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L-Tyrosine Review – 8 Things You May Not Know

By Sasha de Beausset Aparicio, MSc

Reviewed by Rebecca Williams, MD, MA, MB, BChir

Last Updated:

Evidence Based | Summary | Nutrition Info | Claims | Cautions | Cost | Dosing | Bottom Line

L-Tyrosine is one of the 22 amino-acids present in the human body, being categorized under the non-essential ones, as a derivative of Phenylalanine. It is used to reduce stress levels, reduce fatigue and increase focus and memory capacity.

This supplement is recommended for people undergoing stress, sleep deprivation, extended periods of emotional distress or prolonged intellectual effort. It claims to regulate hormone levels and neurotransmission, influencing dopamine levels in the human brain.

As with many amino-acid based supplements, L-Tyrosine is considerably sought-after, with people taking comfort in the fact that the substances contained in the product already exist in the human body and by ingesting them they simply increase existing amounts of it, rather than introduce a new element. Also, there is a low number of reported side-effects for this type of supplements, which increases the popularity of such products.

It is due to this popularity that there are numerous manufacturers currently producing and supplying L-Tyrosine. When deciding to try this product, we advise you to research into manufacturers’ reputation and history on the market, as well as inquire about free trials or refund possibilities.


1) What is L-Tyrosine?

The active ingredient in L-Tyrosine is the homonym amino-acid, one of 22 of the ones present in the human body, and one of 14 that are not essential. L-Tyrosine is considered non-essential because it is a derived from Phenylalanine, an essential amino-acid used in supplements as an analgesic and antidepressant.

Unlike its precursor, Tyrosine has little analgesic properties; it has, however, been proved to have antidepressant and regulatory properties. The major downfall of this substance is the fact that it only seems to have effects on people that are already undergoing stressful, tiring or emotionally charged situations; the preventive capacity of this amino-acid is considerably low.

In people that are experiencing the above-mentioned situations, Tyrosine reduces stress hormone levels, weight-loss caused by stressful situations and improves cognitive performance. This is due to the increased dopamine levels that the amino-acid helps synthesize, dopamine being a neurotransmitter with vital importance to the proper functioning of the human brain.

Nutrition Info

2) Ingredients of L-Tyrosine

L-Tyrosine contains: L-Tyrosine, Gelatin, Silica, Vegetable Magnesium Stearate.

3) Is L-Tyrosine Right for You?

L-Tyrosine is a non-essential amino acid that helps to build protein. It is derived from Phenylalanine which is an essential amino acid. However, it does assist with the structure of other proteins in the body. L-Tyrosine is also believed to assist with various chemicals that are in the brain, and it’s probably from this belief that the miraculous effects come from. L-Tyrosine isn’t your average supplement, that you could find just off the shelf and that you should start to take, though. In fact, many experts believe that it isn’t a good idea to take L-Tyrosine unless the doctor has given consent to do so but you can buy it over the counter without any prescription.

To make the average consumer understand where L-Tyrosine naturally comes from, they must first know that a healthy, balanced diet helps produce the amino acid, if, for example, you have a high intake of fish, meat, oats and other foods that are high in proteins. The problem with this is, some concentrate on consuming too much of only one produce and neglect the concept of generally having a diverse diet, which usually leads to high cholesterol and a lack of L-Tyrosine.

Some studies indicate a lack of this amino acid may be a reason for depression in some individuals. It is also claimed that when there isn’t enough of it in the body, then the kidneys may not function as they should. Many claims need to be carefully looked into before agreeing to purchase and take the product, but either way, you should consult a doctor beforehand. An expert will tell you that you may take no more than 150 mg of L-Tyrosine per day as it may cause: nausea, vomiting, fatigue, headaches, heartburn, and pain in the joints.


4) L-Tyrosine Claims

  • all of the ingredients are natural.
  • product is suitable for vegetarians.
  • effects of the supplement are medically attested.
  • little reported side-effects.


5) What You Need to Know Before Taking L-Tyrosine

  • effectiveness of supplement is determined by existing conditions (other ingredients, concentration,strengths, manufacturer).
  • no preventive use.
  • caution is required with dosage to prevent side effects.


6) L-Tyrosine Cost

Usually found at a moderate cost of $18 or more, L-Tyrosine’s price will depend on the amount the person is taking. It is recommended to compare more than just price, though. The reputation of the company is also an important factor that plays a role in convincing users of the product’s value.

The use of L-Tyrosine is somewhat of a controversial subject these days, and unlike some supplements, it may be harder to find online than at retailers. Still, there are quite a few locations where these products can be purchased online.


7) L-Tyrosine Serving Size

The recommended dose for L-Tyrosine is 100mg daily, while the maximum suggested dose is 150mg. Exceeding this amount can lead to negative side-effects such as nausea and vomiting, joint pains, headaches and heartburn. Excessive amounts of the supplement have also been shown to reduce dopamine levels, leading to the effects opposite to those required.

Bottom Line

8) The Bottom Line – “Does it Work?”

L-Tyrosine is one of many products available that claim to help people that are undergoing stressful situations; however, it is one of few that only have effect if the person is already experiencing stress, with the advantage that its effects are medically attested.

The large amount of manufacturers points towards the popularity that this product has, fact that supports testimonials regarding the effectiveness of this supplement. It also presents the disadvantage that potential consumers have to conduct their own research into the companies, deciding for themselves who to place their trust with.

Research is advised regarding the product itself as well, seeing as different people have different needs. Before deciding to try L-Tyrosine, it is advised you consult your doctor regarding consumption and dosages.

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My holistic psychiatrist prescribed L-Tyrosine (Metabolic Maintenance for pill form, NeuroScience for the liposomal spray form which doesn’t need to be taken on an empty stomach) for my ADD. It has definitely helped my focus and I am now off of the amphetamine I was previously taking for my ADD. I have to say it is wonderful when compared to taking the powerful pharmaceutical drugs and doesn’t have all the side effects or make me feel “drugged up”. But I am going to take this advice for amino acid proteins to heart and will try to reduce my sugar intake and increase proteins, as I’ve always tended to consume too much sugar and not enough protein.