@MrsNoobie, welcome to the TuDiabetes forum! There’s a lot to learn in the beginning and if you play it right, you’ll never stop learning.
In order to understand your insulin needs you’ll hear mention of the terms basal and bolus. In between meals and during long periods when you’re not eating, like when you’re sleeping, your body, especially your brain needs a constant supply of glucose. Luckily the body has figured out how to store glucose in readily available places.
The liver has a large store of glucose that can be shifted out during periods when there is no food digesting. The body still needs insulin to metabolize that glucose. In response to that need, a non-diabetic pancreas will secrete small pulses of insulin to satisfy that requirement. This is called basal insulin. So, as a person with diabetes, you need to replace this long acting slow delivery insulin.
The intermediate-acting insulin part of your insulin dose, the 75% portion, especially when taken twice per day provides this function. Each of your 20 units doses delivers 15 units of the intermediate insulin that acts as basal insulin.
The other 5 units of each dose, the 25% portion, is the rapid-acting insulin intended to metabolize meals. The meal insulin is often describe as the bolus insulin.
One of the disadvantages of the fixed 75/25 intermediate/rapid-acting mix is that you might find it difficult to balance both the basal and bolus needs well. To get enough bolus insulin for a meal may mean taking more of the longer acting component than you’d like or need.
To make matters more complicated, intermediate acting insulins often play a dual basal/bolus role. You take one morning and one evening dose but no injection for lunch. That lunch is covered by the intermediate portion of your breakfast dose that conveniently peaks around lunchtime. So, don’t miss your mid-day meal or you might go low!
As others have suggested, you will learn your personal metabolism more quickly if you can keep some notes on insulin dose size, dose timing before eating, and the kind and amount foods that you eat. Checking your glucose with a fingerstick meter at mealtime and few hours later will give you an idea how well things are working.
You are learning about your own unique metabolism here, so it is valuable information! You will not metabolize the same meal the same way each day. In fact, the time of day will affect your food metabolism. You don’t have to write stuff down but you will learn more quickly if you do.
There’s a lot to learn here. You don’t have to learn it all at once. Learn a little bit each day. It will add up to a lot over time.
Every insulin formulation comes packaged with a printed insert of information about the insulin. It may seem overly technical at first but it’s worth it to at least skim through it so you know what it generally covers. Here’s the Humalog 75/25 Mix package insert.
Good luck and please return with questions!
