T Nation

hCG Scientific Dosing


Hello all!

Been a while since I posted here. I have been lurking however, I see that most of the old timer vets have disappeared. This post is sort of a refresher on the current usage of hCG on cycle. Has anything changed in regards to the hCG usage protocol? Is it still the standard 500iu/wk that still stands (split into bi-weekly shots)? I read on another site of an alternative method that is apparently backed by science. This is what the post said:

"From my latest research (taken from a recent article by the Endocrinology Society) i am now using and advocating the protocol of 1000iu injected once weekly.

Here is the science behind this protocol:

An in vivo injection or an episode of LH secretion induced by GnRH, results in stimulation of the side-chain cleavage enzyme with the subsequent release of testosterone within 30-60 minutes of LH stimulation. The acute response to an injection of LH is dramatic in some species such as the rat and the ram but is much more attenuated in the human. This testosterone response lasts approximately 24-48 hours. If human chorionic gonadotrophin is used as an LH substitute, the kinetics of the initial stimulation are similar to LH but a second peak of testosterone secretion is evidence with hCG and occurs 48-72 hours after the initial injection. This biphasic pattern has been attributed to the observation that between 24 and 48 hours after an LH or hCG injection, the Leydig cells are refractory to further stimulation by either hormone. The second phase of testosterone secretion after hCG but not LH is associated with the longer half-life of hCG in comparison to LH. The hCG levels persist in the circulation and, following recovery from the refractoriness, testosterone levels increase. This observation has significant clinical importance since, in many men, a single weekly injection of hCG will suffice to maintain optimum testosterone responses rather than the frequent practice of giving injections of hCG two to three times per week.

The stimulation of leydig cells with large amounts of hCG rapidly reduces their number of receptors, this phenemenom is termed down-regulation.

Although these changes decrease testosterone levels to just above diurnal maxima 24-48hrs after initial injection repeated stimulation does not yield the same results.

A single injection of hCG is followed by a long steroidogenic response characterized by two phases of testosterone secretion.

Studies show that this second phase which can last as long as 8 days can increase testosterone in plasma by 2.2 x above maximal diurnal secretion even though hCG is no longer present in plasma.

The results indicate that hCG injections can be given every 6-7 days due to the prolonged steroidogenic response.

It is advisable to start this protocol around week 2-3 in the cycle and continue till the start of PCT."

Not sure if anyone with scientific knowledge still posts here but what do you think about the above information? A single 1000iu shot a week?



hCG 1000iu in a single shot is not recommended imho
I have studied this based on aas user guys experiences.
1000iu shot may affect your libido in a negative way.
250iu X 2 a week is standard protocol and same is in practice presently.
this is my view though …some one more experienced can put more light on the topic.


Why is the 1000iu shot not recommended? If this dual-peak is in fact true it makes sense to do a single shot.
I think this 1 shot protocol would avoid leydig cell desensitisation (if it exists) but it all depends on the truth behind the science of that double-peak.



I wouldn’t put too much stock in that advice. That particular post has been quoted since at least late 2010, and there is no “Endocrinology Society”. There is the Endocrine Society, and there is Society for Endocrinology, and the American Association of Clinical Endocrinologists, not to mention the Pediatric Endocrine Society, but no Endocrinology Society.

I also can’t seem to find the original research article using phrases out of that post to search with. There’s no citation provided so I am not going to dig through 26 million citations in pubmed to try to find the original deal.

One big shot a week used to be the protocol, but that was years ago and I have to think that the standard protocol for clinical patients has changed for a reason. currently the protocol is shots of 250 IU taken either 2x a week or 3x a week. In rare cases one of my older 55 year old training clients was prescribed EOD (not by me, by his doctor).

Bottom line, there’s no real reason to think protocol should be changed back 6+ years.


It is also worth noting that as the original poster (whoever it was) writes “The second phase of testosterone secretion after hCG but not LH is
associated with the longer half-life of hCG in comparison to LH”…if this is true it is likely only because of the large initial dose. Shut down is more likely to occur with a large persistent dose that hangs around setting off negative feedback systems than much smaller doses that are cleared quickly.

Of course it is impossible to say because the guy never put a citation down so you could check up on the article.


I have seen 2 live cases where 1 guys were taking 1000IU shot in one go and another guy was taking 2000IU in one go. Both were into initial phase of cycle. They observed big crash on libido that it lasted till PCT. and in PCT they had zero libido. the reason behind taking 1000/2000IU was only convenience since hCG comes in 1000/2000 IU vials.

u may try it out if u want though since everyone is different n it might happen it suits u.


Many thanks for your reply Aragorn. I was slightly cautious about the article too as I could not locate the source either. It is from another BB website and that post has been ‘stickied’ so for them it must be gold standard.

On a seperate note, I have come across a protocol suggesting low dose Nolva on cycle to prevent hCG-induced leydig cell desensitisation. Anyone heard anything about this?
Is it worth 20mg nolva EOD on top of AI?



Interesting, thank you for your input. I do not think I will be blasting hCG any time soon.



I wasn’t aware of any actually data that supports leydig cell desensitization from HCG use, especially when used at low dose of 250-500iu. For these doses i think there is some clinical data in support of no leydig cell desensitization.


Yeah I’m not aware of any either. Considering hcg used for HRT purposes seems to work just fine on a continuing basis I don’t think it’s a worry at the leydig cells. If it were you would see little clinical application


I agree, I remember VTBalla also used to say that leydig cell desensitisation was mainly bro-science. I guess he was right.



nice to have you back, SB.

Personally I use my hCG at 500iu twice weekly, the day after my test injections (when using long esters).

I do it because Dante says to do it that way, and I do more or less everything Dante tells me to.


So you’re on 1000iu a week?

I do a twice a week shot too, Tuesday and Friday.
Everything I do is on those 2 days. So on each day I do 250mg Test E, 250iu hCG and 0.25mg adex (and 60mg Dbol ED). Not a problem is it?
Might drop the adex though, feel as though I dont need it. I’ve needed it as this dose in the past but im currently pretty lean so it may be overkill.