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Finasteride vs. ProCelinyl™: A Story of Side Effects

Finasteride vs. ProCelinyl™: A Story of Side Effects

If you’re investigating hair loss solutions, you’ve likely heard of the old standbys: minoxidil, commonly branded as Rogaine, and finasteride, the generic name for Propecia. We’ve taken a look at minoxidil before, but today, let’s get into the basics of finasteride for hair loss and how the prescription medication stacks up to ProCelinyl™, a breakthrough ingredient that is fundamentally changing the hair loss industry.

This post may get a bit technical, so let’s break down some key definitions first to make sure we stay on the same page throughout the length of the post!

What terminology should I know?

Before we get too far into the weeds, let’s revisit some of the relevant vocabulary:

  • Testosterone: The major androgen, or male sex hormone.
  • Dihydrotestosterone (DHT): A metabolized version of testosterone, DHT is more potent at binding to androgen receptors than testosterone.
  • 5α-reductase: The enzyme responsible for converting testosterone to DHT.
  • Androgen receptor: A structure that binds an androgen—like testosterone or DHT—and generates a response, usually by regulating the expression of genes related to male sexual traits.
  • Agonist: A chemical that interacts with a receptor to activate it and generate a response.
  • Antagonist: A chemical that interacts with a receptor to bind and block an agonist from binding to it and generating a response.
  • Inhibitor: A chemical that disrupts a biological function, such as disrupting the metabolism of testosterone into DHT by interfering with the activity of 5α-reductase.


What is finasteride?

Finasteride is a prescription drug used to treat two separate, but related, conditions in men: 

  1. Benign prostatic hyperplasia (BPH), or an enlarged—but non-cancerous— prostate.
  2. Androgenetic alopecia (AGA), or male pattern baldness.
Pill in man's hand

Alongside minoxidil, finasteride is one of the two FDA-approved treatments for hair loss. While finasteride is the generic name for the compound, it’s commonly marketed under the trade names Proscar and Propecia for the treatment of BPH and AGA, respectively.

As a drug, finasteride falls within the class of drugs known as 5α-Reductase inhibitors (5-ARIs), which work by inhibiting one or more of the three forms of the enzyme 5α-reductase. Inhibiting 5α-reductase disrupts its ability to convert the androgen testosterone into dihydrotestosterone (DHT), the potent androgen that causes follicle miniaturization and hair loss. For this reason, 5-ARIs are also commonly known as DHT blockers.

When used to treat androgenetic alopecia, finasteride is taken orally in tablet form at a dose of 1mg once daily. For the treatment of BPH, the dose is 5mg once daily.

How does finasteride work?

We’ve gotten the basic vocabulary out of the way, so let’s discuss how finasteride works. As we mentioned earlier, finasteride achieves its effects by inhibiting the activity of types 2 and 3 of the enzyme 5α-reductase. Because 5α-reductase converts testosterone into DHT, and because DHT causes hair follicles to miniaturize and thin the hair strands they produce, inhibiting the activity of 5α-reductase means that less DHT ends up being produced. Less DHT means less follicular miniaturization, and less miniaturization means less hair loss. When using finasteride daily, early results can be seen in 3-4 months, but because of the nature of the hair growth cycle and the length of hair you’re trying to replace, full results may be seen near the one year mark.

Schematic of DHT effects on body

Because it works on male sex hormones, finasteride isn’t approved for use in women. Some studies have begun to investigate the use of antiandrogens in treating female pattern hair loss, but the results and side effects remain mixed.

Schematic of finasteride mechanism

How was finasteride developed?

The path to the development of finasteride took several decades and chance discoveries.

In 1942, James B. Hamilton of the Yale University School of Medicine published his findings that correlated male pattern hair loss with male sex hormones. By examining men who had failed to reach sexual maturity due to castration at a pre-pubescent age, Hamilton found that none of them suffered from the typical signs of male pattern baldness and hair loss. In men who were castrated during their adolescent years, most retained a full head of hair, while some had slight hair loss.

