Overview
HCG is classified as a PCT (post-cycle therapy) and ancillary compound. Glycoprotein hormone — LH analog.
With a half-life of ~1.2 days (29 hours), HCG supports less frequent dosing schedules. Administered via SubQ and IM injection, it has a bioavailability of approximately 45% via its primary route.
Half-life approximately 29 hours. Subcutaneous bioavailability approximately 45%. Requires reconstitution and refrigerated storage. One-compartment model.
Mechanism of Action
HCG's pharmacological activity involves the following key pathways:
Gonadotropin Activity
HCG provides exogenous gonadotropin stimulation, directly activating receptors in gonadal tissue.
LH/FSH Mimicry
HCG mimics the activity of endogenous gonadotropins, stimulating target tissue function.
Dosing Protocols
The following protocols represent commonly observed dosing patterns. These are observational summaries, not recommendations.
Dose
250 IU
Route
Subcutaneous
Frequency
Every other day
Duration
4-8 weeks
Dose
1500 IU
Route
Subcutaneous
Frequency
Every other day
Duration
4-8 weeks
Reconstitution Steps
HCG is supplied as a lyophilized (freeze-dried) powder and requires reconstitution before use. Common vial sizes: 2,000 IU, 5,000 IU, 10,000 IU.
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1
Gather supplies
You will need your HCG vial (lyophilized powder), a vial of bacteriostatic water (BAC water), two insulin syringes or a 3 mL syringe with a mixing needle, alcohol swabs, and a sharps container.
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2
Clean and prep
Wipe the rubber stoppers of both the HCG vial and BAC water vial with separate alcohol swabs. Allow them to air-dry for 10–15 seconds before proceeding.
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3
Draw BAC water
Draw 1–2 mL of bacteriostatic water into your syringe. The exact volume depends on your desired concentration — 1 mL per 5000 IU vial gives a straightforward concentration for dosing calculations.
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4
Add water to HCG
Insert the needle into the HCG vial and slowly inject the BAC water down the side of the vial. Do not spray it directly onto the powder pellet or shake the vial — swirl gently until the powder fully dissolves. The solution should be clear and colourless.
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5
Label and store
Label the vial with the date of reconstitution and concentration (e.g., 5000 IU / 1 mL). Store immediately in the refrigerator at 2–8°C. Use within 60 days.
Quick Reconstitution Math
5,000 IU vial + 1 mL BAC water = 5,000 IU/mL. A 250 IU dose = 0.05 mL (5 units on a 100-unit insulin syringe). A 500 IU dose = 0.1 mL (10 units). Use the Milligram reconstitution calculator for custom vial sizes.
Reconstituted HCG is stable for up to 60 days refrigerated at 2–8°C. Lyophilized powder can be stored at room temperature but refrigeration extends shelf life. Never freeze reconstituted solution.
Frequently Asked Questions
What is HCG and how does it work for PCT?
Human Chorionic Gonadotropin (HCG) is a glycoprotein hormone that mimics luteinizing hormone (LH) in the body. During or after anabolic steroid use, the testes can become desensitized to LH signaling due to suppressed endogenous production – HCG directly stimulates the Leydig cells in the testes to resume testosterone production. It is commonly used either during a cycle to prevent testicular atrophy or in the early phase of post-cycle therapy to prime the testes before introducing SERMs.
What is the typical HCG dosing protocol for PCT?
Community protocols commonly reference 250–500 IU administered 2–3 times per week, with some practitioners using a short high-dose blast of 1000–2000 IU daily for 5–10 days at the start of PCT. The half-life of HCG is approximately 33 hours, which supports an every-other-day or twice-weekly injection schedule. Dosing strategy often depends on the duration and suppression level of the preceding cycle.
Should HCG be used during a cycle or only for PCT?
HCG is frequently used in both contexts depending on the protocol. During a long cycle, 250 IU twice weekly is a common approach to maintain testicular volume and sensitivity, making the post-cycle recovery phase faster and more complete. When used solely during PCT, a short front-loaded phase before starting SERMs like Clomid or Nolvadex is a widely observed approach – the goal is to restore Leydig cell responsiveness before the SERM takes over to stimulate the pituitary.
Does HCG increase estrogen levels?
Yes, HCG stimulates testosterone production in the testes, and testosterone aromatizes to estradiol. Elevated HCG doses can lead to noticeable increases in estrogen, which is one reason many practitioners pair HCG with an aromatase inhibitor (AI) during use. This estrogen elevation is an important variable to consider when monitoring bloodwork during and after a cycle.
How long does HCG take to work?
HCG has a half-life of approximately 33 hours, and measurable effects on testicular testosterone output are typically observed within 48–72 hours of the first injection. Testicular volume changes and improvements in sperm parameters are generally reported within 2–4 weeks of consistent use. Full recovery of the hypothalamic-pituitary-testicular (HPT) axis depends on multiple factors beyond HCG alone, including total suppression duration.
Does HCG require refrigeration after reconstitution?
Yes – once reconstituted with bacteriostatic water, HCG should be stored in the refrigerator at 2–8°C and is generally considered stable for up to 60 days when handled correctly. The lyophilized (dry) powder form is more stable and can be stored at room temperature or refrigerated prior to mixing. Light and heat degrade the hormone, so keeping reconstituted vials in the back of the refrigerator away from the door is standard practice.