Calculating THC dosage of homemade edibles

Getting creative with cannabis in the kitchen can sound appealing. Who doesn't like the sound of serving canna-infused brownies fresh out of the oven? However, making edibles that deliver a safe dose of THC is a precise art, and achieving a consistent dose across every serving is a challenge. It requires meticulous math, a clear understanding of the THC content in the flower you're using, and knowledge of decarboxylation.

pot brownies edibles
Making edibles that deliver a safe dose of THC requires meticulous math, a clear understanding of the THC content in the flower you're using, and knowledge of decarboxylation. 
Photo by: Gina Coleman/Weedmaps

This is why manufacturers have to follow rigorous requirements to ensure all of their edibles contain the exact quantity of THC claimed on the package. The tools you work with at home can derail even your best attempts at accuracy. For example, if your baking tray is warped with indentations, the THC can pool, causing some servings to be very potent while others are weak. Calculating doses for homemade edibles requires care and attention.

But don't take your apron off just yet. In this article, we'll explain how to make sure your homemade edibles are dosed safely and consistently.

Why is it vital to calculate edible dosage correctly?

Edibles are distinct from other methods of cannabis delivery in several key ways. For starters, the human body processes the THC present in edibles differently. The digestive process transforms THC into 11-hydroxy-THC, which is more potent, long-lasting, and has more pronounced sedative properties. Edibles also have a delayed onset thanks to the digestive process. The high can take up to two hours to fully kick in and once it does, it can last six hours or sometimes longer. Finally, edibles can affect individuals differently. History of cannabis use, weight, age, genetics, diet, and gastrointestinal health all influence an individual's response to edibles.

An overview of edible potency

The potency of edibles is measured differently from that of flower or concentrate. In edibles, cannabinoid concentration is expressed in milligrams rather than as a percentage. THC and CBD concentrations, along with the total cannabinoid content, are typically identified on manufactured products.

Before you pull out the recipe for your favorite homemade edible, first familiarize yourself with the potency of your chosen flower. Confirm the percentage of THC, CBD, and other cannabinoids in that sampling of flower. THC potency can vary dramatically across different varieties, and flower is generally much stronger today than it was 40 years ago. If you don't know the potency of the flower you're working with, you will not be able to calculate the edible dose accurately.

Next use the flower to create a weed-infused butter or oil by gently heating it within a carrier fat. “Remember that you can't just use raw cannabis because raw cannabis doesn't contain much THC, it contains the precursor, THCA,” said Dr. Jordan Tishler, cannabis physician and instructor at Harvard School of Medicine. “To convert the THCA to THC, you have to carry out a step called decarboxylation.”

Decarboxylation of weed THCA to THC

A 2011 study published in the Journal of Molecular Structure identified the ideal conditions for optimal cannabis decarboxylation. It found that heating cannabis flower at 230 degrees Fahrenheit (110 degrees Celsius) for 110 minutes yielded the highest amount of active THC.

Heat your flower in a good-quality oil or butter, then strain, leaving the cannabinoid-infused fat or oil ready to use. The cooking time you allow for the extraction matters. Too brief and you leave behind too much unconverted THCA. Too long and you risk breaking down the THC into CBN.

Calculating the edible dosage

The recommended dose for those new to edibles is 1 to 5 milligrams of THC. That's a very small amount considering the edible itself could weigh 20 grams. For context, there are 1,000 milligrams in 1 gram. 

”Despite the fact that many recreational or self-directed users may have developed a high tolerance to THC, a high dose is neither a good thing, nor necessary for patients to get relief,” said Dr. Tishler. “Low doses are best. They can be just as helpful and avoid increasing tolerance and other side effects.  My patients typically use between 5-20 mg, with 10 mg being average.”

After you have established your desired target dose, take these steps to calculate it.

Be conservative when estimating the decarb rate

Some estimates put the total conversion efficiency between 75% and 88%, depending on the temperature and time used. But err on the side of caution and assume you will decarb 90% of the THCA into THC.

