Product Information

Synonyms: acetyl-L-tyrosine, acetyltyrosine

Keywords: neurotransmitters, mood, depression, hair color, skin color, vitiligo, blood pressure, Parkinson’s


The amino acid L-tyrosine is a precursor for several substances made in the body:

  • neurotransmitters such as dopamine and norepinephrine1
  • melanins, the pigments largely responsible for skin and hair color2,3,4
  • thyroid hormones, such as thyroxine5

N-acetyl-L-tyrosine, which is converted in the body to L-tyrosine, is 20 times as soluble in water as L-tyrosine itself. For this reason, it serves as an efficient supplement for raising tyrosine levels in the body, since undissolved substances are not absorbed from the digestive tract. Our product also contains vitamin B-6 — a required cofactor for neurotransmitter synthesis.

What we can’t tell you

In the U.S. and some other industrialized countries, government agencies like the U.S. Food and Drug Administration have adopted censorship as a method for intensifying their control over the supplement industry and its customers. Thus, FDA regulations prohibit us from telling you that any of our products are effective as medical treatments, even if they are, in fact, effective.

Accordingly, we will limit our discussion of N-Acetyl-L-Tyrosine to a brief summary of relevant research, and let you draw your own conclusions about what medical conditions it may be effective in treating.

Most of the medical research relating to tyrosine supplementation has been conducted using L-tyrosine itself, not acetyl-L-tyrosine. It is logical to assume, however, that the conclusions reached will apply to acetyl-L-tyrosine as well, since the latter is converted to L-tyrosine in the body. The following discussion therefore draws from studies of L-tyrosine.

Mood and depression

Chronic mild stress can cause neurotransmitter deficiencies, leading to depression or sullen moods.6,7 Tyrosine supplementation elevates neurotransmitter levels, cures certain kinds of depression,8 alleviates others,9 and can improve mood.10

Hair and skin color

Although, in theory, tyrosine supplementation should promote melanin production in human skin, no clinical studies have been performed to test this concept directly.11 On the other hand, the closely related amino acid L-phenylalanine has been shown to restore skin pigment in cases of vitiligo — a localized loss of skin pigment.12 In the body phenylalanine is converted to L-tyrosine, which suggests that L-tyrosine supplementation would have produced similar results.

Tyrosine has been tested In cats as an oral supplement in combination with phenylalanine and found to be an effective hair darkening agent.11

Melanin production in the human body can also be stimulated by certain antioxidant supplements. For example, either of the following two antioxidant regimens have been found to increase melanin in skin without UV exposure:13

  • 13 mg of beta-carotene, 2 mg of lycopene, 5 mg of vitamin E and 30 mg of vitamin C
  • 3 mg of beta-carotene, 3 mg of lycopene, 5 mg of vitamin E and 30 mg of vitamin C.

Such combinations of antioxidants may therefore be considered candidate regimens for enhancing the effects of tyrosine supplements on skin and hair pigmentation. Another supplement with a reported ability to darken the skin is piperine.14

Blood pressure

Stressful conditions often raise blood pressure. Such rises have been experimentally suppressed by L-tyrosine supplementation.10 On the other hand, chronic high blood pressure does not appear to respond to this treatment.15

Parkinson’s Disease

Acetyl-L-tyrosine is sometimes used by Parkinson’s patients to boost concentrations of the neurotransmitter dopamine in the brain, while avoiding the side effects of taking such dopamine precursors as L-dopa. A small clinical trial in the 1980s compared the use of L-tyrosine to L-dopa, and the researchers concluded that “For some patients, 3 years of L-tyrosine treatment was followed by better clinical results and many fewer side effects than with L-dopa or dopamine agonists.”16 This approach has not been followed up with further clinical studies.


Are N-Acetyl-L-Tyrosine supplements useful for the conditions and purposes mentioned above? We aren’t allowed to tell you, so you should take a look at some of the references cited here, and then decide for yourself.

30520 300 mg 90 capsules 1 capsule $11.70
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Pronunciation: acetyl a·sēʹ·təl, tyrosine tæʹ·rō·sēn

— RM

Last modified 2010.08.30