Low dose naltrexone (LDN) requires a prescription and is almost exclusively available through compounding pharmacies. You cannot buy it over the counter or pick it up as a standard prescription at a chain drugstore. The typical out-of-pocket cost runs under $100 per month, and most people get started by asking their doctor for a prescription specifying a compounded dose.
Why You Can’t Buy It at a Regular Pharmacy
Naltrexone is FDA-approved only at 50 mg for treating alcohol and opioid use disorders. That’s the version stocked at standard pharmacies. Low dose naltrexone uses between 0.5 mg and 4.5 mg, which is roughly one-tenth to one-hundredth of the commercial tablet. No manufacturer sells naltrexone in these small doses as a ready-made product.
This means a compounding pharmacy has to custom-prepare your prescription. Compounding pharmacies take bulk ingredients and create medications in specific strengths and forms that aren’t commercially available. For LDN, they typically make capsules or liquid formulations tailored to whatever dose your prescriber orders. Capsules commonly come in strengths like 0.5 mg, 1.5 mg, 3 mg, or 4.5 mg. Liquid versions allow finer dose adjustments, which matters because many prescribers start at a very low dose (sometimes 0.1 mg) and gradually increase.
Getting the Prescription
Any licensed prescriber can write a prescription for LDN. There’s no special certification or waiver required, unlike some other controlled substance treatments. Your primary care doctor, a pain specialist, a rheumatologist, or a nurse practitioner can all prescribe it. The practical challenge is that not every provider is familiar with off-label low dose use, so you may need to bring it up directly or seek out a provider who has experience with it.
Your prescription will specify the exact dose, the form (capsule or liquid), and the quantity. Some prescribers write for a starting dose with instructions to titrate up over weeks, while others prescribe a fixed dose like 4.5 mg from the start. Research suggests effective doses for chronic pain range from 1.0 mg to 4.5 mg per day, though one observational study found that many patients did well at 2 mg or less. The titration approach, starting very low and increasing gradually, helps identify the dose that works best for you while minimizing side effects.
Finding a Compounding Pharmacy
You have two main options: a local compounding pharmacy or an online compounding pharmacy that ships to your state.
For local pharmacies, search for “compounding pharmacy” in your area and call to confirm they prepare LDN. Not all compounding pharmacies make every medication, so it’s worth checking before you send your prescription over. The LDN Research Trust maintains an online directory of pharmacies that have self-reported they compound LDN, though the organization notes it does not independently verify the listings. It’s a starting point, not a guarantee of quality.
When choosing a pharmacy, look for PCAB accreditation. The Pharmacy Compounding Accreditation Board, administered through the Accreditation Commission for Health Care, is considered the gold standard for compounding pharmacies. PCAB-accredited pharmacies undergo rigorous assessment for quality and safety standards. This matters because compounded medications don’t go through the same manufacturing oversight as commercial drugs, so accreditation is your best proxy for consistency and purity.
Online Compounding Pharmacies
Several legitimate online compounding pharmacies ship LDN directly to your door. These still require a valid prescription from your provider. Some telehealth services have streamlined this process by pairing a virtual consultation with a partnered compounding pharmacy, so the prescription and fulfillment happen in one workflow.
Stick to pharmacies that are licensed in your state, require a prescription, list a physical U.S. address and phone number, and have a licensed pharmacist available for questions. The FDA has issued warning letters to online pharmacies that sell prescription drugs without requiring prescriptions, offer products of unknown origin, or skip required safety information. Purchasing naltrexone from overseas or no-prescription websites carries real risks: you may receive the wrong dose, contaminated products, or nothing at all.
Cost and Insurance Coverage
Compounded LDN generally costs less than $100 per month out of pocket. Some pharmacies price it well below that, with daily costs sometimes under a dollar. The raw ingredient is inexpensive; most of what you pay covers the compounding labor and quality testing.
Insurance rarely covers compounded LDN. Because the low dose formulation is not FDA-approved for any specific condition, insurers typically classify it as off-label and exclude it from formulary coverage. The silver lining is that the cash price is low enough that most people can manage it without insurance. Some pharmacies offer multi-month supplies at a discount, so it’s worth asking.
Capsules vs. Liquid
Compounding pharmacies can prepare LDN in several forms: capsules, oral liquid, sublingual drops, and occasionally topical creams. Capsules are the most common and convenient for people on a stable dose. They come in fixed strengths, so if your prescriber wants you on 3 mg, you take one 3 mg capsule daily.
Liquid formulations are more flexible. A typical preparation might be 1 mg per milliliter in a 30 mL bottle, allowing you to measure precise doses with a syringe. This is especially useful during the titration phase when your dose changes frequently. Some people start on liquid and switch to capsules once they find their optimal dose. Others prefer liquid long-term because they dislike swallowing capsules or need a dose that doesn’t come in a standard capsule size.
Compounded LDN capsules are typically stable for at least six months, and one stability study found 1.5 mg capsules remained potent for a full year. Your pharmacy will print a beyond-use date on the label. If you’re ordering a larger supply, capsules generally have a longer shelf life than liquid preparations.
What to Avoid
Some people attempt to make their own LDN by cutting or dissolving commercial 50 mg tablets. This is unreliable. Splitting a 50 mg tablet into precise 1.5 mg or 4.5 mg portions is nearly impossible to do accurately, and the active ingredient may not be evenly distributed throughout the tablet. Dissolving a tablet in water and measuring out a fraction can get closer, but introduces variables around stability, absorption, and dosing precision that a compounding pharmacy controls for.
Websites selling “naltrexone” without a prescription, particularly from overseas, should be avoided entirely. These products may contain incorrect doses, wrong ingredients, or contaminants. A legitimate compounding pharmacy with proper licensing is the only reliable source for accurately dosed LDN.