What is bioavailability: why better absorption matters

Bioavailability helps us understand how well a substance is absorbed and utilized by the body. Below is a closer look at why this matters.

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If you take medicine, vitamins, or supplements you are likely familiar with dosage forms and recommendations for the given substance. Your daily vitamins will typically list the different vitamins and minerals and their corresponding amounts.

While being aware of this information is important, it is also to understand the context of these amounts as your body will likely not utilize 100% of the amount listed in a single dose.

The body's inability to utilize 100% of a given substance has to do with a number of different variables. Understanding the amount your body can absorb and utilize is important to ensure your body is getting the correct dosage. This is where the concept of bioavailability comes in.

Below is a closer look at bioavailability, how it is determined, why it is important, and why you should look for better bioavailability in your supplements.

What is bioavailability?

Bioavailability may sound like just another scientific buzzword, but the reality is that bioavailability is an important concept that plays a role in the dosage of medicine, supplements, and vitamins.

Bioavailability refers to the ability of a substance to be absorbed and utilized by the body. In essence, bioavailability is a measure of how effective a specific substance is in delivering your body the micronutrients it needs.

How is bioavailability determined?

Bioavailability is an important measurement for dosing substances correctly, but how exactly is it determined? The answer is actually much easier than one might think. Typically, the process involves blood testing for the target substance following the administration.

Utilizing a supplement as an example, a predetermined dose is given orally in the form of a tablet or capsule. Following the administration, blood samples are taken over time and the plasma concentration found in the blood is calculated.

Knowing how much of a substance you took in and the relative amount that was successfully able to enter your bloodstream allows you to calculate the bioavailability percentage.

How is bioavailability used?

In medicinal product formulation, the bioavailability of medicines plays an important role in determining the appropriate therapeutic dosage. If a substance is readily absorbed through digestion and quickly enters your systemic circulation it will likely require a lower dosage than a substance that has a hard time being digested.

This is mainly applicable to oral medications. If medicinal administration occurs intravenously, then the relative bioavailability of that medication is much higher, usually close to 100%.

Understanding the bioavailability of a medicinal product is vital in ensuring the active ingredient has a safe administered dose to avoid ineffectiveness or toxicity.

This same concept is utilized when determining the proper dosage for vitamins and supplements.

Certain supplements may only require a small dose to meet your dietary requirements while others may have an amount that is well over what is recommended for you to have in a day due to low bioavailability. This is oftentimes why you will see some vitamin supplements with over 100% of your recommended daily allowance as most of it will likely pass through without getting into your body.

Additionally, many vitamins such as vitamin C and vitamin B are water-soluble, which means that they dissolve easily in water. This in turn means that no matter how much you increase your intake of one of these vitamins, your body will only use as much as it needs and flush the remaining excess throughout the day.

How bioavailability can be increased?

Bioavailability is an important factor to analyze to produce more effective medicinal products and supplements. Why waste when you can aim for substances that are more tailored to your body and more readily absorbed? Below is a closer look at some of the techniques utilized to increase the uptake of substances within the body.

Biochemical design

Some molecules have poor bioavailability due to inherent characteristics of the molecule. A prime example of this is CoQ10. CoQ10 is a relatively large and lipophilic molecule that results in it not being a well-suited molecule to properly be absorbed by the body in supplement form.

These limitations in chemical composition have led many CoQ10 supplements manufacturers to simply increase the dose to try and offset the loss associated with low bioavailability — that is until MitoQ entered the market.

MitoQ is a modified form of CoQ10 that is shorter and contains a positive charge. These changes might seem small, but they resulted in a large increase in bioavailability as the molecule is more suited to pass through cellular membranes and incorporate itself into the mitochondria.


Increasing absolute bioavailability of medicines and vitamins doesn't always have to be done in the lab, as is the case with fat-soluble vitamins.

Vitamins A, E, D, and K, as well as minerals like calcium, make up the main fat-soluble vitamins needed in your diet. These vitamins can have a difficult time being absorbed when taken alone as a supplement.

When taken with a meal with fat, however, their absorption through digestion tends to increase.

