One of the most common questions I get from patients and practitioners alike is:

"What dose of LDN should I start with?"

It's a fair question. And for years, the standard answer has been some variation of "start low and go slow" or "work up to 4.5 mg." But after two decades of prescribing low-dose naltrexone, I've come to realize that this one-size-fits-all approach fails about a third of my patients.

Here's the uncomfortable truth: approximately one-third of patients don't respond to standard LDN protocols. Some of them aren't actually non-responders—they're people who started at a dose that was wrong for their body. They got side effects, felt worse, and gave up before LDN ever had a chance to work.

I want to change that.

Why Starting Dose Matters

LDN works by temporarily blocking opioid receptors, which triggers your body to produce more endorphins and become more sensitive to them. But here's the catch: if your endorphin reserves are already depleted from chronic illness, stress, or prolonged suffering, even a "low" dose can feel like too much.

Think of it like asking someone who hasn't eaten in three days to run a marathon. Their body doesn't have the reserves. They need to rebuild first.

I call this concept endorphin reserve assessment—estimating how much your body's natural opioid system can handle before we ask it to do more.

The Endorphin Reserve Score: A Simple Assessment

Over the years, I've developed a quick scoring system to help guide starting doses. It's not perfect, but it's practical. Answer these three questions honestly:

Question 1: Are you medication sensitive?

Do you tend to react strongly to medications? Do you need lower doses than most people? Do you get side effects that others don't seem to experience?

No → Score: 0

Yes → Score: 10

Question 2: Are you highly functional in daily life?

Can you work, exercise, manage household tasks, and maintain social connections without significant difficulty? Or does your illness severely limit what you can do each day?

No (limited function) → Score: 10

Yes (functioning well) → Score: 0

Question 3: Have you been ill for more than 6 months?

Chronic illness depletes endorphin reserves over time. The longer you've been struggling, the more cautious we need to be.

No (less than 6 months) → Score: 0

Yes (more than 6 months) → Score: 10

Your Starting Dose Based on Total Score

Add up your scores from all three questions:

© Kim LDN Optimal Dose Questionnaire™

© 2025 Yoon Hang Kim, MD. All rights reserved. This questionnaire is copyrighted material and may not be reproduced, distributed, or transmitted in any form without express written permission from Yoon Hang Kim, MD.

The Exception: When You're Feeling Exceptionally Well

If your score is 0—meaning you're not medication sensitive, you're highly functional, and you haven't been ill for more than 6 months—you may be able to start at conventional doses:

1 mg – A conservative starting point for mild immune modulation or preventive use

3 mg – A middle-ground dose that many providers recommend

4.5 mg – The "standard" LDN dose often cited in research

However, even if you qualify for higher starting doses, there's no harm in starting lower. You can always go up. You can't un-take a dose that made you feel terrible.

Real-World Application

Let me walk you through a few examples:

Patient A: A 45-year-old woman with fibromyalgia for 8 years. She's highly medication sensitive—even half doses of most prescriptions cause side effects. She's unable to work and struggles with daily activities.

Medication sensitive? Yes → 10

Highly functional? No → 10

Ill more than 6 months? Yes → 10

Total: 30 → Start at 1 microgram

Patient B: A 52-year-old man with Hashimoto's thyroiditis diagnosed 2 years ago. He's not particularly medication sensitive, works full-time, and exercises regularly despite some fatigue.

Medication sensitive? No → 0

Highly functional? Yes → 0

Ill more than 6 months? Yes → 10

Total: 10 → Start at 100 micrograms

Patient C: A 38-year-old woman interested in LDN for immune support. No chronic illness, no medication sensitivities, fully functional.

Medication sensitive? No → 0

Highly functional? Yes → 0

Ill more than 6 months? No → 0

Total: 0 → May start at 1 mg, 3 mg, or 4.5 mg

Titration: The Path Forward

No matter where you start, titration is key. Here's my general guidance:

For those starting at microgram doses: Increase every 2-4 weeks, doubling the dose each time (1 mcg → 2 mcg → 5 mcg → 10 mcg → etc.)

For the most sensitive patients: Some need 1-3 months between dose changes

Goal dose: Usually 1.5 to 4.5 mg, though some patients do well at microgram doses indefinitely, and others need higher doses (up to 6 mg or beyond for certain conditions)

Listen to your body. If a dose increase causes sleep disturbances, vivid nightmares, or worsening symptoms, back down and stay longer at the previous dose.

Why This Approach Works

The standard "4.5 mg for everyone" protocol assumes a baseline level of physiological reserve that many chronically ill patients simply don't have. By matching the starting dose to the patient's actual capacity, we:

1. Minimize side effects that cause people to abandon treatment

2. Allow the endorphin system to rebuild gradually

3. Create a foundation for sustainable improvement

4. Honor the principle of hormesis—where the right dose heals and the wrong dose harms

A Note on Compounding

Microgram and nanogram dosing requires a compounding pharmacy familiar with LDN. Not all pharmacies can reliably produce doses this low. Work with your prescriber to find a reputable compounder, or ask about self-dilution protocols if necessary.

The Bottom Line

LDN is a powerful tool—but like any tool, it works best when used appropriately. The question isn't just "Should I try LDN?" but "What's the right dose for me?"

Take the assessment. Know your score. Start where your body needs you to start—not where a protocol tells you to start.

That's honest medicine.

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Dr. Yoon Hang Kim is a board-certified preventive medicine physician specializing in integrative and functional medicine. He has been prescribing LDN for over two decades and has presented at multiple LDN Research Trust conferences internationally. He practices telemedicine through Direct Integrative Care, serving patients in Iowa, Illinois, Missouri, Georgia, Florida, and Texas.

Learn more at directintegrativecare.com

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Disclaimer: This article is for educational purposes only and does not constitute medical advice. LDN requires a prescription and should be used under the guidance of a qualified healthcare provider. Always consult with your physician before starting or modifying any treatment regimen.