; makes PCT more effective because the HPG axis starting point is more responsive
• Preferred for: Longer cycles (12+ weeks); users concerned about fertility; users who want faster PCT recovery

Option 2: HCG Pre-PCT Blast (2–3 Weeks Before PCT)

A short, higher-dose HCG course run in the gap between the last steroid injection and PCT initiation:

• Protocol: HCG 500–1000 IU every other day for 2–3 weeks, then begin PCT
• Effect: Restimulates Leydig cells that have been desensitised; “wakes up” testicular function before SERMs begin HPG recovery
• Limitation: Does not prevent atrophy during the cycle; Leydig cells may need significant restimulation after a long cycle

See our complete PCT guide for how HCG integrates into full PCT protocols, and our HCG and PCT guide for full details.

HCG in TRT

Men on testosterone replacement therapy who wish to preserve fertility or testicular volume use HCG as an adjunct. Standard TRT-add protocol: HCG 500 IU twice weekly alongside the testosterone dose. This maintains intratesticular testosterone levels necessary for spermatogenesis that exogenous testosterone alone does not provide. See our TRT complete guide. Browse available HCG products.

HCG Dosage Reference Table

Application	Dose	Frequency	Duration
On-cycle maintenance	250–500 IU	Twice weekly	Throughout cycle
Pre-PCT blast	500–1000 IU	Every other day	2–3 weeks
TRT adjunct (fertility)	500 IU	Twice weekly	Ongoing with TRT
Hypogonadotropic hypogonadism (medical)	1000–4000 IU	3x/week	Varies; medical supervision required

Side Effects of HCG

• Oestrogen elevation: Testicular stimulation by HCG produces testosterone which aromatises to oestradiol. At doses above 500 IU per injection, oestrogen can rise significantly. An AI may be required during high-dose HCG protocols.
• Desensitisation at high doses: Paradoxically, chronic high doses of HCG (>500 IU every other day long-term) can downregulate LH/CG receptors on Leydig cells, reducing sensitivity. This is why low, consistent doses are preferred over high infrequent doses for on-cycle use.
• Gynaecomastia: Via oestrogen elevation; AI management required at higher doses
• Water retention: From elevated oestradiol
• Mood effects: Variable; usually positive (improved testosterone, libido) but oestrogen elevation can cause mood instability at high doses

Reconstitution and Storage

HCG is supplied as lyophilised powder with a separate diluent vial. Reconstitute with the provided diluent or bacteriostatic water. Reconstituted HCG should be refrigerated and used within 28–30 days. Inject subcutaneously or intramuscularly with a 25–27 gauge needle.

Frequently Asked Questions

Does HCG prevent testicular atrophy completely?

At doses of 250–500 IU twice weekly during a cycle, HCG significantly reduces but does not always completely prevent testicular volume reduction. Complete prevention may require higher doses, which introduce greater oestrogen-related side effects. The majority of users on 500 IU twice weekly report minimal to no noticeable atrophy.

Can you use HCG alone as a testosterone replacement?

In men with secondary hypogonadism (where the testes are functional but LH signalling is absent), HCG can stimulate testosterone production effectively. Some men prefer this approach for fertility preservation. It is not appropriate for primary hypogonadism (testicular failure) where the testes cannot respond to LH/HCG stimulation.

Is HCG a banned substance in sport?

Yes. WADA prohibits HCG in male athletes at all times, as it is a peptide hormone with the potential to stimulate endogenous testosterone production. It is not prohibited in female athletes in the same context. Athletes subject to anti-doping testing must be aware of this prohibition.