Proline: Amino Acids And Anti-Aging.



What Is Proline?

Proline is an amino acid that is primarily used in anti-aging skincare products because of its ability to help improve skin elasticity, increase collagen production, and promote skin repair and regeneration.

Proline is an amino acid that is used as a building block in the production of proteins. Amino acids are the main component of proteins, think of them as the units that are combined in many different ways to form proteins that the body can use to maintain healthy functioning. Proteins are used in a variety of ways in the body, not just in muscles as we are most familiar with. Proteins are used as a signalling molecule, telling the body what to do, they are involved in the immune system, skin health, the list goes on. 

There are 20 amino acids, some are considered to be essential and some are non-essential. Proline is a non-essential amino acid, which means that the human body can synthesize it from the non-essential amino acid L-glutamate. Essential amino acids, like lysine are amino acids that we need to get from our diet as they can’t be synethiszed in the body. 

 In addition to use in skin care products, proline is often used in pharmaceuticals and biotechnological applications because it functions as an osmoprotectant, which means it can protect other drugs from degradation from oxidative stress.


the good: Proline may help to support the skin’s natural healthy functioning and may be useful in reducing teh visible signs of aging.

the not so good: Proline is a natural component of the body. It isn’t considered to be irritating or sensitizing.

Who is it for? All skin types except those that have an identified allergy to it.

Synergetic ingredients: Works well with most ingredients

Keep an eye on: Nothing to keep an eye on here.

What Are The Benefits Of Proline?

In cosmetics and personal care products, proline primarily functions as an anti-aging ingredient because of its ability to improve skin elasticity, increase collagen production, and promote skin repair and regeneration.

After topical application, proline and other amino acids can effectively penetrate the skin because they have an average molecular weight of 110 Daltons. This is well under the 500 Dalton rule, which states that compounds above 500 Daltons have a much harder time penetrating into the skin.

Proline is often used in anti-aging skin care products because of its ability to reduce the appearance of fine lines and wrinkles. One factor that contributes to the formation of fine lines and wrinkles is decreased flexibility or elasticity of the stratum corneum (the uppermost layer of the skin). According to a publication in the European Journal of Dermatology, the elasticity of the stratum corneum has been shown to be regulated, at least in part, by the amounts and types of amino acids. This publication also reports that a study conducted on 126 Japanese female subjects found that topical application 1-carbamimidoyl-L-proline, a derivative of proline, significantly improved the appearance of crow’s feet lines. This suggests that proline and its derivatives are promising and useful ingredients for the improvement of wrinkles through the ability to enhance the elasticity of the stratum corneum.

Another major factor that contributes to the formation of lines and wrinkles is a decrease in the amount of collagen in the skin. The body produces less and less collagen with age. In fact, after the age of 20, a person produces about 1 percent less collagen in the skin each year. Moreover, environmental free radicals can degrade collagen proteins. The result is skin that becomes thinner and more fragile with age. Using ingredients that stimulate collagen production, such as proline, can help to maintain skin firmness and elasticity. Specifically, proline is a substrate that is necessary for collagen synthesis. Collagen has a triple helix structure composed of proline, hydroxyproline, and glycine.

Of all the amino acids that form collagen, proline’s effects on promoting skin health has probably been the most well-researched. It is well known that proline can help to repair damaged skin and promote wound healing due to its ability to support collagen synthesis. Collagen is necessary for wounds to heal properly because it gives structure and strength to the skin.

Is Proline Vegan?

Proline is a tricky ingredient to produce as a vegan product. This is because it is found in collagen, joints and tissues. This means that most forms of proline are derived from animal-based sources. However, it can be made synethically or used in the form hydroxyproline, which can be derived from plant based sources and converted to proline in the body. 

Whether your proline-containing product is vegan or not will depend on the source that the brand is using. It is best to check whether the brand specifies that it uses plant-based proline or not. 

Is Proline Safe?

The safety of proline and the other alpha-amino acids has been assessed by the Cosmetic Ingredient Review Expert Panel. The Cosmetic Ingredient Review Expert Panel is a group responsible for the independent evaluation of the safety and efficacy of skincare and cosmetic products. 

Due to the normal presence of proline in the body and its use as a direct food additive approved by the US Food And Drug Administration, the Expert Panel focused their review on dermal irritation and sensitization data. 

Dermal data on products containing proline indicated that this ingredient is not a dermal irritant or sensitizer. Thus, the Expert Panel concluded that proline and the other alpha amino acids were safe as used in cosmetics and skincare products.

Albaugh VL, Mukherjee K, Barbul A. Proline Precursors and Collagen Synthesis: Biochemical Challenges of Nutrient Supplementation and Wound Healing. J Nutr. 2017;147(11):2011-2017. 
Karna E, Szoka L, Huynh TYL, Palka JA. Proline-dependent regulation of collagen metabolism. Cell Mol Life Sci. 2020;77(10):1911-1918. 



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