Be conservative when estimating the extraction efficiency

After you've calculated the decarb rate, calculate the extraction efficiency. Not all the THC present in the plant will infuse into the butter or oil. Assume you will extract a minimum of 60% of the THC from the plant, even if extraction efficiency is usually closer to 30%-40%. Erring on the side of caution will save you from any unwanted surprises

Do the math, then do it again

Let's suppose you start with 10 g of flower containing 20% THC. That would leave you with 2,000 mg of THC total. After decarbing the flower (2,000 x 0.9), you will have 1,800 mg of THC. Following the extraction in oil or butter (1,800 x 0.6), you will have 1,080 mg of THC in that oil, which is sufficient for 216 standard portions containing 5 mg each. 

A little cannabis goes a very long way when making edibles. As Tishler advised, “If you're making your own edibles, do the math very carefully so that you know exactly how much you're getting. You should not make the edibles stronger than necessary.” You can reduce the potency in a recipe by having a regular butter to cannabutter ratio that skews heavily in the direction of regular butter. Just make sure to adjust the math accordingly.

Ensure even mixing and portioning

Thorough mixing is absolutely critical to ensure even distribution of cannabutter or oil. “It is quite likely that you will not get uniform distribution of the medicine throughout the batch, which can lead to very different results from edible to edible,” said Tishler. With this in mind, take every precaution possible to standardize the dose across servings. 

Thorough mixing is absolutely critical to ensure even distribution of cannabutter or oil.
Photo by: Gina Coleman/Weedmaps

Here are some guidelines:

  1. If you're working with cannabutter, don't scoop from the top. Cannabinoids will settle in butter according to their weight, so when measuring out cannabutter, slice a vertical section. 
  2. When it comes to mixing, be sure to blend your batter or mix extremely thoroughly, taking care to scrape down the sides of the bowl with a spatula. 
  3. Consider using a dropper to apply an exact amount of cannabutter or oil to individual servings of non-infused food.
  4. When cutting portions, measure each piece to ensure consistency.

Effects of different CBD to THC ratios

Clinical literature suggests that CBD can counteract some of THC's less desirable effects. However, while this has been shown for inhalation methods of delivery, it has not been proven for edibles

Furthermore, CBD has a much lower oral bioavailability (5%-10%) than THC (96% or more). In addition, orally consumed THC is converted into 11-hydroxy-THC, which is significantly more potent than THC. 

CBD is therefore limited in its ability to offset THC when consumed in edible form. The presence of CBD is not a reliable way to control the potency of THC. “Many people use CBD as a way to dilute the THC to have less effect,” said Tishler. “This is expensive and not the best way to control dose. Again, it is better just to do the math correctly.”

How strong is my dose?

A diverse range of factors affect the way the body responds to cannabinoids. For this reason, dosing recommendations tend to be expressed as ranges rather than definitive quantities. Here are some guidelines:

How strong is 1mg - 5 mg?

Users with no tolerance for THC should begin with an edible containing 1 mg - 2.5 mg. This introductory quantity will be enough THC to provide a solid experience of feeling high. Users with some tolerance will likely experience feeling high from 2mg - 5 mg.

How strong is 5mg - 10 mg?

This potency is suitable for those who use cannabis several times a week. Newcomers to weed are likely to experience anxiety or even panic at this dosage.

How strong is 10mg - 20 mg?

This potency is suitable for those who regularly consume edibles and have built up a tolerance. For those who are not regular users, this dosage could lead to severe anxiety or a panic attack.

Final words of caution

If in doubt about your calculations, opt for high-quality manufactured edibles. “I recommend using commercial products for almost all my patients to avoid dosing problems,” says Tishler. Regulated dosing of manufactured edibles is one of the major benefits of legalization, second only to lab testing. 

peach ring gummy edibles
To avoid dosing problems with edibles, use commercial products to know exactly how much THC you're digesting.
Photo by: Gina Coleman/Weedmaps

Whether you are buying edibles or making them at home, start low and go slow with your dosage. Establish your tolerance baseline first before you start experimenting with higher doses. If you're making edibles for medicine, the optimal dose is the lowest amount that provides adequate therapeutic relief without adverse effects.

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The information contained in this site is provided for informational purposes only, and should not be construed as medical or legal advice. This page was last updated on July 6, 2022.