Think back to grade school, when you first experimented mixing oil and water. You'll likely recall that oil sits on the water but doesn't combine. Cannabidiol (CBD) oil has a similar reaction. CBD oil is hydrophobic, meaning it is repelled by water, and resists absorption by the body, leaving up to 90% of the cannabinoid to pass through the body unused.
Enter water-soluble CBD products. CBD is more compatible with water when it is formulated as a water-soluble product such as a nanoemulsion, liposomal product, or microemulsion. The CBD does not truly dissolve in water but water-soluble CBD is helping to unlock the cannabinoid's potential by making it more effective and versatile.
What is water-soluble CBD?
In water-soluble CBD formulations, the CBD molecules are manipulated to dissolve better in water. However, the term water-soluble is inaccurate, since CBD molecules will never fully dissolve in water, but can be transformed into a more water-compatible form.
“It isn't that the chemical composition of CBD is changing to be more soluble in water, because then it wouldn't actually be CBD anymore, but CBD can be packaged in a more easily absorbable vehicle,” explained Matthew Halpert, Ph.D. Halpert is a lecturer in the Department of Pathology and Immunology at Baylor College of Medicine, and a CBD researcher at Medterra, a manufacturer of CBD products.
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When producing water-soluble CBD, the oil particles are separated into tiny molecules by an advanced technological process. The molecules are then coated with a carrier or surfactant to stabilize them and keep them suspended in water. Smaller particle sizes allow the CBD molecules to disseminate more easily throughout water.
When CBD molecules are incorporated into water in this way, the human body is able to derive more benefits from the product. The human body is composed of up to 60% water so it makes sense that the more water soluble a product is, the easier it is for the body to transport and absorb it.
CBD bioavailability
To fully understand the benefits of water-soluble CBD, it's essential to understand the bioavailability of CBD. Bioavailability can be defined as the quantity of a substance that enters the bloodstream. CBD in its traditional oil form resists absorption into the bloodstream, which delays the onset of its impact on the user.
Another issue that limits oral CBD from reaching the bloodstream is a phenomenon called the first-pass effect. The concentration of the compound is greatly reduced before it can circulate throughout the body's system because it can't progress past the liver when ingested as an oil. This reduction in concentration also results in a decrease in bioavailability.
Reduced bioavailability affects some of the most common and convenient forms of CBD such as capsules, soft gels, tinctures, and edibles. Vaping CBD oil can yield more benefits because the molecules are transported by vapor particles and are therefore more easily absorbed by the lungs.
How is water-soluble CBD made?
Ultrasound is used to create vacuum bubbles in the CBD molecules, which causes them to implode, hit surrounding bubbles, and break into smaller droplets. Water-soluble CBD is generally either prepared as a liposome, nanoemulsion, or a microemulsion.
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Liposome: Liposomes are a potent way of delivering nutrients to the body. With liposomal CBD, the CBD molecule is surrounded by or attached to a fat.
Once the liposome reaches its destination and fuses with the cell, it releases the CBD. Liposomal CBD droplets measure between 100 and 5,000 nanometers.
Nanoemulsion: Nanoemulsions atomize CBD molecules even further, making them easier for the body to absorb. Smaller drops create a larger surface area to interact with the body's tissues and enzymes.
The average size of a droplet of nano-emulsified CBD is 25 nanometers. Nanoemulsions are usually mixed with penetration enhancers to help spread the CBD further. They can be taken either orally or topically, with uptake occurring almost immediately after administration. This should result in higher potency and faster onset of action for lower doses.
Microemulsion: CBD microemulsions are also available but are less common. Microemulsion droplets measure between 100 and 5,000 nanometers, which means they can penetrate a larger surface area, but they require the use of surfactants to dilute the compound.
Microemulsions require ten times as many surfactants as nanoemulsions. A surfactant is a substance that helps to reduce the surface tension of CBD oil, increasing its ability to spread and disperse. Less is more when it comes to surfactants in products which will be ingested, which is why nanoemulsions are more popular.
All of these formulations increase the bioavailability of CBD so it can be better absorbed by the body.
The science behind water-soluble CBD
Both liposomes and nanoemulsions have been well-researched with a range of compounds.
“There are decades worth of scientific research that provide evidence of liposomes increasing the bioavailability of molecules not easily taken in by the body,” Halpert said.
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However, research on liposomal CBD and CBD nanoemulsions is still in the early stages. There are a few published studies which suggest promising results.
A 2018 review published in “Molecules” found that the lipophilic nature of CBD rendered it a good candidate for nanotechnology drug delivery strategies.
A 2019 pre-clinical study investigated the efficacy of a CBD nanoemulsion in rats. The researchers found the nanoemulsion improved bioavailability by about 65%, and accelerated the onset of action of the CBD.
A 2018 study published in the Journal of Pharmaceutical Sciences investigated the bioavailability of Sativex oromucosal spray compared with a CBD/THC nanoformulation in 14 healthy male volunteers. On the days that the volunteers received the nanoformulation, they experienced faster absorption and improved bioavailability of the product.
Does CBD oil have to be water-soluble?
CBD can still offer benefits when administered as an oil. For those who prefer their supplements in a more familiar form, CBD oil will likely eternally hold appeal, although it doesn't have the bioavailability of water-soluble CBD. It is likely, however, that the trend will continue towards more CBD products that utilize the nano-emulsification process.
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Halpert does stress, however, that not all water-soluble CBD is necessarily better. It can actually be worse if made using poor production techniques.
How long does water-soluble CBD stay in your system?
The absorption rate, the degradation rate of the CBD, and the receptivity of the individual to the product will all contribute to the length of time results are felt.
“The jury is still out on how long water-soluble CBD can remain in the body,” Halpert said.
Although there is no hard and fast answer, it is worth noting that high-quality, third-party tested, water soluble CBD boasts quicker onset and greater efficacy. Water soluble also requires a smaller dose due to its enhanced bioavailability, meaning the same size bottle of CBD should last longer.
How can water-soluble CBD be taken?
Water-soluble CBD is highly versatile and is often sold in liquid or powder form. It's also available in oral, topical, and nasal spray forms. Nanoemulsified CBD is translucent, meaning it is visually undetectable when stirred into beverages. It can also be incorporated into food, allowing it to be widely used in everyday life.
Water-soluble CBD is also particularly useful when applied as a topical formula. While oily CBD creams sit on the skin, water-based serums can more effectively soak in by penetrating the spaces between cells.
How is water-soluble CBD isolate made?
CBD isolate is created when CBD molecules are subjected to a more complex process of extraction than full-spectrum CBD oil. The end result is CBD isolated into a crystalline form, without additional cannabinoids or terpenes.
Even CBD isolate, a highly purified form of CBD, is still hydrophobic. Nanotechnology is needed for CBD isolate to become more compatible with water.
“Water-soluble CBD isolate is the exact same CBD isolate as before, but it just goes through this extra process of packaging on the nano-scale,” Halpert said.