I know this is an older thread but I really wanted to share some tips and knowledge from my perspective as a gastroenterology nurse who works with patients dealing with this and has for years. There is a lot of bad information about constipation out there and it can be pretty harmful so I want to try and debunk some of the things you've already been told and just give you more information about how to use these products.
Most of the issues that I see people have with constipation on GLP-1 medications could be majorly helped if not entirely solved by improving diet and exercise. Exercise helps get the bowels moving and a good diet that has a variety of fruits and veggies and whole grains in it will help keep things regular as well. Diets heavy in things like junk food and red meat will stop the bowels right up. The other big one that I see a lot with GLP1 medicines is that people simply don't eat enough and then think that they're going to still have normal bowel movements; you have to eat to have something to poop out 🤷♀️.
There are two types of fibers: soluble and insoluble. Most people are only really familiar with insoluble fiber and they think that that's what you need to help you have bowel movements, but if you're facing constipation and slow down like with a GLP medicine, insoluble fiber is the worst thing you could do for yourself. All insoluble fiber can do is add bulk to your stool; this will only make constipation worse. Insoluble fiber is fiber that the body cannot break down at all so it just goes right through and becomes part of your stool. This is found in things like vegetables and the skin of fruits like apples.
Soluble fiber is magic. It can be broken down by the body and so if your stool is too hard and gets stuck like what happens with constipation, soluble fiber will pull water in to make it softer and help it move along the tract easier. If your stool is too loose and watery, soluble fiber will bulk it up and help make it more solid. Soluble fiber is what you should be targeting, and you'll get it through the flesh of fruits and in whole grains. But, if you increase your soluble fiber intake without increasing your usable fluid intake, then your bowels don't have any liquid to pull into help soften up your poops and so it can just make constipation worse. This is how people take fiber supplements and fiber gummies and end up in the ER with bowel impaction. It's worse than if they had never done anything at all. You have to increase your clear liquid intake if you are going to add fiber to your diet in any way. Pepsi, tea, coffee, dark sodas/drinks will not help you.
If you don't want to add fiber into your diet naturally, you can always use fibercon, citrucel, konsyl, metamucil, etc. Tons of good options on the market. Just make sure you also increase your clear liquid intake!
So that's types of fiber, why you want it, and how you should be getting it. Now for laxatives.
You basically do not want to be using any kind of laxative long-term. If you absolutely have to, then you want to choose an osmotic laxative and not a stimulant laxative. The person who said that Miralax (PEG 3350) is the safest laxative to use long-term is 100% correct. Everything else should be a short-term thing to help you go in rare cases where you can't make it happen otherwise or you're getting too uncomfortable to wait. That includes Senna, dulcolax, magnesium supplements, etc. What these things can do is to create a dependency from your GI tract on extra stimulant in order to make the muscles move so that you go poop. That's a very terrible thing over time because your body will get used to the medicines and your tolerance will go up and then there won't be enough medicine that you can safely take in order to make you have a bowel movement. I have seen so many patients in our GI clinic for a study called anorectal manometry where we test the muscle function of the rectum, and a vast majority of the people needing this study for uncontrollable constipation are people who have abused laxatives for a long time. There is no fix for these people. They are beyond where medicine can help them, and their bowels don't function normally anymore. These people are literally having to put their own fingers into their rectum and physically pull their poop out because they don't have muscle contraction anymore to do that for them. You do not want to end up like these people.
I am very prone to constipation anyway, so I am careful about what I do with my GLP1s and part of my titration of my medicines is considering how often I'm able to have a bowel movement without needing to use anything other than soluble fiber. I take three citrucel methylcellulose fiber caplets every day, drink plenty of water, eat a good amount of fruits and whole grains, and still need 1-2 doses of Miralax per week to keep things moving. Me personally, I'm not comfortable going above that amount. I have seen patients who take Miralax every single day of their lives and cannot have bowel movements without it and yet have not built a tolerance to it so that they are in an impossible situation. But, I didn't want that to be me. 2.5 mg semaglutide caused me to need to take Miralax almost every day in order to stay regular, which was a big part of the reason why I didn't stay on that as my primary GLP1 for very long. I also used to keep Fleets enemas around to help when I was on sema alone; these aren't that bad, but efficacy long term isn't nearly as well studied as Miralax so I would still put these in the "rarely use this" category.
Sorry this was so long. I just feel like there's a level of detail and importance in this that a lot of people don't get and it's pretty vital to know how these options actually affect you long term.
