Human Medicine
Naltrexone is an FDA-approved opioid antagonist, used at 50mg daily for opioid use disorder and at 380mg (as an injection) for alcohol use disorder. “Low dose naltrexone” refers to doses far below that — typically 0.5mg to 4.5mg — an off-label use with no FDA-approved indication. At these low doses, researchers have observed different pharmacological effects than at the approved dose, and interest in LDN has grown across pain management, rheumatology, gastroenterology, and integrative medicine.
Medically reviewed by Vincent Meo, RPhPharmacist · Last reviewed October 2, 2026Some LDN subscription services lock you into recurring monthly billing that renews automatically. CareFirst Specialty Pharmacy charges one flat price for a full 90-day supply — no auto-renewal, no surprise charges.
Typical Subscription Model
$25/mo
Billed monthly, auto-renews
CareFirst Specialty Pharmacy
$51.95/ 90-day supply
Flat price per fill, refill only when you need it
A 90-day supply is $23.05 less than the equivalent subscription cost, and over 6 months (two 90-day fills) you'd pay $103.90 instead of $150 — a savings of $46.10, with no recurring commitment.
Our pharmacists Michael Vuong, RPh; Charles Glatz, B.S.Pharm., CCP; and Vincent Meo, RPh answered LDN questions from patients and medical professionals live with the LDN Research Trust. The recording is normally $20 — use our code at checkout and it's free.
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Available only through compounding.
Because no commercial manufacturer produces naltrexone at these low strengths, LDN is available only through compounding. CareFirst Specialty Pharmacy is a PCAB-accredited compounding pharmacy and an LDN Research Trust member, preparing patient-specific LDN in the strength and dosage form your prescriber orders — tablets, capsules, sublingual tablets, oral suspension, or topical cream.
LDN is prescribed off-label. It is not FDA-approved for any of the conditions discussed on this page. All compounded LDN requires a valid prescription, and whether it’s appropriate for you is a decision for you and your prescriber.
Naltrexone blocks opioid receptors. At the 50mg dose used for addiction treatment, that blockade is sustained and full. At low doses, researchers have proposed a different mechanism: a brief, partial blockade — often described as occurring for a few hours after a bedtime dose — that some researchers hypothesize triggers a rebound increase in the body’s own endogenous opioids (endorphins). Separately, naltrexone at low concentrations has been studied for effects on toll-like receptor 4 (TLR4) signaling in glial cells, a pathway implicated in neuroinflammation and central sensitization, as well as in other cells such as mast cells to modulate immune response.
These are proposed mechanisms under active study, not settled science. The exact mechanism of any benefit patients report is still being researched, and mechanism plausibility is not the same as proven clinical benefit.
LDN has no FDA-approved indication. Everything below describes off-label research interest and published evidence — not treatment recommendations. Evidence quality varies significantly by condition, and even where positive results have been reported, most studies are small, and larger confirmatory trials are often lacking or, in at least one case, have not confirmed earlier findings.
Some conditions circulate in LDN patient communities — including ALS, Alzheimer’s disease, Parkinson’s disease, autism, and use as an “anti-aging” agent — where published clinical evidence in humans is minimal to nonexistent, largely preclinical, or drawn from isolated case reports. We’ve removed these from the page rather than imply a level of evidence that doesn’t exist. If your prescriber is considering LDN for one of these situations based on your specific case, that conversation belongs with them or call your compounding pharmacist to go over proposed guidelines — not with marketing copy.
LDN is most often prescribed as an adjunct — alongside the conventional treatments a patient’s condition already calls for — not as a replacement for disease-modifying therapy, immunosuppressants, or other standard-of-care treatment. One exception: naltrexone blocks opioid receptors, so it cannot be used together with opioid pain medications. Patients taking opioids or in opioid use disorder treatment must have those medications fully out of their system, under medical supervision, before starting naltrexone at any dose — otherwise it can precipitate acute withdrawal.
Tablets are compounded with fewer ingredients than capsules and without calcium, gluten, lactose, corn, dairy, soy, or dyes.