Route of administraiton

One of the largest factors that can impact the bioavailability of a molecule is the digestive tract. The digestive system is well adapted to getting nutrients out of food and breaking down more complex molecules into more usable forms for the body, but this same system poses a large problem with the ingestion of medications, vitamins, and supplements.

The digestive system contains a number of different enzymes and chemical conditions to help it break down food. This includes digestive enzymes like pepsin and the highly acidic environment of the stomach.

Molecules that utilize an oral route of administration must be able to go through these harsh environments and reach the intestines to be absorbed into the bloodstream. Unfortunately, the hepatic first-pass metabolism can significantly inhibit bioavailability of important active ingredients.

Rather than working to improve the absorption in the gastrointestinal system to improve bioavailability, a different route of administration can be taken.

An intravenous (IV) route of administration for example completely forgoes digestion and gets the molecule directly into your bloodstream. Ringer's lactate is a prime example of a solution is administered via IV to ensure high bioavailability and immediate use for cases of severe dehydration.

Why bioavailability matters

Bioavailability undoubtedly has its purpose in the design and dosage of medications , supplements, and vitamins but how exactly is bioavailability important to a consumer? Below is a closer look at why bioavailability matters and why you should look for higher bioavailable products when available.

Money down the drain

Some supplements are better than others in terms of their bioavailability and as such manufacturers tend to opt for higher dosages when bioavailability falls short. While many people see more as better, in terms of bioavailability this isn’t the case. Getting more of a less bioavailable molecule means that more of it is going to end up eliminated through urine or stool.

Getting more bioavailable products on the other hand means that less of it is going to waste and that your body is actually able to utilize it. As is the case with MitoQ versus other CoQ10 supplements. Because of the increased bioavailability of MitoQ, it is offered in a smaller dose while still offering the mitochondrial support your cells need.


Bioavailability also plays a role in the efficacy of a product. The easier it is for a molecule to be absorbed and integrated where it needs to be, the more effective it will be at providing its intended results.

Creating more effective supplements, vitamins, and drugs typically has something to do with improving the bioavailability of the molecule. Whether that be improving the digestibility or improving the transport of the molecule to target tissues or organelles, pharmacology professionals want to deliver the most effective medicinal therapy possible.

As an added bonus, better bioavailability can help mitigate the side effects of certain supplements and medicines. Because many people take more than the suggested amount of medicines and supplements to offset decreased bioavailability, they can experience negative side effects like stomach upset that occur due to overconsumption of filler materials.

When a medicine has higher bioavailability, the chances of these unintended side effects occurring are significantly reduced. Toxicology experts often monitor blood serum and dietary proteins along with bioavailability to make sure that medicines and supplements have a lower chance of these side effects as well.

Bioavailability and cellular health

Cellular health is an emerging focus of health and wellness that takes a closer look at your health from a micro perspective. Rather than taking a top-down approach to health, cellular health utilizes a bottom-up approach that focuses on supporting your body at the microscopic cellular level to improve your overall well-being.

Bioavailability and pharmacokinetics play a large role in cellular health. Supporting your cells involves providing all of the nutrients, molecules, and vitamins it needs to function at their peak performance. Getting these molecules to the cells is not an easy task and having a higher bioavailability certainly helps.


In summary, bioavailability is a measure of how effectively your body is able to utilize a particular substance. For medicines , this plays an important role in providing a therapeutic dose. For supplements and vitamins, bioavailability ensures that you are getting enough of the molecules your body needs to support your overall health.

One of the most crucial components of your cellular health is optimal mitochondrial health. The mitochondria are the powerhouse of the cell and they convert glucose and oxygen into a usable form of energy known as ATP. The mitochondria are constantly pumping out ATP to meet the energy demands of the cells. This process however can slow down as a result of CoQ10 deficiency.

Traditional CoQ10 supplementation may be able to help restore levels in the mitochondria but the molecule has a hard time getting through the selectively permeable mitochondrial membrane.

MitoQ on the other hand is able to readily cross the mitochondrial membrane and provide antioxidant support to where it matters. In this way, bioavailability truly makes a difference.

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