HCG (Human Chorionic Gonadotropin)

Half-life

~1 days

Long

minsdays

Route

SubQ injection

Evidence

Approved therapeutic

Risk

Standard

Overview

Known for

Mimics LH (luteinising hormone). Maintains testicular function, fertility, and intratesticular testosterone during TRT. Also used for fertility treatment in both sexes, weight loss protocols, and PCT after steroid cycles.

Mechanism

Mimics LH — signals testes (Leydig cells) to produce testosterone, maintains testicular size/function. In women: triggers ovulation.

Key facts

Format

Lyophilized powder

Mechanism targets

Classification

Authoritative

Supply & nature

ExogenousExogenous

FDA category

Approved (Novarel/Pregnyl)

Evidence & standing

Evidence base

Approved therapeutic

Risk level

Standard

Best studies

5 references

FDA Approved: Multiple brands (Pregnyl, Novarel, Ovidrel) for fertility
Ley & Leonard (1985) JCEM 61:746-52 — Testosterone stimulation
Standard of care for male infertility and ovulation induction
Well-established 60+ years of clinical use
Also used in TRT protocols to maintain fertility/testicular size

Dosage & protocol

Typical dose

250-500 IU

Research range

500–2000 IU

Cycle

Per fertility or HPTA protocol

Onset

10 days first effects

Full effect

56 days

Half-life

~24-36h

~24-36 hours (biphasic: initial 6hr, terminal 24-36hr)

Protocol

Men on TRT: 250-500 IU 2-3x per week SubQ. Fertility: 1000-2000 IU 2-3x per week. Women: per fertility clinic protocol.

Time to effects

EARLY: 1-2 weeks

FULL: 4-12 weeks

Week 1-2: Testosterone increase measurable within days. Some feel improved energy/mood quickly. Testicular 'fullness' if previously atrophied from TRT.

Week 2-4: Clear hormonal improvements. Libido increase. Improved recovery.

Week 4-8: Testicular volume normalised. Hormonal benefits stable.

Week 8-12: Fertility parameters improved (if that was the goal).

Fastest-acting gonadotropin on this list due to direct LH-mimicking action. For fertility: minimum 3-6 months.

Recommended vial

5000 IU vials

At 500 IU 3x/wk, 5000 IU = ~3.3 weeks ✓. 10000 IU = 6.7 weeks — borderline ⚠️. HCG is stable (30-60 days) so 10000 is OK, but 5000 is safer.

Reference figures only

Dosing reflects published laboratory protocols and is not guidance for use in any living subject.

Safety

Reversibility

Fully Reversible

Side effects

Headache, irritability, water retention/bloating, gynecomastia (aromatisation to estrogen), injection site pain, ovarian hyperstimulation (women — OHSS)

Interactions

Aromatase inhibitors (may be needed to control estrogen), testosterone (co-administered commonly), clomiphene

Do not combine

Gonadorelin Acetate

Handle with research caution

Caution combining with Gonadorelin (overlapping LH stimulation)
Monitor estradiol — HCG can increase aromatisation (may need AI)

Storage & handling

Lyophilised

12–24 months

2–8°C

Reconstituted

30–60 days

2–8°C

Videos & talks

Independent educational content from researchers, clinicians and science communicators — not affiliated with Pepnerd.

Educational resources only. Videos are independent third-party content. Pepnerd is not affiliated with these creators and does not endorse or make claims based on their content. All products are for in-vitro research.