Written by Carina Fabia
Last updated on: Oct 21, 2022
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Hemp protein is not a complete protein. Although it contains all 9 essential amino acids, it has low levels of the essential amino acid lysine. It is also relatively low in leucine, this means hemp protein powder is not an ideal supplement to support muscle growth. However, the health benefits of hemp still make it very attractive.
Hemp protein powder is derived from hemp seeds. It is high in protein and fiber; and contains essential fatty acids (healthy fats) and oxidants which provide numerous health benefits. Hemp protein powders have grown in popularity amongst those who are looking to increase their protein intake using a plant protein source which is environmentally sustainable (1). Hemp based protein supplements are available in powder, bar and capsule form.
Due to the increased popularity of hemp protein powder, many have grown curious as to whether it can assist them improve the quality of their life and achieve their goals. One of the most common questions about hemp is whether or not it can be considered a complete protein. The simple answer to this question is no hemp is not a complete protein. However, it is not far off and does contain each of the essential amino acids. Let's first look at what criteria a protein source must fulfil to be considered a “complete protein”.
A complete protein is a protein which has good levels of all 9 essential amino acids (2). Your body cannot produce these amino acids, so they must be obtained through the diet.
There are 20 different amino acids. 9 of these are considered essential. And the other 11 are considered non-essential. The reason for this because these can be produced by the body.
Essential amino acids (EAA's) are vital for many bodily functions, including growth, development, immune function, and muscle repair. While the non-essential amino acids are not as vital they still play an important role in the body and are necessary for proper health.
The 9 EAA's; histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. The 11 non-essential ones are; alanine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, tyrosine, and arginine.
According to a Euphytica study published in 2004, hemp protein comprises of nutritionally significant quantities of all essential amino acids and has an amino acid profile which is comparable to soy and egg white protein (3).
However, a more recent study states hemp protein has insufficient levels of leucine and lysine (4). This is what makes it not possible to describe hemp as a complete protein source.
Hemp has low levels of lysine. To compensate for hemp's low levels of lysine it can be obtained though dietary sources such as meat, fish, dairy, and beans (5). This critical amino acid plays an important role in the proper growth and development of the human body. It is needed for the production of enzymes involved for digestion and metabolism. The production of hormones such as testosterone and estrogen. It is also involved in the absorption of calcium, which is important for strong bones and teeth.
Most people get sufficient levels of lysine from dietary source, but some people may need to take additional supplementation. Lysine supplements are available in both pill and powder form (6).
Hemp does not have the best leucine levels. Although it is considered to have sufficient levels, it falls short of the the levels produce by other protein sources such as whey protein and pea protein. This makes hemp not as attractive a supplement for the development of muscle growth and assisting with muscle recovery. Leucine is one of the branched chain amino acids (BCAA's). It plays a major role in regulating muscle protein synthesis. After workout, the body will synthesise protein at a slower rate than the breakdown of protein. This means there is a negative balance in muscle protein. To recover this balance and trigger muscle protein synthesis the body needs to increase the levels of leucine in the muscle tissue (7). This is why good leucine levels are important to athletes, bodybuilders and those serious about fitness. By increasing leucine intake, post-exercise muscle protein synthesis can be stimulated.
Hemp protein cannot be considered a complete protein due to having low levels of leucine. It is also arguable it has questionable levels of leucine. However, it does contains all 20 amino acids. Hemp is an excellent source of plant-based protein, however if you want a supplement to support athletic performance or muscle growth there are better alternatives. Namely whey protein or pea protein (hemp/ pea protein blends are growing in popularity which allows the best of both worlds, good levels of all nine essential amino acids with all of health benefits of hemp).