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L-Histidine: Benefits, Side Effects & Dosage

L-Histidine: Benefits, Side Effects & Dosage


What is L-Histidine?

L-histidine (or simply histidine) was, until recently, considered to be a semi-essential amino acid. Its importance for children has been known for a long time, as it helps with growth and repair of tissue (x). However, it has recently been confirmed that histidine is also important for adults. This is because it is essential for the production of histamine (x).

Histamine is a vital chemical in the body. It is involved in digestion, breathing, immunity, sexual function and is also one of the brain’s key neurotransmitters (x). The discovery that L-histidine is vital for the production of histamine has raised its profile and elevated it to an essential amino acid.

The body uses histamine to manufacture myelin sheaths; these are the protective layers that surround the nerves in the body (x). The importance of histidine’s role in protecting the body’s nerves means that it is thought to provide some protection against the effects of degenerative neurological diseases, such as Alzheimer’s and Parkinson’s (x).

Histidine is also vital for making white blood cells (x). Its role with blood cell production means that it is important for maintaining a healthy immune system. It is also important for controlling the effects of inflammation in the body. This has led to it being used to help with the effects of arthritis and allergies (x).

Benefits of L-Histidine

Arthritis Treatment

Studies of rheumatoid arthritis show that there is a clear link between histidine levels in the blood and the onset of rheumatoid arthritis (x). This has led to research regarding the benefits of taking histidine for those suffering from pain caused by arthritis (x). So far, there is no clear answer regarding its effectiveness and it is likely to be an area for future research in years to come.

Histidine has a clear role in mediating the effects of inflammation in the body (x). This leads to another way in which it might be able to have a beneficial effect on the pain of arthritis. Having inadequate levels of histidine can cause increased inflammation (x, x). For those in the grips of arthritis, any further inflammation will cause a significant increase in pain.

Anemia Treatment

Anemia occurs when there are insufficient red blood cells in the body. This reduction in red blood cells means that there is not enough oxygen being transported to all the organs in the body, leading to fatigue, weakness, dizziness and shortness of breath (x).

Reduced levels of red blood cells can have a variety of causes (x). One of the reasons for anemia is that the body may be lacking the essential nutrients required to make red blood cells. The most common deficiencies being folate and B12. If anemia is caused by a deficiency in folate then taking a histidine supplement can alleviate the symptoms of anemia (x).

Taking a histidine supplement may help with anemia caused by folate deficiency (x). If you don’t eat a clean diet and you suffer from bouts of fatigue and dizziness, it might be worth considering a histidine supplement.

Alleviates Allergic Reactions

Histidine is a vital component for maintaining the balance of histamine in the body (x). Histamine is one of the main chemicals involved in allergic reactions. It is clear that low levels of histidine in the body can lead to more severe allergic reactions.

Histidine is often used as a treatment for people who suffer from extreme allergic reactions (x). If you do suffer from allergies, adding a histidine supplement to your diet may help to reduce the severity.

Reduces High Blood Pressure

Histidine has been shown to reduce blood pressure in patients who suffer from or are at risk from heart disease (x). The size of the effect was linked to the size of the dose. If you are considering taking more than 1g of histidine per day, you should first consult with your doctor (x).

As well as reducing blood pressure, histidine has been shown to be beneficial for heart function. Patients often take it before open heart surgery as it can reduce the need for other drugs and speeds the recovery of patients (x).

Skin Protection

There are a few substances that our bodies produce that can help protect us from the damaging effects of UV radiation. One of these chemicals is called urocanic acid (x). High levels of urocanic acid protect your DNA from UV radiation and can prevent the development of skin cancer.

Urocanic acid is produced from histidine (x). While taking a histidine supplement is in no way a replacement for sunscreen, it can provide you with an extra level of protection when you are out enjoying the sunny weather.

Sexual Pleasure

For some women who have difficulty achieving orgasm, the culprit could be histidine deficiency. Histamine is essential in order to achieve orgasm, so low levels can prevent it from happening at all (x). So if this is an area of your life that could use some help, adding a histidine supplement could make a world of difference.

In men, excessive levels of histamine can cause premature ejaculation (x). So you should always stick to the recommended dosage of histidine to avoid this.

L-Histidine Benefits

L-Histidine Side Effects

L-histidine is water soluble, which means that when you consume higher than normal levels of it, it can be excreted easily through sweat and urine. Because of this, there are no established maximum dosages for histidine. Taking up to five times the recommended dosage has no adverse effects (x).

One small study has shown that a small number of patients who took 20-60 times the recommended dosage suffered from side effects including headaches, nausea, confusion and depression (x). These effects have only been observed when extremely high doses of L-histidine have been taken.

For some people, adding L-histidine to their diet as a supplement can lead to some gastrointestinal discomfort. This is due to the pH of the supplements. Adding HCL to their supplement can often alleviate these issues.


Histidine should not be taken if you are on blood pressure medications. Be sure to consult a doctor first. It is unclear if histidine is safe for pregnant or breastfeeding women. For that reason, it is best to avoid supplementation.

In some cases, taking histidine supplements over a long period of time can lead to low levels of zinc and copper, so it is advisable to take these supplements along with histidine.

See Also
dicalcium phosphate

L-Histidine Dosage

The recommended daily dosage of histidine is 500 mg. Taking more the 1,000 mg is not advised.

L-histidine comes as a fine powder, which can easily dissolve into a drink. The powder does have a slightly bitter taste so you may wish to take it with a sweetened drink. It also dissolves better in warm liquids. You could take it with a bit of sugar in your morning cup of coffee.

Why Take L-Histidine?

Histidine plays a lot of important roles in the body. If you have a deficiency, it can cause wide-ranging problems. Symptoms include anemia, inflammation, poor hearing, reduced brain function, unhealthy skin and even anxiety (x, x, x, x). Adding a histidine supplement to your diet can protect you from these issues. It can even offer protection for your heart and skin.

Histidine levels can be low due to a lack of variety in your diet. They can also be low if food is not cooked with care. Because histidine is water soluble, it means that any foods cooked in water can actually lose almost all of their natural histidine. So even if you eat a lot of vegetables, you might still be low in histidine.

Another reason why you can end up with low levels of histidine is if you have low levels of vitamin B9 (folate/folic acid). When you are low in this vitamin, the body uses histidine instead. This can reduce its availability for other roles (x).

L-Histidine vs. L-Histidine HCL

When looking for histidine supplements you may have found that there are often two choices — L-histidine and L-histidine HCL. The difference between these two supplements is simply that one contains a small amount of HCL.

It might sound odd to add hydrochloric acid to a supplement, but for some people, it makes it easier to take the L-histidine. This is because histidine is an alkaline molecule and can upset digestion as it can have a neutralizing effect on stomach acid.

Both options will provide you with bio-available histidine. Which you want to take is a matter of preference. If you try L-histidine and it upsets your digestion then you can switch to the one with added HCL and vice versa.

The Bottom Line

L-histidine is an important molecule and having insufficient levels in the body can lead to a wide range of problems. Increasing your intake of histidine can provide you protection for your heart, skin and nerves. You can take it with or without HCL depending on your needs. It is a safe supplement to take and it is very hard to take too much. You may want to consider taking zinc and copper supplements alongside L-histidine.

By simply adding a little bit to a drink once a day you can reap the health benefits of this essential amino acid.

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