Saw Palmetto is a supplement with potentially beneficial properties for human health: such as reducing symptoms of benign prostatic hyperplasia and preventing hair loss.
What is Saw Palmetto and how is it obtained?
Saw Palmetto is a supplement that’s produced from the fruits of the Serenoa Repens plant
It’s an oily compound formed by a great variety of bioactive substances, including esterified fatty acids (triglycerides, mainly) and free fatty acids (oleic, lauric and myristic fatty acids); phytosterols, flavonoids, polysaccharides and amphipathic alcohols.
The truth is that the active ingredients of Saw Palmetto, as well as its mechanism of action, are not fully known, as they don’t really act in a single way.
To clarify this, which was completely unknown until about a decade ago, Masayuki et al. (2009) isolated the principles found in a Saw Palmetto supplement to see which of them presented the mechanism of action that makes Saw Palmetto such an effective product for the treatment of the aforementioned pathologies.
And they discovered that the oleic acid found in the supplement was the substance that principally produced the desired effects; lauric and myristic fatty acids also shared the same mechanisms, but their affinity was less.
What is Benign Prostate Hyperplasia?
Benign prostate hypertrophy (hyperplasia) (BPH) is one of the most common potentially pathologic conditions in middle- and older-aged men
It’s one of the main causes of development of lower urinary tract symptoms (LUTs), such as:
- Incomplete emptying of the bladder
- Elevated urinary frequency
- Intermittence in the process
- Sudden urge to urinate
- Low pressure in urination
- Requirement of high efforts to initiate and maintain urination
Why does this happen?
Benign prostate hyperplasia is influenced by a large number of factors that condition the prevalence of the disease, from age, race, genetic factors that predispose to the growth and proliferation of prostate cells, to environmental factors.
In turn, there is a direct correlation between BPH-Metabolic Syndrome-LUTs-Erectile Dysfunction. Making those who suffer from obesity or being overweight, diabetes and alterations in glucose metabolism, and dyslipidemia, may suffer from these pathological conditions.
Figure I. Graphic representation of the anatomical structure of the urogenital system with a normotrophic prostate and BPH. Source: https://es.wikipedia.org/wiki/Hiperplasia_benigna_de_pr%C3%B3stata
What are the symptoms of an inflamed prostate?
In addition, despite the extensively established correlation in literature between BPH and erectile dysfunction, the mechanisms by which BPH can affect penile erectile capacity have not been unanimously established.
At what age does it occur?
If we combine all this and mix it, in the end we obtain epidemiological statistics on BPH that show an increase in the development of the condition from the age of 40, presenting a prevalence between 8-60% in elderly adults (Lim, 2017)
Incredible as it may seem, there is a compound capable of acting in all ways that interrelate these 4 processes: BPH, LUTs, erectile dysfunction and age-related alopecia.
Saw Palmetto on the pathophysiology of BPH and LUTs?
There are 2 great mechanisms that condition the appearance of BPH and therefore LUTs
First of all, the concentrations of dihydrotestosterone in males (it’s also the mechanism directly linked to alopecia), which is also the main trigger for BPH.
Secondly, all the mechanisms related to the contraction of prostate tissue, which consists of the continuous overactivation of the prostate through mechanisms dependent on the release of calcium that generate a narrowing of the urethra duct by compression when the contracted prostate tissue is found.
Dihydrotestosterone (DHT) is the reduced form of testosterone
This is produced by a conversion process mediated by two isoenzymes called 5-alpha-reductase type 1 and type 2. Both act the same, but the distribution in the tissues is different; with those of type 2 predominating in the prostate and the hair follicle of the scalp; and we also have type 3, but its influence on these aspects is less.
The DHT that is generated in the prostate binds to the androgenic receptor of the smooth cells present in the tissue, leading to a whole process of transcription and translation of the genetic code that leads to cell proliferation (hyperplasia) and therefore enlargement of the prostate.
Figure II. Genomic signalling by which DHT agonises the androgenic receptor (AR) and initiates the process of genetic transcription leading to cell proliferation. (Liao et al. 2013)
The traditional treatment to avoid this cell proliferation is the reversible inhibition of the action of the enzyme 5-alpha-reductase in those who for some reason have a mutated genotype that overactivates this enzyme; finasteride or duasteride will sound familiar to many people, as they’re drugs that inhibit the action of different isoenzymes.
Saw Palmetto acts in the same way as duasteride, inhibiting both types of reducing isoenzymes, which is extremely effective in inhibiting reductase activity.
Figure III. Graphic representation of the effects of Saw Palmetto extract on the inhibition of the enzyme 5-alpha-reductase, the inhibition of its coupling to the androgen receptor and the anti-inflammatory and apoptotic effects on prostate tissue smooth cells by this (Suzuki et al. 2009)
Here we can see that the treatment with Saw Palmetto, at a concentration of 3.58mcg/ml, inhibits half the activity of the enzyme; at a concentration of 10mcg/ml, the inhibition is 90%.