The next step wouldn’t come for the next three decades. In 1974, Julianne Imperato-McGinley of Cornell Medical College in New York presented her results documenting the traits of a group of intersex children in the Dominican Republic who presented as female at birth, but began to develop male traits and genitalia at the age of 12. Known as guevedoces, Imperato-McGinley found that the children shared a rare genetic mutation that impaired the expression of the 5α-reductase enzyme. Given that 5α-reductase converts testosterone to the potent androgen DHT, it was posited that the absence of DHT contributed to the delayed development of male sexual traits. As one of her observations made in the presentation, Imperato-McGinley noticed that among the guevedoces, the prostate remained small.

In 1975, Roy Vagelos—then the chief of basic research at pharmaceutical giant Merck—seized on that line. Looking for a potential non-surgical treatment for an enlarged prostate, Vagelos found a pathway that, if targeted, could possibly lead to a reduction in prostate size in adult men suffering from the condition. Millions of men suffered from an enlarged prostate—more than 70% of men are impacted by age 65—and it stood as a clear example of a painful, embarrassing condition where seeking treatment could often be a struggle.

By 1992, the FDA granted approval to Merck’s finasteride—branded as Proscar—for the treatment of BPH at 5mg taken once daily. As a side effect, Merck discovered that men receiving Proscar for BPH were growing hair. Given the paucity of treatment options for hair loss, Merck identified a new indication for its existing drug: By 1997, Merck received FDA approval for a 1mg dose of finasteride—branded as Propecia—for the treatment of hair loss caused by androgenetic alopecia in men. Again, we’d like to emphasize that finasteride is only FDA-approved for the treatment of hair loss caused by androgenetic alopecia in men. Women aren’t able to take advantage of finasteride—or any other FDA-approved medication—to address this specific indication and treat their pattern hair loss issues.

Are there any comparable drugs to finasteride?

Yes, there are a handful of other compounds and drugs within the class of 5-ARIs, though none of them have received FDA approval for the treatment of androgenetic alopecia.

Dutasteride—marketed under the trade name Avodart for the treatment of BPH—is more effective at targeting all 3 types of 5α-reductase and has been shown to suppress DHT more effectively as a result. In contrast, finasteride selectively targets 5α-reductase types 2 and 3 and is less effective than dutasteride in comparison—however, only finasteride is currently FDA-approved for the treatment of androgenetic alopecia. While Japan and South Korea have both approved dutasteride for the treatment of androgenetic alopecia, a dutasteride prescription for that indication in other countries would require a prescription for an off-label use.

Other generic compounds in the 5-ARI class of drugs include:

Table of known DHT inhibitors

How much does finasteride cost?

Depending on how you go about acquiring your prescription for finasteride and what type of insurance coverage you have, your costs may vary: If you opt for brand-name Propecia, you can expect to pay ~$120 per month for 30 1mg tablets, while generic finasteride clocks in at $20-80 per month for 30 1mg tablets. If you’re able to receive a prescription for generic finasteride at the level recommended to treat BPH, costs range widely from $3-154 per month for 30 5mg tablets, though insurance may help offset some of the higher costs. In addition, at the direction of your doctor, the 5mg tablets can be split into 1mg fragments, resulting in a better effective cost per month.


What is ProCelinyl?

ProCelinyl is the proprietary compound used in our Hair Revival Serum and Growth Concentrate—that means you won’t find it anywhere but here at Revela. When applied daily, our Hair Revival Serum and Growth Concentrate deliver power-packed ProCelinyl to the hair follicle to facilitate the appearance of thicker, fuller, healthier hair.

ProCelinyl forms the backbone of our topical Hair Revival Serum and Growth Concentrate. Unlike finasteride, which is taken orally in tablet form, ProCelinyl gets delivered directly to where you need it most: your scalp.

How does ProCelinyl work?

Research into hair loss has shown that as we age, changes to the hair follicle can negatively impact hair growth by altering the natural growth cycle of the follicle itself. We mentioned that DHT accumulation in the scalp around the hair follicles can lead to follicular miniaturization, eventually leading to thinning hair and hair loss. Another source of follicular miniaturization is a reduction in the number of dermal papilla cells (DPCs) at the base of the hair follicle.

