Does Saw Palmetto Help Grow Hair?

In our latest question and answer, the pharmacist discusses the effectiveness of saw palmetto for hair loss.

Does Saw Palmetto Help Grow Hair?
Aug 19, 2019

Phyllis asked

I am wondering if you think starting to take Saw Palmetto it would help regrow some of my hair?

At a glance

  • Saw palmetto has mixed evidence for the treatment of androgenic alopecia (male or female pattern baldness).
  • Saw palmetto may inhibit an enzyme known as 5-alpha-reductase, and lower levels of DHT, an androgen. Excess DHT is associated is hair loss.
  • Some studies show positive effects, but it generally is not as effective as other treatments, such as Proscar (finasteride).
  • More studies are needed to further understand the potential risk and benefits of using saw palmetto for hair loss.


Saw Palmetto Stock Image

Saw palmetto is one of the most widely used natural supplements worldwide, with sales totaling over $700 in 2010 alone (over $200 million in the United States) and is consistently ranked in the top 15 botanical supplements in terms of sales volume.

It's most common use is for the treatment of BPH (benign prostatic hyperplasia) symptoms (e.g. trouble urinating).

Less commonly, it has been used to treat hair loss. Overall, research evaluating its effectiveness is mixed and contradictory. 

Some studies have shown some benefit for reversing hair loss, but only in certain situations. Specifically, it appears to only be potentially effective in treating androgenic alopecia, also known as male (or female) pattern baldness.

What Is Androgenic Alopecia?

Androgenic alopecia is a form of hair loss that is related to hormones, known as androgens. Androgens play an important role in both males and females, regulating hair growth, sex drive, and sexual development.

The androgen most-well associated with effects on hair growth is called dihydrotestosterone (DHT). Increased levels of DHT in hair follicles can lead to:

  • Shorter cycle of hair growth
  • Shorter hair growth
  • Thinner strands of hair
  • Delay in new hair growth after hair is shed

Studies show a reduction in DHT in hair follicles can reduce hair loss. A prescription drug, Proscar (finasteride), is FDA approved for the treatment of androgenic alopecia and works by reducing DHT levels.

How Saw Palmetto Works

Saw palmetto has a wide variety of effects, but what we will focus on here is its mechanism behind a potential reduction in hair loss.

Studies show that saw palmetto may have antiandrogen effects and, at least to some degree, inhibits an enzyme known as 5-alpha-reductase.

5-alpha-reductase is responsible for the conversion of testosterone to dihydrotestosterone (DHT).

Remember that high levels of DHT are associated with hair loss. Thus, a reduction in DHT may lead to less hair loss.

Since saw palmetto may inhibit 5-alpha-reductase, there would be less conversion of testosterone to DHT, which could potentially decrease hair loss.

Several studies have shown that saw palmetto works, at least somewhat, by this mechanism:

  1. Proscar Prescribing Information. AccessFDA
  2. Determination of the potency of a novel saw palmetto supercritical CO2 extract (SPSE) for 5α-reductase isoform II inhibition using a cell-free in vitro test system. PubMed
  3. Comparative effectiveness of finasteride vs Serenoa repens in male androgenetic alopecia: a two-year study. PubMed
  4. A randomized, double-blind, placebo-controlled trial to determine the effectiveness of botanically derived inhibitors of 5-alpha-reductase in the treatment of androgenetic alopecia. PubMed
  5. Botanical Bulletin On Saw Palmetto. American Botanical Council
  6. Leading Saw Palmetto Producer Reports That Consumers May Be Using Saw Palmetto Incorrectly in Support of Prostate Health. PRN News Wire

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