How Does CBD Oil Affect Vitamin and Supplement Intake?

From its beginnings as an alternative medication for pain, anxiety, and sleeping disorders, CBD has undoubtedly outgrown the stigma from its association with cannabis. Just like Vitamin C, many are now considering it as an indispensable supplement for improving overall health. So, will taking CBD oil affect vitamin and supplement absorption?

Because consumers are increasingly recognizing CBD as an “all-natural” panacea that can do no harm as opposed to most prescription drugs, it makes perfect sense for companies to treat it like a regular vitamin or supplement and market it as such.1 In fact, CBD multivitamins are now commonplace in most supplement shops and even come in various ways of delivery, from the standard capsule form to the innocuous chewable “gummies”. 

However, studies still have a lot to uncover about CBD. Most consumers are still wondering if CBD oil affect vitamin and supplement metabolism. Are there any harmful side effects to taking CBD with certain vitamins, or if there are none, would CBD reduce the effect certain vitamins and vice versa? This is a possibility since it has been scientifically established that there are certain vitamins or minerals which should not be taken together. For example, calcium is known to inhibit the absorption of iron2 which is why it is advised that the two be taken at different times during the day, especially for pregnant women who need more of both.

Since CBD can be quite expensive, it would not be economical to have its effects reduced. Likewise, it would not be ideal to have it reduce the effects of other supplements. To achieve maximum effect, it is important to know which supplements can be taken with CBD at the right dose with the right food.

Taking CBD with vitamins or supplements

Existing research and anecdotal evidence both suggest that it is safe to take CBD with the most common vitamins and supplements in the market. However, it may interfere with the absorption of some, particularly those metabolized by the liver. 

As mentioned in another article, Drugs to Avoid While Using CBD?, CBD is known to inhibit the activities of the cytochrome P450 system which is a set of liver enzymes responsible for metabolizing compounds commonly found in prescription medication. Therefore, CBD can interfere with the absorption of any supplement that is metabolized by the CYP450 system. 

It should be noted that CBD is not the only natural supplement that can inhibit the CYP450 system. Some others include grapefruit3, watercress4, St. John wort5, and goldenseal.6

Delivery format affects CBD absorption and interaction

The delivery method is a major factor that affects CBD absorption. It also determines the impact of CBD on the absorption of other supplements. 

Each delivery method has its own advantages and disadvantages, despite some allowing faster and better absorption than others. Because of this, consumers can now choose from a wide variety of CBD products at different price points, depending on what condition they are treating or how they want to use CBD. Here are the general classifications of CBD delivery methods:

  • Injectables – Injecting pure cannabidiol into the bloodstream results in the highest bioavailability of all delivery formats. CBD injections are very uncommon and only typically done only at medical facilities. 
  • Inhalation – This can be any method of taking CBD via the respiratory system. This includes smoking cannabis, vaping CBD e-juices and isolates, nasal sprays and CBD inhalers. This offers the highest bioavailability next to injectable CBD.
  • Sublingual/Oral – These are usually capsules, tablets, oils or sprays that allow CBD to be absorbed under the tongue or mouth tissue. Sublingual CBD only comes second to vaporized CBD in terms of bioavailability.
  • Suppositories – These are capsule-shaped pills that melt under body temperature and are designed for anal or vaginal insertion. Suppositories make CBD more bioavailable compared to edibles.
  • Edibles – These can be liquids or food that allows CBD to be carried and absorbed through the digestive system. Although popular and convenient, bioavailability is significantly less with edibles7 since digestive acids and enzymes can destroy CBD before it can get absorbed by the intestinal wall and the amount that gets absorbed will still be metabolized by the liver before it reaches the bloodstream. 
  • Topicals – This can include products like balms, creams, massage oils or shampoos that allow CBD to be absorbed through the skin. Topicals have the least bioavailability of all methods but are more effective in treating skin conditions and localized pain.

CBD and the first-pass effect

Of these delivery methods, edibles are the only ones subject to the first-pass effect8 which roughly means that the concentration of CBD gets considerably reduced since it still has to be processed by the liver. In addition to this, CBD is also water-insoluble, so this results in a relatively low bioavailability of only around 4-20%.9. However, edibles with enhanced bioavailability, such as water-soluble CBD and nano emulsified CBD are now making its way into the market.