To process your order we will require a prescription from you or your prescriber. We will only compound and dispense upon receipt of a valid patient specific prescription.
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Our team can coordinate with your provider to get what you need quickly.
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CareFirst Specialty Pharmacy is proud to be an LDN Research Trust 2026 member.
LDN’s published safety data generally describe it as well-tolerated in the studies conducted to date, with the most commonly reported effects being vivid dreams and disrupted sleep, particularly when starting therapy — these often lessen over the first one to two weeks as the body adjusts. As with any medication, individual reactions vary, and long-term, large-scale safety data at these doses is more limited than for widely used, FDA-approved therapies.
Precautions:
Always tell every prescriber and pharmacist about all medications you take, including LDN, before starting anything new.
Depending on your prescription and sensitivities, LDN can be compounded with fillers including:
Your prescriber and our pharmacists can discuss which filler fits your sensitivities and dosage form.
Hear more about how LDN is compounded and how our team supports you through prescription and refills.
Explore strengths, fillers, and dosage forms tailored to your prescription.
Naltrexone is an FDA-approved opioid antagonist. At low doses (0.5mg–6mg), it is prescribed off-label and has been studied for potential analgesic and anti-inflammatory effects not observed at higher doses. Available with a valid prescription.
Naltrexone is an FDA-approved opioid antagonist. At low doses (0.5mg–6mg), it is prescribed off-label and has been studied for potential analgesic and anti-inflammatory effects not observed at higher doses. Available with a valid prescription.
Naltrexone is an FDA-approved opioid antagonist. At low doses (0.5mg–6mg), it is prescribed off-label and has been studied for potential analgesic and anti-inflammatory effects not observed at higher doses. Available with a valid prescription.
Naltrexone is an FDA-approved opioid antagonist. At low doses (0.5mg–6mg), it is prescribed off-label and has been studied for potential analgesic and anti-inflammatory effects not observed at higher doses. Available with a valid prescription.
Naltrexone is an FDA-approved opioid antagonist. At low doses (0.5mg–6mg), it is prescribed off-label and has been studied for potential analgesic and anti-inflammatory effects not observed at higher doses. Available with a valid prescription.
Our pharmacists write about LDN research, dosing, and its off-label use across different conditions. These articles are educational, not treatment recommendations — always discuss whether LDN is appropriate for you with your prescriber.
Yes. LDN requires a valid, patient-specific prescription. We compound and dispense only upon receipt of a prescription from you or your prescriber.
No — at any dose. Naltrexone itself is FDA-approved at 50mg (opioid use disorder) and as a 380mg injection (alcohol use disorder). The low doses used for LDN (0.5–4.5mg) have no FDA-approved indication for any condition; LDN is used entirely off-label, and compounded LDN products are not evaluated by the FDA for safety or effectiveness.
Evidence varies significantly by condition. Fibromyalgia has the most clinical trial data, though results have been mixed — a 2024 trial did not confirm benefit on its primary outcome. Most other off-label uses are supported by smaller studies, case series, or case reports rather than large randomized trials. See the evidence breakdown above, and talk to your prescriber about what the research does and doesn’t show for your specific situation.
LDN cannot be taken with opioid pain medications — it blocks their effect and can trigger withdrawal. Beyond that interaction, LDN is often prescribed alongside standard treatments for the underlying condition. Always share your full medication list with your prescriber and pharmacist.
The most commonly reported effects are vivid dreams and disrupted sleep, especially in the first one to two weeks, which tend to improve as the body adjusts. Individual experiences vary — discuss what to expect with your prescriber or pharmacist.
No commercial manufacturer produces naltrexone at these low strengths — the smallest commercial tablet is 50mg. Compounding pharmacies prepare the low-dose immediate-release tablets, capsules, or liquids that off-label LDN prescribing requires.
Have your prescriber send your prescription electronically, by fax at 800.786.1405, or via our prescriber authorization form. See our prescriber page or how to order.