Figure IV. Percent inhibition of the enzyme 5-alpha reductase (Mean Inhibition (%)) based on the concentration of Saw Palmetto in the medium (Concentration (mcg/mL) in vitro (Pais, Villar & Rull., 2016)
To avoid making the article longer than necessary, Saw Palmetto lipoesterols act on the inhibition of tissue muscarinic receptors, inhibiting alpha-1 adrenergic receptors present in the prostate and blocking 1,4-dihydropyridine receptors in prostate tissue cells.
Explaining each mechanism individually is a long and complex process, but what’s important to understand is that:
- Alpha-1 adrenergic receptors respond to catecholamines (adrenaline and norepinephrine)
- Muscarinic receptors respond to acetylcholine
- 1,4-dihydropyridine receptors respond to pyridine
It is more or less similar to the process by which a bicep contracts, although slightly different as the prostate tissue is smooth muscle and not striated; that contraction narrows the transit area of the urethra through the prostate and hinders the urination process.
Figure V. Molecular signalling pathway leading to muscle contraction. Source: https://cvphysiology.com/Blood%20Pressure/BP026
Saw palmetto and Tamsulosin
For example, Tamsulosin, which is one of the most prescribed drugs to cope with LUTs produced by BPH, is based on the antagonisation of alpha-1 adrenergic receptors to prevent involuntary contraction of prostate tissue; just as Saw Palmetto acts.
Saw palmetto and Erections
Finally, and although this is anecdotal, Saw Palmetto has been used for decades as an aphrodisiac and invigorator, and this is because it shares the same mechanism of action as drugs such as Sidenafil (Viagra, Kamagra…) and is its inhibitory activity on PDE5
Figure VI. Regulation of smooth muscle, phosphodiesterase 5 (PDE5) and its effects on the inhibition of muscle relaxation. (Cobin, 2004)
PDE5 (phosphodiesterase 5) is an isoenzyme of the phosphodiesterase superfamily that is expressed in tissues such as the brain, lungs, or bladder and smooth muscle.
PDE5 is an enzyme that degrades cGMP (cyclic guanosine monophosphate), which acts as a messenger when nitric oxide reaches muscle tissue.
Saw palmetto Daily dose
Yang et al. (2013) showed how Saw Palmetto extract decreased PDE5 activity in a dose-dependent manner , reaching its maximum inhibition at 5.716mg/kg.
Figure VII. PDE5 activity as a function of the dose of Saw Palmetto extract (SPE) in rats. (Yang et al., 2013)
Remember that these doses are not extrapolable to humans and in no case should you exceed 320mg of Saw Palmetto Extract with a fatty acid content of 80-90%
Saw Palmetto extract showed a greater amplitude (erectile activity) in a dose-dependent manner; like sidenafil; its magnitude came to be equated with that of sidenafil at its highest doses.
Figure VIII. Comparison between penile erectile response following administration of electrical stimulation following administration of different doses of sidenafil (A) and Saw Palmetto extract (B) in rats. (Yang et al., 2013)
Buy Saw palmetto
Buy Saw Palmetto Supplements at the best price possible with HSN
Each veg pearl (one of the few manufacturers that offers a softgel of non-animal origin) provides:
- 320mg of Saw Palmetto Oil
- 80mg of Pumpkin Seed Oil
Forming an excellent formula for human health, with 85% unsaturated fatty acids, which, as we have seen, and according to research: oleic acid and lauric acid inhibited 5a-reductase.
- Corbin, J. D. (2004). Mechanisms of action of PDE5 inhibition in erectile dysfunction. International Journal of Impotence Research, 16 Suppl 1, S4-7.
- Liao, R. S., Ma, S., Miao, L., Li, R., Yin, Y., & Raj, G. V. (2013). Androgen receptor-mediated non-genomic regulation of prostate cancer cell proliferation. Translational Andrology and Urology, 2(3), 187–196.
- Pais, P., Villar, A., & Rull, S. (2016). 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. Research and Reports in Urology, 8, 41–49.
- Suzuki, M., Ito, Y., Fujino, T., Abe, M., Umegaki, K., Onoue, S., … Yamada, S. (2009). Pharmacological effects of saw palmetto extract in the lower urinary tract. Acta Pharmacologica Sinica, 30(3), 227–281.
- Yang, S., Chen, C., Li, Y., Ren, Z., Zhang, Y., Wu, G., … Yao, M. (2013). Saw palmetto extract enhances erectile responses by inhibition of phosphodiesterase 5 activity and increase in inducible nitric oxide synthase messenger ribonucleic acid expression in rat and rabbit corpus cavernosum. Urology, 81(6), 1380.e7-13.
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