Our in vitro studies showed that ProCelinyl directly targeted DPCs and increased their proliferation—or overall amount as a result of increased cell growth and division—by over 50%. Even better, ProCelinyl achieved these results without any off-target effects on other cell types.

When ProCelinyl advanced to trials in human volunteers, we found that after 6 weeks, 97% of volunteers saw improvements in their hair, while 87% saw a decrease in hair shedding without negative side effects.

Primary ProCelinyl in vitro data

How was ProCelinyl developed?

ProCelinyl was developed using an AI-guided compound discovery pipeline—put simply, we taught a machine to model and identify chemical compounds that might be successful at causing DPCs in the hair follicle to grow and grow faster. A smaller sample of those predicted compounds were screened and tested, then fed back into the machine learning algorithm to improve the results even further.

After tests for safety and efficacy, only one candidate remained as the best of the bunch: ProCelinyl.

Are there any comparable compounds to ProCelinyl?

Not really! Certain flavonoid compounds, like hesperetin, have shown efficacy as hair growth promoters by stimulating the proliferation of DPCs, but ProCelinyl behaves a bit differently. 

ProCelinyl has certain advantages over compounds like hesperetin, however. At equal concentrations, ProCelinyl outperformed hesperetin by tenfold. Further, while hesperetin broadly targets cell types like keratinocytes, endothelial cells, and DPCs, ProCelinyl was shown to only target dermal papilla cells.

As a topical, non-hormonal, direct-to-consumer option, we think ProCelinyl is blazing its own trail and carving out a unique niche in the cosmeceutical space for hair loss. 

How much does ProCelinyl cost?

As part of our Hair Revival Serum and Growth Concentrate, ProCelinyl is available at a range of price points and commitments. We offer one bottle of Hair Revival Serum—enough for one month of daily application—for $98, or a two-pack of Hair Revival Serum for $168 to streamline your hair growth journey after your first month. Both options are available as a recurring subscription for an additional 20% savings with each purchase.

If you’re looking for an ethanol-free solution, our Growth Concentrate for nightly spot treatments currently sells for $128 and is expected to last 2-3 months.

Once you’ve achieved the results you’re looking for, our serums and concentrates can be applied every 2-3 days instead of daily, meaning that each bottle stretches further. If you’ve subscribed to the Hair Growth Pack and you’re in the maintenance phase of your hair journey, that means you can expect to pay ~$22 per month. No appointments or health insurance necessary.

Compare & Contrast

That’s been a lot to take in, so let’s do a quick recap of the key differences between finasteride and our proprietary ingredient, ProCelinyl.

Woman holding Revela hair revival serum and woman holding pills

How finasteride and ProCelinyl work

Both compounds go about addressing hair loss, but they achieve their results in different ways.

Finasteride focuses on blocking the conversion of testosterone into DHT, which accumulates near the hair follicles in the scalp and leads to follicular miniaturization. Over time, this miniaturization results in hair thinning and eventually hair loss.

As part of our Hair Revival Serum, ProCelinyl works by targeting the dermal papilla cells in the base of the hair follicle, prompting them to proliferate more rapidly. This proliferation of the DPCs then leads to an increase in the appearance of thicker, fuller, healthier hair.

A key difference between the two that’s worth remembering: Finasteride is a hormonal solution, while ProCelinyl is not. As an oral medication that works systemically, finasteride can have some unpleasant side effects, including decreased libido, erectile dysfunction, and a host of mental health issues including depression, anxiety, and brain fog. Collectively, these symptoms fall under the umbrella of post-finasteride syndrome (PFS), an emerging condition that has led to lawsuits against the pharmaceutical company, Merck, accusing them of suppressing evidence.

If you’re concerned about undesirable side effects and prefer a targeted, topical approach, ProCelinyl may be right for you.

