Encyclopedia of

Saw Palmetto (Serenoa repens)
Edward M. Croom, Jr.
School of Pharmacy, University of Mississippi, Oxford, Mississippi, U.S.A.
INTRODUCTION
Saw palmetto fruit extracts are frequently consumed
for relief of the lower urinary tract symptoms associated
with benign prostatic hyperplasia (BPH). The
most scientifically researched hexane and CO2 extracts
have been shown in clinical trials to be superior to
placebo and to have fewer side effects than a-blocker
and 5a-reductase inhibitor drugs for relief of symptoms
in men with mild to moderate BPH. Because there
are no current Food and Drug Administration (FDA)
guidelines or regulations on the labeling of saw palmetto
products regarding efficacy in improving prostate
health, consumers and health care professionals
must learn the scientific basis for their safety and effectiveness
claims to make an informed product choice.
BOTANY
Saw palmetto: Serenoa repens (W. Bartram) Small
Palm family: Arecaceae (also known as Palmaceae,
Palmae)
Botanical Synonyms
Corypha repens W. Bartram; Brahea serrulata
(Michaux) H. Wendland; Chamaerops serrulata
Michaux; Corypha obliqua W. Bartram; Sabal serrulata
(Michaux) Nuttall ex Schultes & Schultes f.;
Serenoa serrulata (Michaux) G. Nicholson.
Botanical Description
The stems of the palm are usually prostrate, branched,
and sometimes upright to a length of 3 m or more. The
stiff, fan-shaped leaves range in color from yellowgreen
to green and grayish green to silver-green
(Fig. 1). The saw-toothed (serrate) petioles are from
0.5 to 1 m long and have fine to coarse teeth that
account for the common name of this shrub-like,
branching palm. The flower stalks are approximately
Edward M. Croom, Jr., Ph.D., is Adjunct Associate Professor at
the School of Pharmacy, University of Mississippi, Oxford,
Mississippi, U.S.A.
the same length as the petioles. The small (4–5 mm),
fragrant, spring flowers are creamy white, with three
petals and six stamens. The pulpy, one-seeded fruits
ripen from green to orange to black or bluish black
(Fig. 2). Mature fruits are approximately 2 cm long
and 1 cm in diameter, with some fruits being similar
in shape and size to commercial black olives, having
a large hard seed inside the pulp. Flowering and fruit
production are highly variable each year; most fruits
mature in August and September. Saw palmetto is an
important wild plant providing food and cover for
many animals. The fruits are consumed by black bears,
white-tailed deer, raccoons, foxes, opossums, fish, and
many species of birds. [1–3]
Ecological Distribution
Saw palmetto is endemic to the southeastern United
States. The native range is from the coastal plain of
southeast South Carolina to Georgia, throughout the
state of Florida, including the Florida Keys, and to
the coastal plains of Alabama, Mississippi, and southeast
Louisiana. Saw palmetto is a major understory
plant, sometimes forming dense thickets in pinelands,
dunes, sand pine scrub, mesic hummocks, and woodlands
(Fig. 3). The plant is one of the most abundant
in Florida and is reported to be very well adapted to
surviving fires. [1–3]
PRIMARY USE
The main medicinal use of saw palmetto is for prostate
health and relief of symptoms of the lower urinary
tract that are associated with BPH, a condition that
is common in men over 50 yr of age. The only saw
palmetto fruit extracts that have been subjected to
multiple clinical trials in BPH are those produced
under highly standardized conditions, by extraction
with hexane or under hypercritical CO 2 conditions.
They have a chemical content of 85–95% fatty acids,
and have been stability tested to assure throughout
the shelf life that the chemical contents are sufficient
and that the capsules will disintegrate in conditions
that mimic the acidity of the stomach. Clinical trials
generally evaluated the ingestion of two 160 mg soft
gel capsules or one 320 mg capsule per day. The most
recent structured, evidence-based meta-analysis of
Encyclopedia of Dietary Supplements DOI: 10.1081/E-EDS-120022128
Copyright # 2005 by Marcel Dekker. All rights reserved. 635
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