Description:
Epimedium is a genus of twenty-one related plant
species. The Chinese refer to epimedium as "yin yang
huo", which has been loosely translated by some as
"licentious goat plant" and explains why Western
supplement companies have adopted the titillating name
by which it is known in the U.S: (horny goat weed).
Epimedium is grown as an ornamental herb in Asia and
the Mediterranean region, and various species are used
for medicinal purposes, including Epimedium sagittatum,
Epimedium brevicornum, Epimedium wushanense, Epimedium
koreanum, and Epimedium pubescens.
Claims:
Because of the traditional use of epimedium for
treating fatigue and boosting sex drive, the majority
of the claims for Western dietary supplements center
around sex drive: · Boosts libido (sex drive)
· Increases energy levels · Enhances
recovery from exercise (via cortisol-control) ·
Makes you more sexy (not really, but this is what the
ads would suggest)
Theory:
The use of epimedium as a medicinal herb dates back to
at least 400 A.D., where it has been used as a tonic
for the reproductive system (boosting libido and
treating impotence) and as a rejuvenating tonic (to
relieve fatigue). Epimedium is thought to work via
modulation of cortisol levels (the primary stress
hormone). Under conditions of high stress, the
increased cortisol levels are known to cause fatigue
and depress sex drive - so bringing cortisol levels
back into normal ranges is also thought to help restore
normal metabolism, energy levels and libido.
Scientific Support:
Animal studies have shown that epimedium may function a
bit like an adaptogen (such as cordyceps, rhodiola,
ashwagandha, and ginseng) by increasing levels of
epinephrine, norepinephrine, serotonin, and dopamine
when they are low (an energy-promoting effect), but
reducing cortisol levels when they are elevated (an
anti-stress effect). There is also evidence that
epimedium can restore low levels of both testosterone
and thyroid hormone (bringing low levels back to their
normal levels) - which may account for some of the
benefits of epimedium in improving libido (sex drive).
Animal studies using epimedium have shown a reduction
in bone breakdown, an increase in muscle mass, and a
loss of body fat-each of which may be linked to the
observed return of abnormal cortisol levels back to
normal values (and rhythm). In a series of studies
conducted in humans and animals by Chinese researchers,
immune-system function was directly suppressed and bone
loss was accelerated, by using high-dose synthetic
cortisol (glucocorticoid drugs). Subsequent
administration of epimedium extract reduced blood
levels of cortisol and improved immune immune-system
function (in the humans) and slowed bone loss and
strengthened bones (in the animals).
Safety:
It is interesting to note that although at least 15
fifteen active compounds have been identified in
epimedium extracts, (luteolin, icariin, quercetin, and
various epimedins), many supplement companies currently
use alcohol extracts standardized only for high levels
of icariin. The traditional use of epimedium, however,
is as a hot-water decoction (tea), which would result
in a very different profile of active constituents when
compared to the high-icariin alcohol extracts that are
more commonly used in commercial products. Although at
least one test test-tube study has shown icariin to
protect liver cells from damage with by various toxic
compounds, other feeding studies (in rodents) have
suggested that high-dose icariin may be associated with
kidney and liver toxicity. There have been no reports
of adverse side effects associated with the traditional
preparation of epimedium (water-extracted) at the
suggested dosage (250 to 1,000mg per day).
Dosage: Because all of the existing scientific
evidence for the anti-stress and cortisol-controlling
effect of epimedium has been demonstrated for
water-extracted epimedium (that is, as a tea), and
because this form of extraction may result in a safer
form of epimedium (compared to the high-icariin alcohol
extract), it may be prudent to select supplements that
specifically use a more traditional formulation. There
have been no reports of adverse side effects associated
with the traditional preparation of epimedium
(water-extracted) at the suggested dosage
(250-1,000mg/day in 2-3 divided doses).
References:
1. Cai D, Shen S, Chen X. Clinical and experimental
research of Epimedium brevicornum in relieving
neuroendocrino-immunological effect inhibited by
exogenous glucocorticoid. Zhongguo Zhong Xi Yi Jie He
Za Zhi. 1998 Jan;18(1):4-7.
2. Chen MD, Kuang AK, Chen JL. Influence of
yang-restoring herb medicines upon metabolism of
thyroid hormone in normal rats and a drug
administration schedule. Zhong Xi Yi Jie He Za Zhi.
1989 Feb;9(2):93-5, 70.
3. Gau S, Fu D, Zhang H. Advances in the study on the
treatment of osteoporosis with Epimedium brevicornum
and its compound prescription. Zhongguo Zhong Yao Za
Zhi. 1999 Apr;24(4):249-51.
4. Gu Y, Meng G. Preparation conditions for decoction
of Epimedium grandiflorum Morr. Zhongguo Zhong Yao Za
Zhi. 1990 Jul;15(7):412-3, 446.
5. Kuang AK, Chen JL, Chen MD. Effects of
yang-restoring herb medicines on the levels of plasma
corticosterone, testosterone and triiodothyronine.
Zhong Xi Yi Jie He Za Zhi. 1989 Dec;9(12):737-8,
710.
6. Lee MK, Choi YJ, Sung SH, Shin DI, Kim JW, Kim YC.
Antihepatotoxic activity of icariin, a major
constituent of Epimedium koreanum. Planta Med. 1995
Dec;61(6):523-6.
7. Liang HR, Vuorela P, Vuorela H, Hiltunen R.
Isolation and immunomodulatory effect of flavonol
glycosides from Epimedium hunanense. Planta Med. 1997
Aug;63(4):316-9.
8. Liu ZY, Yang YG, Zheng B. Effect of improving memory
and inhibiting acetylcholinesterase activity by
invigorating-qi and warming-yang recipe. Zhongguo Zhong
Xi Yi Jie He Za Zhi. 1993 Nov;13(11):675-6, 646.
9. Peng G, Fu M, Zhang D. The experimental study about
the relations between Chinese herb-epimedium
leptorrhizum stearn (CH-ELS) and endogenous cAMP in
alveolar bone of orthodontic tooth in rats. Zhonghua
Kou Qiang Yi Xue Za Zhi. 1997 Jan;32(1):40-2.
10. Wu T, Cui L, Zhang Z, Chen Z, Li Q, Liao J, Huang
L. Experimental study on antagonizing action of herba
Epimedii on side effects induced by glucocorticoids.
Zhongguo Zhong Yao Za Zhi. 1996 Dec;21(12):748-51,
763.
11. Yu S, Chen K, Li S, Zhang K. In vitro and in vivo
studies of the effect of a Chinese herb medicine on
osteoclastic bone resorption. Chin J Dent Res. 1999
Feb;2(1):7-11.
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