Topical vs oral finasteride
Clinically reviewed by
Oral finasteride is a major player in the world of hair loss treatments. But topical formulations of the medication are quickly capturing the attention of physicians and their patients.
In this article we cover how finasteride works, basic principles of drug metabolism and also discuss why Topical Finasteride, with SiloxysSystem™ Gel is a compounded medication that is able to support hair growth with fewer side effects.
When SiloxysSystem™ Gel was developed, it was intended to be used as a compounding medium for drugs such as finasteride. This unique delivery system can potentially minimize the risk of systemic side effects associated with finasteride and may be an option for individuals who cannot take the oral medication.
How does finasteride work?
In 1997, the FDA approved oral finasteride 1 mg daily for the treatment of male pattern hair loss (also known as androgenetic alopecia). It works by reducing dihydrotestosterone (DHT) levels at the scalp by 64% and blood levels of DHT by 68% (Cranwell & Sinclair, 2016). This reduction in DHT is thought to help delay the progression of male pattern hair loss.
When finasteride is taken as a tablet, the medicine does not reach the scalp and hair follicles instantly. It’s absorbed through the digestive system and gains access to the bloodstream. From here, finasteride travels via blood vessels to hair follicles of the scalp where it competitively attaches to binding sites on the 5-alpha reductase enzyme (5-ARIs) and blocks the conversion of testosterone to DHT.
What’s the difference between oral and topical finasteride?
The biggest difference is the potential for improved safety. Let’s start with an overview of the various ways APIs are delivered into the body.
There are several ways to deliver an API such as finasteride into the body. The oral route is popular because of its ease of administration, stability (shelf-life) and controlled dosing. However, it does have some disadvantages.
This study of how drugs are processed by the body is called pharmacokinetics. A key concept within pharmacokinetics is bioavailability, which describes how quickly and how much of a drug reaches its site of action, unchanged (Price & Patel, 2020).
How a medication is taken can affect bioavailability. In the case of the oral route, a concept known as first-pass metabolism is a consideration.
How are drugs processed by the body?
First-pass metabolism accounts for the fact that oral medications are absorbed through the intestine and subjected to processing by the liver (Le, 2020).
The acidity of the stomach and amount of mucus along the digestive tract, as well as how much time a medication spends in a particular part of the body can all affect its chemical integrity and absorption (Homayun et al., 2019).
Once a medication is successfully absorbed through the layers of the intestine, it must also pass through the liver which acts as a biological filter. Here, drugs undergo further chemical reactions that can change the structure of molecules.
These changes may affect how well the drug dissolves in liquid environments. While this can mean easier transport through the bloodstream, there is also a higher likelihood that more of the medication will be removed from the body in urine.
Researchers have determined that the bioavailability of oral finasteride is approximately 65% (Zito et al., 2021). This percentage represents the amount of API that enters the systemic circulation, unchanged.
Why is this relevant? The lower the bioavailability, the higher the dose of medication that may be needed to achieve a therapeutic effect (Price & Patel, 2021).
Additionally, when oral finasteride is absorbed and enters circulation, there is a risk that other tissues (particularly those sensitive to testosterone and DHT) become exposed to the drug and are negatively impacted.
The most commonly reported side effects associated with oral finasteride include changes to sexual function, decreased libido and gynecomastia (enlarged breast tissue) (Zito et al., 2021).
Topical formulations of finasteride may reduce side effects because they can be customized to limit the extent to which an API enters the bloodstream and concentrate the medication where it is needed the most (i.e. the scalp).
The topical route allows the API finasteride to reach hair follicles without first passing through the digestive system and liver.
What makes Topical Finasteride, with SiloxysSystem™ Gel different?
Developing a topical formulation comes with its own set of challenges and human skin is one of them. Skin has both fat and water based components and consists of several layers of specialized tissue that hold in water, maintain temperature and serve as a conduit for sensory information. XYON’s carefully designed drug delivery system takes into consideration these unique properties.
The outermost layer of the scalp is called the epidermis and it contains a layer known as the stratum corneum. This is the least permeable layer of skin and is made up of thin compressed sheets of keratin (a protein) that are tightly woven together (Yu et al., 2021).
Between these keratin sheets are layers of lipids (small fat particles) that help waterproof this layer (Weiss, 2012).
SiloxysSystem™ Gel is a water and silicone-based medium that can be mixed (with a physician’s prescription) with a medication such as finasteride. Water present in the gel causes the cells of the stratum corneum to swell, creating more space between them. This allows the API to pass more easily through this outer layer of skin and access deeper layers where hair follicles are located (Weiss, 2012).
At the same time, the gel carrier also enables the API to cross the fatty layers of the stratum corneum. This is possible as a result of loading the medication onto small carrier particles called liposomes. These liposomes are suspended throughout the gel medium.
What is a liposome?
A liposome is a specific arrangement of molecules. The molecules in question are called phospholipids. Phospholipids are unique in that one side of the molecule easily dissolves in water (hydrophilic) while the other side repels water (hydrophobic).
When placed in water, these properties cause phospholipids to spontaneously arrange into a sphere containing a central pocket of fluid.
The dual-properties of the liposome allow finasteride, a fat-based molecule, to easily integrate into the hydrophobic regions of the molecule and be transported through the fatty layers of the skin.
Liposomes also allow the API to penetrate the stratum corneum via small local blood vessels (Hagen & Baker, 2017). Eventually the API reaches the dermis, the scalp layer which lies directly underneath the epidermis. This is where it encounters target hair follicles.
One of the advantages of a liposomal delivery system when combined with our proprietary silicone gel base, is a reduction in transdermal absorption. Transdermal absorption refers to the point at which a drug passes through the dermis and enters systemic circulation.
The properties of SiloxysSystem™ Gel and XYON’s chosen concentration of finasteride allow for the controlled release of the API over time. This timed release gives hair follicles the chance to take up more of the medication, reducing excess movement of the drug into the bloodstream. This is one of the ways in which broad, anti-androgenic effects, which may be seen with the oral version of finasteride, may be minimized.
After performing clinical studies on various topical preparations of finasteride, Dr. Hasson has led the development of a highly innovative delivery system that has been shown to have both a positive effect on hair growth and good tolerability. When used as a compounding medium, SiloxysSystem™ Gel is associated with a lower risk of systemic side effects.
If you are experiencing male pattern hair loss, both oral and topical formulations of finasteride can improve the appearance and health of your hair. The biggest difference between the two is a potential reduction in side effects with the latter. A physician will need to determine which form of the medication is most appropriate in your case.
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