Feb 14, 2026 10:30 am FB Live Session

What I’ve Learned from Two Decades of Prescribing Low Dose Naltrexone

By Yoon Hang Kim, MD, MPH

www.directintegrativecare.com

I had a conversation with my LDN community recently—a live session where people brought their real questions, their real frustrations, and their real experiences with Low Dose Naltrexone. And I want to share some of what came up, because I think it’s important for anyone on LDN, or considering it, to hear this from a practitioner who’s been in the trenches with this medication for over twenty years.

This isn’t a polished lecture. It’s more like pulling up a chair and talking through the stuff that matters—the side effects nobody warned you about, why some people struggle more than others, and what I actually do in my own practice when things get tricky.

“Why Am I Feeling Worse Before I Feel Better?”

One of the most common questions I get goes something like this: “I started LDN and felt great for a week or two. Then the anxiety kicked in. Or I got irritable. Or I just felt… down. What’s happening?”

Here’s what I think is going on, and it goes back to something I call endorphin depletion.

When you take LDN, you’re temporarily blocking your opioid receptors. The idea is that your body responds by making more endorphins—your natural feel-good molecules. But here’s the thing nobody talks about enough: if you’re already depleted, if your body has been running on fumes for months or years because of chronic pain, autoimmune disease, or just the sheer weight of being unwell—then that blockade hits differently.

Your body needs time to catch up. And during that gap, you might feel grumpy. Irritable. Anxious. Emotionally flat. That’s normal. It doesn’t mean LDN isn’t working. It means your endorphin system is recalibrating.

Endorphins: The Neurotransmitter Nobody Talks About

We hear a lot about serotonin and dopamine. And they’re important—don’t get me wrong. But I think the best way to understand endorphins is that they sit somewhere between serotonin and dopamine. They give you happiness and pleasure. They give you that natural high people talk about. They’re not technically neurotransmitters, but they function like them in a very real way.

So when your endorphin system is under stress, and your serotonin system is already struggling, and your dopamine is running low—well, the symptoms you’d expect from any of those deficiencies can get triggered. Emotional distress. Anxiety. Depression. Fatigue. It’s all connected.

Our bodies are incredibly, amazingly smart. We’ve got multiple systems running in parallel, and endorphins are one of the most powerful tools we have. When we support them properly, the results can be remarkable.

How I Assess a Patient Before Starting LDN

In my practice, before I even write the prescription, I’m asking myself a few key questions about the person sitting in front of me:

Is this person endorphin depleted? Have they had their condition for a long time? Are they sensitive to medications in general? And most importantly—what’s their vitality like?

By vitality, I mean something very specific. When you wake up in the morning, do you have energy to face the world? When you come home tired, do you still have something left for the things you love? Or are you just surviving between doctor’s visits?

If the answer is that someone is depleted, sensitive, has been struggling for a long time, and their vitality is low—then my experience tells me that person may benefit from the lowest dose that can be compounded. What the literature calls ultra-low dose naltrexone. I’ve published a paper with my team at the University of Kansas on this approach, and it’s available for free on my website. www.yoonhangkim.com

Why I Use Ultra-Low Dose Naltrexone

There are three main reasons I start patients on ultra-low dose naltrexone.

The first is children. All pediatric patients, I prefer to start low. Those of you who have children know that our attachment to our kids is deep, and having a medical issue with a child is a different level of suffering. I want to be careful.

The second is people who are very sensitive—people who’ve had side effects from LDN in the past. I recommend they restart at the lowest possible dose.

The third is patients on opioid medication. That’s another scenario where starting at the lowest possible dose just makes sense.

And I know this isn’t popular advice. We all want results right away. But in my experience, low and slow wins.

My “Rechallenge” Approach to Side Effects

I’ll share something personal. When my own neuropathy came back—and it was very unpleasant—I did something I don’t usually recommend to patients. I pushed through to get to an effective dose faster. I took the dose, then took a day or two off. Rechallenged. Took another break. Rechallenged again.

By the end, I was able to take about four times the amount I’d started with, and I got really great results. But I’m a physician who understands the pharmacology. For my patients, I recommend a gentler version of this same principle: if you have side effects, take a little break. Let your endorphins rebuild. Then try again.

The common side effects I see in practice include headaches, nausea, malaise, feeling overstimulated, night sweats, and increased gut motility—needing to go to the restroom more often. That last one is actually related to why LDN works for SIBO: it speeds up gut function.

In my own experience, when my dose is too high, I get nauseous and feel a general malaise—just unhappy. My side effects typically last one to two weeks. For most people, if the dose is reasonable, these effects resolve. But if they don’t, always talk to your doctor.

Can You Take Dopamine Supplements with LDN?

I get this question a lot. The short answer is yes, people do combine dopamine-supporting supplements with LDN. I use LDN for patients with Parkinson’s disease, and they’re already on dopamine medications. I have other patients taking supplements with dopamine precursors like tyrosine, and they do fine.

But if you’re thinking about adding anything to your regimen, talk to your prescribing doctor. This isn’t a one-size-fits-all situation.

What About Liver Enzymes?

I’ve written a blog article on this topic, and my bottom line is: I don’t think we have to worry about it. But if you’re a provider, it’s always a good idea to check a complete metabolic panel. It’s not expensive, and it gives you a lot of useful information. Responsible medicine means we check.

A Quick Word on Trigeminal Neuralgia

I want to mention this because it’s a condition that responds particularly well to LDN in my experience. Trigeminal neuralgia is terrible—truly terrible pain. And in my practice, perhaps eighty percent of people with trigeminal neuralgia could say LDN made it better. That’s a remarkable response rate for a condition that’s notoriously difficult to treat.

The Honest Truth About LDN

I’m not here to tell you LDN is a miracle drug. What I am here to tell you is that it’s a powerful tool—one that works through a mechanism unlike almost anything else in medicine. It asks your body to do more of what it already knows how to do.

But it requires patience. It requires the right dosing. It requires a doctor who understands the nuances. And sometimes, it requires starting over at a lower dose and working your way back up.

If your doctor has left it entirely up to you to figure out your LDN dosing—I’ll be honest, I think that’s a bit of a cop-out. If a doctor writes the prescription, they’re responsible for guiding the patient. And if they don’t want to do that, the right thing is to refer you to someone who will.

You deserve a partner in this process. Don’t settle for less.

About the Author

Yoon Hang Kim, MD, MPH is a board-certified physician specializing in integrative and functional medicine. A graduate of Dr. Andrew Weil’s Integrative Medicine Fellowship at the University of Arizona, Dr. Kim has been practicing integrative medicine since 1999. He is recognized internationally as an expert in LDN therapy, having authored two books on Low Dose Naltrexone, published peer-reviewed articles on chronic pain management, and presented at multiple LDN Research Trust conferences.

Dr. Kim practices virtual telemedicine through Direct Integrative Care, serving patients in Iowa, Illinois, Missouri, Georgia, Florida, and Texas. His clinical focus includes autoimmune disorders, chronic pain, fibromyalgia, MCAS, Long COVID, and integrative oncology.

Clinical Services: www.directintegrativecare.com

Educational Resources: www.yoonhangkim.com

YouTube: youtube.com/@YoonHangKimMD

LDN Support Group: ldnsupportgroup.org

Disclaimer: This blog post is for educational purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider before starting or modifying any treatment regimen.

© 2025 Yoon Hang Kim, MD, MPH | Direct Integrative Care