Some good info I've found...

"Exogenous 20K Growth Hormone (GH) Suppresses Endogenous 22K GH Secretion in Normal Men" Y. Hashimoto et al. 2000

It is of special interest since the experiment was done on 32 HEALTHY adults aged 20-31.

OK, the key findings which contradicts much of the hype around hgh:

*Exogenous hgh administration (sc) will not supress endogenous hgh production before 4 hours after administartion.

*IGF levels will raise slowly in 12 hours after administartion and then raise rapidly and reach a peak about 24 hours after administration.

*Exogenous hgh administration will supress endogenous hgh prduction for about 24 hours. This did even occur at small doses of 1-2iu a day.

*HGH is very dose dependant. A 10iu dose will give a ten fold increase in peak concentration levels of both hgh and igf-1. Also a bigger dose will not increase the supression time or peak times.

In regard to timining of hgh injections this would mean that the best time to inject your hgh is just before you go to sleep. That way you will still get your largest endogenous pulse, which accours about 2 hours after you go to sleep, and when that pulse is over, a little later in about 4 hours you hgh levelse will reach another peak from the hgh administration. The supression of your own hgh will be finished by the time you do your next injection the day after at the same time, so you will still get the deep sleep pulse the night after.

By taking your shots am you will supress all endogenous production of hgh the following nigth. Forget thinking that going up taking your shot 4am or 7am will help you not supress your own production, you will be shut down for 24 hours.

By doing several injections each day like am/afternoon you will shut down your own production completly(if you do ed shots)

The results also contradicts the theory of the hgh 3x blasting method popular for mass gaining. The key there is to maximize igf levels after training,
taking your shots pwo. The shots is supposed to be taken IM. Well first IM shots is not absorbed as good as sc shots, and you will get a somewhat better peak in concetration levels but a somewhat faster half-life time.

Anyway your igf levels will not peak before at least somewhere between 12-24 hours later and the whole dose will be less absorbed. The insulin levelse from your IM slin shot pwo will in no way have any synergy with a pwo hgh shot, because of the delayed increase in igf-1 levels. If you train mon-wed-fri with the 3x blast method your igf levels-1 will be at top the day after when your not training. It's quite important to see the difference between hgh peak time and igf peak time from hgh administration, as their are very different.

All in all bearing in mind that endogenous hgh production in healthy adults range from 0,5-1,5iu daily(I think), it is not that much you loose from beeing completly shut down. But even at larger doses of up to 10iu it should still be no loss of effect to take your hgh dose in one shot. If you take it before bed you igf levels will increase stadily the day after and be in high concetration when you train in the afternoon or evening.

If your concern is pinning and maintaining a proper sleeping schedule to induce natty secretion then...

I've been thinking a lot about this kind of question recently. I have noticed a difference between keeping a stable sleeping schedule where i go to sleep around 11pm, wake up at6am and pin. On that schedule, i feel good and have nice dreams and other sides are great. . I think my natty gh is firing during sleep. I also don't eat carbs after 6. However, on many weekends i sleep much later and still wake up and pin at 6. On those days, i don't feel as good and it's not bc i'm drinking. I've tried to adjust the time but no beneficial results. This is just bro-science but my conclusions are i'm not getting much natty secretion when i go off a tight schedule. Could be bc i'm 49 and getting little anyway.

I am going 4 pins and one day off at 2.5. I will try 3.33 x 3 and one off. I'm concerned with keeping my natural going and the doses are low so i'm not going to pin twice. However, i may in the future.

You could fit your 8 night into off days depending on the spacing or you could pin twice a day if you are not concerned with natty and your doses are high.