Humalog, I find it will hit me twice, two waves. One 45-60 minutes into it, and another anywhere from 90-120 minutes later.
Usually I find I can pass that first wave and not feel it, if I can get a good meal in before that 2nd wave hits me I am in the clear.
The "wave" is usually misunderstood to mean something it isn't. The entire idea of waves got started because after injecting Humulin, people would feel their BG drop, eat, then feel fine for a while, and then feel their BG drop again. This led people to believe that their insulin was being released in "waves".
Or, in your case, you would inject Humalog, escape the first wave without eating and still feel fine, then get hit by the 2nd wave if you didn't eat soon enough and feel your BG drop.
In reality, when injecting Humulin or Humalog, the insulin from the injection enters the bloodstream at roughly the same rate from beginning to end. there is no significant "wave" in which a blast of insulin is released in the beginning and then another blast later on.
So, what is going on then? In your case, you did not feel the Humalog for the first 90-120 minutes not because you escaped the first "wave" but because you simply had enough currently circulating BG present to keep your BG levels in a normal range for the first 90-120 minutes. But, by the time you reached 90-120 minutes, the Humalog had burned through currently circulating BG and it was at that point that you began to feel symptoms of hypoglycemia. there was no "2nd " wave, circulating BG levels just ran low.
The Humalog had been chomping away at BG levels the entire time within minutes of first injecting it--you just didn't feel it until your current BG was no longer adequate to maintain normal BG levels.
With Humulin, its the same principle, but since it's longer acting, people think the waves come at different times. there are no significant waves--the insulin from the Humulin releases at a pretty steady pace the entire time. Remember, it regular Humulin insulin. There is nothing within it which cases absorption to be delayed at certain points post-injection.
Let's say someone takes humulin and gets hypo symptoms 2 hours in. At that point they eat and feel better. Why do they sometimes have another hypo episode? Well, if the food they ate is only capable of maintaining BG for a few hours, the insulin will still be present after the BG from that meal was used up, resulting in more hypo symptoms. There was never a "2nd" wave.
Whether or not someone feels one "wave" or two "waves" or no "waves" at all will depend on what and how much they eat, not on some wacky release pattern in which the slin is released in waves. This is why some guys can eat one huge meal before an injection of humulin and never feel a thing...because they ate a meal which was able to maintain adequate BG the entire time the slin was active. But, if someone doesn't eat enough, or they eat only fast digesting carbs, BG may drop once or even twice during the slin's active life, leading them to believe that the drop(s) in BG they feel is due to the slin being relegated in waves.