Ask CLYR: CLYR offers low-dose naltrexone as a 4.5 mg capsule, taken nightly or as your provider directs. 4.5 mg is the dose used in several published LDN trials, which is a research convention, not a promise of results. A licensed provider decides whether it is appropriate for you.
Low-dose naltrexone (LDN) is a compounded capsule, not FDA-approved at this dose, and prescribed off-label. Dose is one of the most searched questions about it, partly because online forums trade very different numbers. This article explains the one strength CLYR offers, how it lines up with the doses used in published research, and why the decision belongs to your provider. For the basics, start with what low-dose naltrexone is.
The short answer
CLYR offers one strength: 4.5 mg capsules, taken nightly or as your provider directs. A licensed provider reviews your health history and medicines and decides whether LDN is appropriate for you. The directions are on your pharmacy label and in your patient portal.
Why 4.5 mg
4.5 mg is the low dose CLYR offers, and it is the dose used in several published LDN trials, including a multiple sclerosis trial by Cree and colleagues (2010), a fibromyalgia trial by Younger and colleagues (2013), and a 12-month fibromyalgia trial by Rodríguez-Freire and colleagues (2026). A dose-finding study by Bruun-Plesner and colleagues (2020) estimated that half of participants responded at about 3.88 mg and 95% at about 5.40 mg, and the authors wrote that 4.5 mg "seems to be a relevant test dose".
That is a research convention, not proof that the dose works. The 4.5 mg trials had mixed results, and the 2026 trial did not find a clinically meaningful benefit over placebo. It is also a small fraction of the standard FDA-approved 50 mg tablet, which is explained in LDN vs the standard 50 mg tablet.
Doses used in published studies
This table is background on what researchers tested. It is not a dosing guide, and the results column is there so no dose reads as a promise.
| Study | Condition | Dose | Result |
|---|---|---|---|
| Cree et al., 2010 | Multiple sclerosis | 4.5 mg nightly, 8 weeks | Better mental health quality of life scores; small and short |
| Younger et al., 2013 | Fibromyalgia | 4.5 mg | Pain scores down 28.8% vs 18.0% on placebo; 31 people |
| Bruun-Plesner et al., 2020 | Fibromyalgia | 0.75 to 6 mg, dose-finding | Estimated response doses only, not efficacy |
| Due Bruun et al., 2024 | Fibromyalgia | 6 mg | Not better than placebo for pain |
| Rodríguez-Freire et al., 2026 | Fibromyalgia | 4.5 mg, 12 months | No clinically meaningful benefit over placebo |
| O'Kelly et al., 2022 | Long COVID | 1 mg, then 2 mg | Self-reported improvements; no comparison group |
| Byambasuren et al., 2026 | Long COVID (review) | 1 to 6 mg across studies | Low certainty evidence |
More on the fibromyalgia trials is in LDN and fibromyalgia: what the trials found.
Gradual dose increases in research settings
Some studies started below 4.5 mg or stepped the dose up during the study. O'Kelly and colleagues (2022) used 1 mg for the first month and 2 mg for the second, and the Bruun-Plesner dose-finding study moved participants up and down between 0.75 and 6 mg. That is research background only. CLYR offers 4.5 mg capsules only and does not sell lower strengths or titration packs.
How it is taken at CLYR
One 4.5 mg capsule nightly, or exactly as your provider directs. Your directions are printed on the pharmacy label and saved in your portal, and your provider sets the days of supply. If a side effect such as vivid dreams bothers you, tell your provider rather than changing anything on your own; see LDN side effects.
Price
At CLYR, low-dose naltrexone 4.5 mg is $119 for 30 capsules or $169 for 90 capsules. Each order is billed once and nothing renews. Provider review and shipping are included, and your provider sets the days of supply. See low-dose naltrexone 4.5 mg at CLYR.
Frequently asked questions
What dose of LDN does CLYR offer?
One strength: 4.5 mg capsules, taken nightly or exactly as your provider directs.
Why 4.5 mg?
4.5 mg is the low dose CLYR offers, and it is the dose used in several published LDN trials. Those trials had mixed results, so your provider decides whether it is appropriate for you.
Does CLYR offer lower starting doses?
No. CLYR offers 4.5 mg capsules only. Some research studies used lower or stepped doses, and your provider can talk through that background with you.
Should I take LDN at night?
Many studies and providers use bedtime dosing. Follow the directions your provider writes, which are on your pharmacy label. If sleep changes bother you, see LDN side effects.
How much does it cost?
$119 for 30 capsules or $169 for 90 capsules, billed once. Nothing renews, and your provider sets the days of supply.
Important safety information
Compounded low-dose naltrexone is a prescription capsule dispensed only after a licensed provider independently reviews your intake and determines it is appropriate for you. Do not take naltrexone if you take any opioid medicine or have taken one in the last 14 days, including tramadol, codeine, methadone or buprenorphine, because naltrexone blocks them and can cause sudden withdrawal; do not take it if you currently take or need opioid medicines, have liver disease, hepatitis or abnormal liver tests, or are allergic to naltrexone. Tell your provider about kidney disease, pregnancy, breastfeeding or plans for pregnancy, and about every medication and supplement you take. Side effects may include vivid dreams, trouble sleeping, headache, nausea, dizziness or anxiety. Carry a note that you take naltrexone, because opioid pain medicines may not work normally while it is in your system. Compounded medications are made by a licensed U.S. 503A pharmacy to a provider's prescription; they are not FDA-approved and have not been reviewed by the FDA for safety or effectiveness. Individual results vary. Not everyone qualifies. This page is informational and is not medical advice. Call 911 in an emergency.
The same text appears in the Important Safety Information on the LDN page.