- Training Reference Notes

Health and nutrition education and training for Quest stockists and consumers.

Produced by the Nutrition Department, Quest Vitamins Limited,
Birmingham, B7 4AP, Tel: 0121 359 0056, Fax 0121 359 0313, e-mail:
Quest Vitamins Ltd. 2001 - No reproduction of material without permission from Quest Vitamins Ltd.



Caused by a wide variety of factors, fatigue is characterised as a persistent feeling of tiredness. Usually a symptom of an underlying disorder, fatigue can result from viral or bacterial Infection, a suppressed Immune System, Depression, a hormonal imbalance, oxidative Stress, and nutritional deficiencies, among many others.

There are three basic types of fatigue: acute, with a sudden onset and cured by rest; chronic, which is a lasting fatigue and is most likely a symptom of a more serious disorder; and muscular, which results from working the muscles to exhaustion.


Liquorice (3)
Ginkgo biloba (7)
Ginseng (6)
Gotu Kola (5)


B Complex (2)
Brewer's Yeast
Magnesium (1)
Thiamine (4)
L-tyrosine (8)


1. Cox IM, Campbell MJ, Dowson D. Red blood cell Magnesium and Chronic Fatigue Syndrome. Lancet 1991;337:757-60.
2. Kaufman W. The use of vitamin therapy to reverse certain concomitants of Aging. J Am Geriatr Soc 1955;3:927-36.
3. Baschetti R. Chronic Fatigue Syndrome and Liquorice. New Z Med J 1995;108:156-57.
4. Suzuki M, Itokawa Y: Effects of Thiamine supplementation on exercise-induced fatigue, Metabolic Pr Brain Dis, 11(1), March 1996, 95-106.
5. Ramaswamy AS, et al: Pharmacological studies on Centella asiatica, Jour Res India Med, 1970, 4:160-75.
6. Bohn B, et al: Flow-cytometric studies with Eleutherococcus senticosus extract as an immunomodulatory agent, Arzneimittel-Forsch, 1987, 37:1193-96.
7. Krieglstein J, et al: Influence of an extract of Ginkgo biloba on cerebral blood flow and metabolism, Life Sci, 39(24), Dec 1986, p 2327-2334.
8. Mouret J, et al: Treatment of narcolepsy with L-tyrosine, Lancet, 2(8626-8627), Dec 1988, p 1458-1459.