L-Arginine is a very popular supplement, often found in preworkout products.
It is known by bodybuilders and athletes to boost performance and build muscle.
Doctors use it to treat problems with the heart and circulation.
But, reliable information on dosage and effects can be hard to find.
We’ve put together this guide to help you discover more about this well-known supplement so that you can make an informed choice.
What is L-Arginine?
L-Arginine, sometimes referred to as simply ‘Arginine’, is a conditionally essential amino acid.
Amino acids are the building blocks of all proteins in the body.
Some amino acids can be produced naturally in the body from other chemicals, while some need to be taken in as part of a healthy diet.
Amino acids which we need to consume from food in order to stay healthy are known as essential amino acids.
The reason that arginine is known as ‘conditionally essential’ is that some people are unable to make it in their body.
This includes very young (and pre-term) babies and people suffering from kidney problems or other serious illnesses.
Most healthy adults will be able to produce adequate supplies in the liver.
But what’s the purpose of L-Arginine?
Arginine contributes to many processes within the body.
Such as: rapid wound healing, removing ammonia, cell division, correct function of the immune system, the release of hormones and controlling blood pressure.
When this amino acid is detected in the walls of blood vessels and the heart, it is considered to be a sign of good vascular health.
L-arginine has become popular as a supplement for bodybuilders and athletes due to its role in the creation of nitric oxide, which is a potent vasoditor.
This meaning it can increase blood flow by opening up the blood vessels.
This property is what makes arginine useful as a treatment for high blood pressure and congestive heart failure, as well as erectile dysfunction.
What Does L-Arginine do?
Arginine has many benefits, it is not only useful to people with heart conditions or blood pressure problems, but it can be very effective for bodybuilders.
Why do bodybuilders and athletes use arginine?
There are many reasons that bodybuilders and athletes commit to using arginine, let’s take a look.
L-Arginine is needed to build many of the proteins in the body, including muscles.
You can get more protein into your diet by eating protein-rich foods or drinking protein shakes.
Therefore, taking it as a supplement for muscle growth has become very common amongst bodybuilders.
There is also a belief that arginine has an effect on salt within the body, and therefore reduces bloating from water, making the muscles more clearly defined.
While there is plenty of anecdotal evidence to support these uses, the scientific community are not so sure.
One scientific study dosed eight males, aged between 18 and 33, with 5g, 9g and 13g of oral arginine on consecutive days.
Blood samples were then taken from the resting men every ten minutes for five hours.
The scientists found that there was a significant increase in growth hormone present in the blood, but that this only lasted for a short period.
The spike started about 30 minutes after taking the supplement and had reached its peak by 60 minutes after ingestion.
On the third day, when the men were given 13g of L-arginine, they all suffered ‘considerable gastrointestinal distress’.
In other words, they felt sick and had stomach cramps and diarrhoea without any corresponding increase in growth hormone.
This sounds like a win for arginine, but other studies cast doubt on whether the results are useful to bodybuilders.
Another study, set out to discover if 5g of orally administered L-arginine would raise the levels of growth hormone in young and old people, both at rest and when exercising.
In this experiment, 20 young people, aged approximately 2, and 8 older people, aged approximately 68, were given L-arginine and tested under various conditions.
The study found that oral arginine did not increase growth hormone at rest.
When combined with exercise neither the young or old group showed any improvement in growth hormone levels.
In fact, the younger group showed a lower growth hormone response than usual.
A number of other studies have had similar contradictory results.
Vasodilation and Lower Blood Pressure
Many bodybuilders take arginine for its ability to increase blood flow to the muscles.
Nitric oxide, which is made from L-arginine helps to dilate the blood vessels, increasing blood flow, and reducing blood pressure.
The relaxed blood vessels can bring a flood of nutrients and oxygen to the hardworking muscles, improving performance, preventing injury and helping recovery.
For this reason, arginine is used as a medicine for people who have congenital heart failure, angina, and other heart problems.
It would seem logical, that supplementing L-arginine will increase nitric oxide and allow the blood vessels to become flexible and relaxed during exercise.
However, studies have shown that this is not always the case.
For example, one study found that men who had taken 12g of L-arginine oral supplement per day for 7 days showed no difference in hemodynamics (the mechanisms of circulation) or brachial (upper arm) artery blood flow to men who had received a placebo.
Another study, tested 18 young men who received either 7g of arginine oral supplement or a placebo preworkout.
The results showed, no increase in blood flow due to the supplement and no reduction in the stiffness of the arteries affected by the exercises in the test.