Knowing the bioavailability of edibles should be helpful when considering products like CBD multivitamin capsules. 

Interaction of CBD and Common Supplements

There have been no reported cases of CBD causing any harmful side effects when taken with common supplements. It also does not have any known interaction with the following vitamins and minerals:

  • Vitamin A
  • Vitamin B6; B12
  • Vitamin C
  • Calcium
  • Echinacea
  • Ginseng
  • Fish oil, krill oil (Omega-3)

At least one study10 shows that taking CBD with iron supplements has a positive effect. In this study, researchers found that CBD can potentially counter the effects of iron accumulation linked to neurodegenerative diseases such as Alzheimer’s.

The lack of research makes it difficult to confirm if CBD has interactions with lesser-known vitamins, minerals, and supplements. This is not stopping manufacturers from mixing it with multivitamins and other popular supplements such as acai berry, green tea, turmeric, among others. 

Which supplements should you not take with CBD?

Given CBD’s effect on the liver’s cytochrome P450 enzymes, it is safe to say that supplements that metabolize or inhibit this system should not be taken with CBD, or at least taken at a different time of the day. 

Vitamin D11 is one such supplement that uses CYP450 for bioactivation, while components of ginkgo biloba12 will inhibit it. Likewise, St. John’s wort13, a popular herbal remedy for depression, can both induce and inhibit the activities of CYP450 so these supplements are best not taken with CBD.


Because it is confirmed that CBD oil affect vitamin and supplement absorption, it’s better to take it separately instead of ingesting it as a part of an oral supplement. It is also better to take CBD as sublingual drops or tablets to avoid the risks associated with vaping. By choosing a delivery method for CBD that bypasses the liver, the upside of taking it with vitamins and minerals, with the exception of those that have an effect on CYP450 enzymes, is greater than its possible adverse effects.  

  1. Angelica LaVito. Vitamin Shoppe to sell edible CBD supplements as consumers clamor for cannabis compound[CNBC]
  2. National Institutes for Health. ”Calcium”[NIH]
  3. Wikipedia contributors. ”Grapefruit–drug interactions”[Wikipedia]
  4. Lester Packer, Sissi Wachtel-Galor, Choon Nam Ong, Barry Halliwell. Herbal and Traditional Medicine: Biomolecular and Clinical Aspects[Google Books]
  5. Komoroski BJ1, Zhang S, Cai H, Hutzler JM, Frye R, Tracy TS, Strom SC, Lehmann T, Ang CY, Cui YY, Venkataramanan R. Induction and inhibition of cytochromes P450 by the St. John’s wort constituent hyperforin in human hepatocyte cultures.[PubMed]
  6. Chatterjee P1, Franklin MR. Human cytochrome p450 inhibition and metabolic-intermediate complex formation by goldenseal extract and its methylenedioxyphenyl components.[PubMed]
  7. Tracey Roizman. CBD Bioavailability: What Does it Mean Why is it so Important?[Daily CBD]
  8. Lester Sultatos. First-Pass Effect[ScienceDirect]
  9. Hempure. What is First-pass Metabolism?[Hempure]
  10. Vanessa Kappel da Silva,1,2 Betânia Souza de Freitas,1 Rebeca Carvalho Lacerda Garcia,1 Ricardo Tavares Monteiro,1 Jaime Eduardo Hallak,2,3 Antônio Waldo Zuardi,2,3 José Alexandre S. Crippa,2,3 and Nadja Schrödercorresponding author2,4 Antiapoptotic effects of cannabidiol in an experimental model of cognitive decline induced by brain iron overload[PMC]
  11. Wikvall K1. Cytochrome P450 enzymes in the bioactivation of vitamin D to its hormonal form (review).[PubMed]
  12. von Moltke LL1, Weemhoff JL, Bedir E, Khan IA, Harmatz JS, Goldman P, Greenblatt DJ. Inhibition of human cytochromes P450 by components of Ginkgo biloba.[PubMed]
  13. Komoroski BJ1, Zhang S, Cai H, Hutzler JM, Frye R, Tracy TS, Strom SC, Lehmann T, Ang CY, Cui YY, Venkataramanan R. Induction and inhibition of cytochromes P450 by the St. John’s wort constituent hyperforin in human hepatocyte cultures.[PubMed]

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