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Quest Vitamins LTD,
8 Venture Way,
Aston Science Park,
B7 4AP.

Tel: 0121 359 0056
Fax: 0121 359 0313
Registered in England No. 2530437



L- & DL-Phenylalanine

L-phenylalanine is an essential amino acid, which means the body needs a regular dietary supply of it. DL-phenylalanine (DLPA) is a mixture of the naturally occurring L- form together with the mirror image D- form of phenylalanine. Whilst D- form Amino Acids do not normally have uses in the human body, D-phenylalanine is a notable exception.


L-phenylalanine is a component of dietary proteins and is also the precursor of many non-essential Amino Acids in the body. A number of neurotransmitters (brain chemicals) are derived from L-phenylalanine; this amino acid also stimulates the release of a hormone that controls the appetite.

D-phenylalanine has certain unique properties, the major one of which is Pain relief. D-phenylalanine is thought to be able to relieve pain by slowing the breakdown of the body?s own morphine-like pain killing substances called endorphins.

Endorphins also have a slight euphoric effect and are thought to be produced after eating - hence the desire to binge in many depressed people.


L-phenylalanine may be taken in supplement form as a mild anti-depressant, to generally lift the mood and increase mental alertness. L-phenylalanine is able to have this effect by stimulating the production of certain excitatory neurotransmitters (1).

Appetite Control:
Practical experience has shown that L-phenylalanine may be taken to help suppress the appetite in people who generally eat too much for their needs and who are obese.

The combination supplement DLPA can help to relieve chronic prolonged pain, for example the pain of Arthritis (1).

For people with food cravings, DLPA supplements can also be very useful, because endorphins stimulated by DLPA bring a feeling of satisfaction and decrease the desire to binge.

The uses of L-phenylalanine and DLPA obviously overlap quite a lot, but in the case of pain or food cravings (as opposed to sheer over-eating) DLPA is the supplement of choice.


Up to 6g per day of L-phenylalanine or DLPA per day is regarded safe, but only 500-1500mg per day is normally recommended for self-administration. Higher levels should be taken under medical supervision.


MAO inhibitor anti-depressant drugs:
L-Phenylalanine and DLPA should not be taken by those on MAO inhibitor anti-depressant drugs.

Both Amino Acids should also be avoided by pregnant women, schizophrenics and those with high blood pressure.


1. "The Healing Nutrients Within", E R Braverman & C C Pfeiffer, Keats, 1987.

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