Studies in patients suffering from heart disease and angina do show benefits from L-arginine.
But, those performed in relation to exercise on otherwise fit and healthy individuals have so far been inconclusive.
L-Arginine has been seen to boost recovery from injuries, especially bone injuries.
Combined with its ability to bolster the immune system, this supplement could help bodybuilders and athletes stay in peak condition while sticking to a tough training regime.
L-Arginine’s ability to get the blood flowing isn’t just useful for working out at the gym.
It has another bonus…
Working as an effective remedy for men suffering from erectile dysfunction.
A study published in The Journal of Sex and Marital Therapy found that the supplement works well as a treatment for erectile dysfunction.
A group of patients, aged 25 to 45, tried 1.7g of arginine plus three 40mg tablets of Pycnogenol per day for three months.
Pycnogenol is a trademark name for a supplement that comes from pine tree bark.
By the end of the trial, 80 percent experienced a significant improvement in sexual function without side effects.
How Much L-Arginine Should You Consume?
Scientific studies have looked at the effects of taking up to 20g of L-arginine per day, this is usually split into three doses.
What is the recommended dose of arginine for bodybuilding?
For bodybuilding, the accepted daily dose is anywhere up to 30g per day.
Be warned, though – taking more than 10g in one dose is likely to cause nausea, diarrhoea and stomach cramps.
To avoid side effects, it is a good idea to start off taking a smaller dose three times per day, and gradually build up.
Keeping a note of the benefits and side effects you notice will help you find the perfect dose.
Don’t forget to check any other supplements you take to see if they contain any arginine.
If they do, reduce your pure arginine dose to compensate.
When Should You Take L-arginine for Bodybuilding?
Bodybuilders usually take L-arginine before and after a workout.
The boost in growth hormone begins about 30 minutes after taking arginine, and peaks at about 60 minutes after ingestion.
This makes a preworkout dose likely to boost performance while you train.
Taking the supplement again after a workout gets the product into your body when you most need it for recovery.
Foods That Contain L-arginine
L-arginine can be found naturally in many foods.
Animal sources include dairy, pork, poultry, beef, game such as pheasant, snails, and seafood such as lobster, shrimp, and fish.
Vegetarians and vegans can get arginine from whole wheat, granola, raisins, oats, nuts, seeds (such as pumpkin, sesame, and sunflower), chickpeas and buckwheat.
Its good to know that arginine is also present in chocolate.
Although most healthy adults will get enough L-Arginine from their diet it may be beneficial for bodybuilders and athletes to supplement.
Side Effects of L-Arginine
Most studies of L-Arginine have looked at doses of up to 20g per day for periods of up to three months.
This dose is usually split into three smaller doses throughout the day.
Are there side effects to taking arginine?
The most common side effect of l-arginine occurs if you take 10g or more in any one dose.
Most people who try this suffer from stomach cramps, sickness, and diarrhoea.
Taking the supplement on an empty stomach will make sickness more likely, but keeping the dose below 10g should help you avoid this unpleasant side effect.
There are a couple of studies, which suggest that taking the supplement over a period of six months or more may cause it to become less effective, and could possibly lower prolactin levels.
Scientists have noted that there is no evidence to suggest L-arginine is safe for everyone long term.
People with kidney or liver problems should not take arginine supplements, without asking their doctor.
Usually, the body will flush away any excess amino acids, but build-up can occur if the kidneys or liver are not functioning well.
This can lead to secondary problems such as high potassium, and an irregular heartbeat.
If you have low blood pressure or have recently had a heart attack, then this supplement could cause problems because of its ability to lower blood pressure further.
Arginine has also been known to interfere with blood pressure medication.
These effects can also be a problem during surgery, so do not take L-arginine if you have recently had an operation, or are going to have an operation soon.
Finally, arginine can cause an allergic reaction.
It can also bring on asthma attacks, so if you have allergies or asthma, take care if you decide to try L-Arginine.
We recommend consulting a doctor if you are planning to supplement arginine.
Do You Need to Cycle L-Arginine?
There is no clear evidence on whether or not to cycle arginine.
There are claims that because it is made naturally in the body, there is no way of overdosing.
But, there are a couple of studies which suggest cycling is a good idea.
One study showed decreased effects from arginine after six months, implying that over time the body builds up a tolerance to the substance.
This could mean that you stop seeing benefits after prolonged use.
Another study showed that L-Arginine may affect prolactin levels.
Do you suggest cycling L-Arginine?
Arginine stays in the body for up to three months, so cycling two months on then two months off should give the benefits with less chance of any tolerance developing.