Library

hCG

Ancillaries & recovery

Also known as Human chorionic gonadotropin, Pregnyl, Novarel, Ovidrel

Acts like LH at the testis, keeping it working while the body's own signal is suppressed.

How it works

Binds the LH receptor on Leydig cells and drives testosterone production directly, bypassing the pituitary. That is why it maintains testicular volume and function during suppression, and why it does nothing to restore the pituitary signal itself.

SubcutaneousIntramuscular

In the body

Half-life
33 hours
Time to peak
6 h
90% gone after
4.6 d
Builds up to
1.45×
Steady state after about 7 d at twice or three times weekly.
Sep 16Sep 17Sep 18Sep 19Sep 20Sep 21Sep 227:33 PM

Shape of a single dose, modelled as one compartment with first-order absorption. The peak is normalised to 100% because bioavailability and volume of distribution are not published for most of these compounds.

Biphasic: a fast phase of roughly 5 to 9 hours, then a slower terminal phase around 24 to 37 hours. 33 hours is taken from the terminal phase, which is what governs dosing interval. The one-compartment model the app uses cannot show both phases, so the first few hours after a dose are understated.

Your notes

Doses

500 mcg, 1 mgtwice or three times weeklyCommunity practice

500 to 1000 IU per injection, to maintain testicular function during suppression. Community practice; there is no approved dose for this use.

1 mg, 4 mgtwice or three times weeklyClinical trial

1000 to 4000 IU, the range used clinically for hypogonadotropic hypogonadism and fertility restoration.

Vial sizes

5 mg10 mg

Commonly treated as good for 30 days refrigerated once reconstituted.

Side effects

  • Raised oestradiol, since driving testicular output raises the substrate for aromatase
  • Leydig cell desensitisation if held above replacement level for long enough, which is the opposite of the intended effect
  • Injection site reaction
  • Gynecomastia, downstream of the oestradiol rise
  • Monitor: oestradiol and total testosterone

Cautions

  • Known hormone-dependent tumour
  • Sustained high-dose use, which desensitises the receptor it depends on
  • Precocious puberty

Status

Prescription-only. Approved for hypogonadotropic hypogonadism and ovulation induction. Banned in sport at all times for men.

Sources

Reference information for personal record-keeping. Not medical advice, and not a recommendation to use any of these compounds.