This page describes the steps to take to prepare a solution containing one milligram  of nalrexone per milliliter.

Since there is no recognized use of naltrexone for off-label applications, there are also no officially recognized doses for any off-label conditions. The instructions below assume you will prepare a dilution of naltrexone in a consistent manner and take a consistent ml dose regardless of small measurement errors by using common household utensils.

Accuracy of “Drug Substance” Contained in Capsules and Tablets

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Naltrexone Tablets 50 mg

The United States Pharmacopeia is a compendium of information about drugs that establishes quality standards.  It refers to the active ingredients of a medication as the “drug substance.” Capsules and tablets containing the drug substance are required to adhere to standards of purity and quantity. The margin of error for the amount of drug substance in each tablet is very small. A tablet of naltrexone, whether generic or brand name, contains 50 milligrams of naltrexone plus or minus a very small amount. Everything you do to prepare the low dose used for Low Dose Naltrexone (LDN) purposes will introduce small and inconsequential errors in the final amount contained in one milliliter of distilled water.

Accuracy is not Critical

The dose of naltrexone you take to treat off-label conditions is determined empirically. Usual doses taken for autoimmune disorders and cancer range from 1 mg. to 10 mg.  The most common published average dose is 4.5 mg, which means very little because arriving at the 4.5 mg dose is based on symptoms and most people cannot tell the difference between symptoms at 4 mg or 5 mg, although many can tell when a smaller dose works better than a larger dose, e.g. 2 mg vs. 4.5 mg.

We are not recommending any doses here; we are just describing how to prepare a solution containing close to 1 mg. per ml.  As long as you use the same measuring paraphernalia, your dilution will remain essentially the same over the extended time that you take it. Most people find a dose that works and stay there.

Measuring Utensils

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Erlenmeyer Flask

Unless you purchase a calibrated graduated cylinder, the volume of distilled water you measure will be off by a few tenths of a ml.  A measuring cup we purchased at Walmart for around $2.00 compared favorably with a calibrated cylinder, but a small Erlenmeyer flask (pictured) containing 50 ml. turned out to be off by about 10%.  The flask is made in China and is clearly marked “approx.” under the 50 ml. mark.

The pediatric oral dose syringe that we got from the pharmacist at no cost is accurate within our ability to compare it to the graduated cylinder.

Dilution versus Compounding Pharmacist

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Oral Syringe with Fill Cap

Not very many doctors prescribe low dose naltrexone. Of those who do, many write a prescription for a compounding pharmacist to prepare the prescribed dose. While there are a few on-line pharmacies who prepare low dose capsules at a reasonable price, most compounding pharmacies do not have the economy of scale to prepare the prescription at a low price.

If your doctor will listen to you, ask for 50 mg tablets, which cost around $30 for 30 tablets.  Because the standard dose for naltrexone is 50 mg daily by mouth, the instructions on the prescription may read, ” take one tablet by mouth once daily (titrate as directed)”  Sometimes the pharmacists express concern because they want to give you instructions about taking a new prescription and the part about titrating throws them off unless they have previous experience with LDN.

There are websites that have good information about how to obtain a prescription if your own doctors are hesitant. is one such site.

A single 50 mg tablet costing about one dollar will last 11 days when a person is taking 4.5 mg daily.  In practice the last dose may have a lot of the excipient in it and there is no great loss in discarding it.

Measure 50 ml of Distilled Water

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Break 50 mg Tablet in Half in Small Container

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Add 50 ml. of Distilled Water

The tablet dissolves very quickly.  The excipients in the tablet do not dissolve and will make the solution cloudy when shaken.

Place the lid on the container and put in the refrigerator for storage. Naltrexone is stable at both room temperature and refrigeration temperatures for at at least 60 days and not significantly affected for 90 days when stored at 39 degrees and 77 degrees Fahrenheit. An advantage of storing in the refrigerator is that it is dark and protected from any possible effects of light or elevated temperatures if inadvertently placed in sunlight.

Shaking the solution to suspend the excipients or allowing them to settle and then drawing up the dose in the syringe or calibrated dropper makes no difference in the dose. Naltrexone is very soluble in water.


image of soft drink

Cola Drink

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Filling the Oral Syringe

Draw the appropriate dose into the oral syringe. Start with a low dose and work up to a dose that has no side effects and yields an improvement in symptoms.  Squirt it in your mouth and chase it down with something like a soft drink to kill the bitter taste. LDN is typically taken at bedtime.

There are no recognized doses for specific health problems.  It has been widely reported that more is not better. Sometimes a higher dose results in worsening symptoms, which improve when the dose is reduced.

It has also been reported that taking a dose holiday results in renewed efficacy when dosing is resumed.

Other Paraphernalia

You need to use a wide mouth container when using the small oral syringe to measure the dose. The one pictured above has a lid that is harder to remove that other types of jars like the ones pictured below.  Small jelly jars are also useful.

The glass stoppered Erlenmeyer flask and any narrow mouth bottle are also very convenient but they require a long calibrated dropper to draw the solution out.

10 ml syringe for larger doses