How finasteride and ProCelinyl were developed

Many scientific discoveries are made serendipitously, and the development of finasteride is such a story. Finasteride was developed following the publication of research on a group of intersex children in the Dominican Republic who shared a common genetic mutation that caused them to develop male sexual traits on a different timeline. Their shared mutation impaired the function of the enzyme 5α-reductase—which converts testosterone into DHT—and as a side effect, researchers noticed that the prostates of these children remained much smaller throughout adulthood. A researcher from Merck took notice of this effect, which led to the development of a drug that could mimic the genetic impairment in order to reduce the size of the male prostate in men who suffered from the condition benign prostatic hyperplasia (BPH). Over time, researchers noticed that men who were prescribed finasteride tended to regrow their hair. This led to the 1997 FDA approval for finasteride to treat a new indication: androgenetic alopecia, or male pattern baldness.

ProCelinyl, on the other hand, was developed from the beginning to target the hair follicle. We used a machine learning algorithm to target compounds that had been shown to have an effect on the hair follicle, narrowed down the results, tested them via high-throughput screening, then fed the results back into the algorithm to improve its output. The results were finally narrowed down, tested for safety and efficacy in vitro, then the winning candidate, ProCelinyl, was tried in human volunteers. After successful results, ProCelinyl was incorporated into our flagship product, Revela’s Hair Revival Serum.

Comparison chart of finasteride versus procelinyl

What do daily regimens with finasteride and ProCelinyl look like?

A daily regimen with finasteride involves taking a 1mg pill once daily. We discussed some of the costs above—though your time, effort, and cost when it comes to scheduling appointments and following up will certainly vary—but, now that finasteride is available in generic form, direct-to-consumer companies offer generic finasteride for hair loss at $22 per month. Using finasteride, in order to maintain any gains from the medication, you’re locked into using the prescription for as long as you want to keep your hair. And when it comes to side effects, we don’t want to attempt to quantify those and put a dollar value on them; however, we feel that some conditions, particularly post-finasteride syndrome, aren’t worth the risk.

As part of our Hair Revival Serum and Growth Concentrate, using ProCelinyl on a daily basis is as simple as applying it to problem areas on the scalp using our dropped and scalp massager. After you’ve achieved the results you’re looking for, you can taper your use of the Hair Revival Serum to every 2-3 days as you move into a maintenance phase. We’d also like to highlight the convenient cost comparison: As you enter the maintenance phase following the first few months of using Revela’s Hair Revival Serum with ProCelinyl, your cost could be as low as $22 per month—exactly what’s being advertised by the new direct-to-consumer wellness companies for generic finasteride, but with none of the systemic side effects. We like that comparison, and we think you will, too!

Click to see how ProCelinyl™ is changing how our customers view hair loss

Woman's hair, before and after


To tie it all together, finasteride and ProCelinyl both represent unique approaches to addressing hair loss issues. While finasteride is one of the two FDA-approved treatments for hair loss, it doesn’t come without its costs: Appointments, prescriptions, and side effects, which may or may not resolve should the medication be discontinued. ProCelinyl, on the other hand, is a topical solution that can be tailored to fit the results you’re looking for. Stay on the daily regimen for 6-8 weeks, or until you’ve seen the thicker, fuller hair you’re seeking, then dial back your regimen from every day to a few times each week to maintain your look.

When it comes to treating hair loss, we don’t like dealing with a litany of side effects from hormonal treatments—that’s why ProCelinyl takes a different approach and stays away from modulating the hormones in our body, instead focusing on targeting the hair follicle itself to achieve results. We think that comparison alone speaks for itself, but when you consider that using our Hair Revival Serum as part of our subscription model comes out to exactly the same monthly cost as using generic finasteride—without the hassle of appointments, side effects, insurance, or worries—we feel that ProCelinyl is an even more appealing choice.

What are you waiting for? Get going and start growing today!

Woman applying dropperful of serum to head

Profile photo for David Zhang

Reviewed by: David Zhang, PhD

David is an immunologist and bioengineer with over a decade of medical research experience. He completed his PhD at Harvard University, where he worked on developing life-saving cancer therapies. He received his undergraduate degree in immunology from McGill University and his master's degree from the University of Toronto

Written by: Revela Editorial Team

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