How Saw Palmetto and Finasteride Fight Hair Loss

February 5, 2023 Dr. Steven Shapiro

Hair loss is frequently a result of hormones and your genes. Yes, blame your parents: most hair loss is hereditary in natur, and male hormones (which we all have, even the ladies) are largely to blame for thinning hair, bald patches, and nonexistent growth.

Pattern baldness, or androgenic alopecia, happens to both men and women because both sexes produce the primary hormones that affect hair growth, testosterone and dihydrotestosterone (DHT).

Saw palmetto and finasteride are two potent ingredients in the battle against hair loss for one simple reason: they both block the notorious hair loss hormone DHT. But how do they work, and how does naturally-occuring saw palmetto stack up vs. finasteride?

Understanding the process that leads to hair loss is the first step in comprehending why these two substances have become key players in restoring great hair.

Why Does Hair Loss Happen?

The most common form of hair loss is androgenic alopecia. The name is derived from the hormones that play a significant role in the hair loss process: androgens. Androgens are a group of hormones that are primarily associated with male sexual reproduction and masculine traits; however, this group of messengers regulates a whole host of bodily processes, and women need and naturally produce them too. True, men have higher levels of androgen hormones than women, part of the reason that men are more frequently impacted by baldness and that women with androgenic alopecia rarely go completely bald.

The two androgens connected to hair loss are testosterone and dihydrotestosterone. Though both are androgens, DHT is actually derived from testosterone. It is the DHT – frequently called the hair loss hormone – that has a direct impact on hair loss. Without testosterone, however, you wouldn’t have DHT.

How DHT Is Formed

DHT is the most powerful male steroid hormone. An enzyme called 5-alpha reductase is responsible for converting testosterone into DHT naturally in the body. The process occurs in your liver, skin and hair follicles. In men, it also happens in the prostate. Interestingly, while the hormone is responsible for hair loss on your head, it also causes hair growth on other areas of your body, such as the back and chest.

How Hair Grows

The skin on your head (and other parts of your body) contains shafts called follicles. Each one of these follicles produces a single strand of hair. The strands of hair go through two- to six-year growth cycles. Cutting or shaving does not interrupt this cycle; the same strand of hair continues to grow through the rest of its cycle.

At the end of the growth cycle (called the anagen phase), the follicle enters a resting phase (called the catagen phase) that typically lasts a few weeks or months, followed by the telogen phase, when the hair detaches and falls out of the follicle.

The follicle begins the process all over again, growing a new strand of hair.

How DHT Causes Hair Loss

Androgenic alopecia is a genetic condition, meaning the tendency for male- and female-pattern baldness is passed down from one or both parents (not just through the female line, as is commonly believed) through the androgen receptor gene.

For those with androgenic alopecia, alterations to the AR gene produce variations in the androgen receptors — a type of protein — on the scalp.

DHT binds to these receptors, causing the hair follicles to shrink. It also shortens the growth cycle and lengthens the resting phase for each follicle. This miniaturization process weakens the follicles and may eventually lead to the cessation of hair growth on every follicle containing bonded DHT.

The degree of hair loss depends on how many receptors exist on different parts of the scalp. The more receptors there are, the more DHT can bind to them, thus inhibiting the hair growth cycle in those areas.

Saw palmetto and finasteride can affect this process and are both used to treat androgen-related hair loss conditions, such as androgenic alopecia, the most common form of hair loss in men and women.

How Does Saw Palmetto Help With Androgenic Alopecia?

Saw palmetto extract comes from the berries of the dwarf palm Serenoa Repens, a native tree found in the Southeastern region of the U.S. The extract is used in both topical and oral medications to treat hair loss. Saw palmetto is 70%-90% fatty acids. It also contains beta carotene, phytosterols, polysaccharides and derivatives of vitamin E.

Saw Palmetto’s Effect on DHT

Saw palmetto interacts with the 5-alpha reductase enzyme, which comes in two isotopic forms (Type I and Type II) to inhibit the conversion of testosterone to DHT. It works on both enzyme forms and results in an almost 50% reduction in the binding of DHT to androgen receptors. The fatty acids in saw palmetto are also responsible for the positive effects this natural ingredient has on androgenic alopecia because they:

Encourage the naturally selective process for converting testosterone to DHT
Directly inhibit 5-alpha reductase function
Impact the conformational stage of 5-alpha reductase

Saw palmetto also affects 3-alpha-hydroxysteroid-dehydrogenase, an enzyme that converts DHT into the weaker androstanediol metabolite. Its interaction with this enzyme leads to an increase in the conversion process, resulting in lower DHT levels. This process is another way in which saw palmetto reduces the availability of DHT to bind to androgen receptors.

Saw Palmetto’s Impact on Hair Loss

Saw palmetto’s effect on DHT has an overall positive impact on hair follicles. The inhibition of the 5-alpha reductase enzyme can slow the further progression of androgenic alopecia due to the reduction in how much testosterone the enzyme converts to DHT. Furthermore, research demonstrates that topical application can improve hair count, resulting in a fuller head of hair.

How Does Finasteride Help With Androgenic Alopecia?

Finasteride is one of two drugs approved by the U.S. Food and Drug Administration to treat androgenic alopecia. Like saw palmetto, finasteride can be taken orally or used as a topical medication. It is a synthetic medication produced in a lab.

Finasteride’s Effect on DHT

Finasteride is another 5-alpha reductase inhibitor. Unlike saw palmetto, which affects both Types I and II isotope forms, finasteride only affects Type II isotypes. Finasteride interrupts this conversion process, inhibiting DHT production and resulting in lower levels of the hormone in both the blood and tissues. Finasteride can reduce circulating DHT by as much as 85%.

Finasteride’s Impact on Hair Loss

Finasteride works quickly to reduce the blood concentration of DHT. Within 24 hours of patients taking 1 milligram of the drug (the approved dose for hair loss), their DHT levels typically drop by 65%. Finasteride does not have any effect on androgen receptors. As the drug affects the conversion of testosterone into DHT in the blood and tissues, it reduces how much DHT is available to bind to androgen receptors on your head. It isn’t selective, so you should see improvements all over your scalp.

Taking finasteride also has an impact on hair growth. Studies show that 83% of those who take the drug experience no further hair loss. Moreover, 45% also see improvements in hair growth after one year, and 66% see improvements after two years of taking the drug.

Conclusions

Saw palmetto and finasteride both work to inhibit the 5-alpha reductase enzyme, preventing the conversion of testosterone into DHT. There are a few differences in how the two work, but each can be effective in fighting androgenic alopecia. Women should not use finasteride, and oral saw palmetto may also be dangerous, particularly for pregnant women or those who intend to get pregnant, as DHT inhibition can affect fetal development. In fact, finasteride is not approved for use in women.

At Shapiro MD, our dermatologist have found that saw palmetto and finasteride both have a place in the arsenal against hair loss. Saw palmetto extract is a key ingredient in our flagship shampoo, conditioner, and other topical formulations, which contain DHT-fighting EGCG as well as caffeine to boost hair health and scalp DHT defense. Finasteride is a potent solution for many men dealing with hair loss, too, helping them get a more dense head of hair and even regrow new hair.

If you’re concerned about hair loss, take our free quiz to find a solution that works for you. Affordable and easy-to-use, Shapiro MD has helped more than 300,000 men and women start their hair growth journey.