Forms of Testosterone: Where Does It Come From?

As hormone replacement therapy has become more popular over the past 10-20 years, there are various assumptions being made about the treatment options and the forms they come in. There is also a multitude of questions about where testosterone in the therapy regime actually comes from.

It doesn’t make it any easier when words such as “bioidentical,” “natural,” and “synthetic” are all used across the internet. We’re here to help answer some of your questions and make things a little more clear.

forms of testosterone

Bioidentical/Natural Testosterone vs. Synthetic

The most important point to focus on is that there is a difference between bioidentical/natural and synthetic. It’s also vital to understand that all forms of testosterone are processed in a medical lab to create a source viable for human use. Theoretically, both bioidentical/natural and synthetic would be considered synthetic in the basic sense.

The difference lies within the chemical makeup of the testosterone structure as it leaves the lab for human use. The chemical structures may appear similar, but when examined closely, there are small variations that make a difference when broken down in the body. It is important to note that the majority of hormone therapy providers will use bioidentical and/or natural hormone therapies. On the flip side, general practitioners will typically work with conventional synthetic medications.

Breaking Down the Forms of Testosterone

For anyone truly interested in the science of the testosterone molecule and the difference between the bioidentical and synthetic structures, here is a basic breakdown: The testosterone molecule that is naturally produced in the human body is defined by the chemical formula C19H28O2.


When bioidentical testosterone is synthesized in a medical laboratory, it is often derived from plant sources, such as yams or soy. It is engineered to match the same exact chemical structure that is already being produced naturally by your body.

This enables it to perfectly mimic the original source. This is vital because any small variation in chemical structure from the original has the potential for side effects and hazardous changes to the functionality in which the body operates.


Synthetic testosterone medications are chemically altered to add a slight variation to the natural testosterone structure produced by our bodies. The chemical formula is altered so that the molecule may function differently within the body.

A reason pharmaceutical companies may do this is to make them more bioavailable in certain preparations (which we’ll touch on below). Another reason may be for monetary purposes–the pharmaceutical companies are able to get patents on their newly designed structures and protect them from their competition.

Finding Testosterone in the Market

There are dozens of testosterone products on the market. They can be found online, over the counter, in regular pharmacies, compounding pharmacies, etc. We see the products as gels, injections, patches,  pills, pellets, creams, and more.

Testosterone gels are the most popular type of product in terms of sales and can be applied to the arms, armpits, abdomen, and inside of the thighs. Injections are a close second when it comes to popular testosterone applications. In our practice, about 98% of our patients receive testosterone through injection. Many patients find it easier to only receive treatment 3 or 4 times a year, rather than applying a cream or gel daily.

We’ve discussed how to treat low testosterone in Part 2 of our “Testosterone for Men” video series. Be sure to check that out:

Sit Down with a Hormone Therapy Provider

Whatever forms of testosterone you’re considering, it is important to consult with your physician about your signs and symptoms. As well as the complications that can occur when considering bioidentical versus synthetic testosterone modalities.

If you’re interested in learning more about our own hormone replacement therapy program, click here. Think you might be a good candidate for low testosterone treatment? You can fill out our initial consultation form to get started and we’ll be in touch.

Before you go, be sure to check out some of our other blogs and subscribe to our YouTube channel!

Related Research