Pea Peptides: What are their effects on hair, eyelashes, and eyebrows?

Pea peptides are hydrolysed pea proteins (oligopeptides = short chain peptides) composed of 22 amino acids (750 Da), including glutamic acid, aspartic acid, arginine, lysine and leucine, all of which are believed to be essential for hair health. Indeed, pea peptides have recently been highlighted in numerous hair care products.

According to some sources, pea peptides would serve as a multifunctional active ingredient when used in hair care formulations. In other words, they would offer moisturising, antioxidant, smoothing, and volumising benefits for the hair.

• When applied to the scalp, pea peptides are believed to stimulate and strengthen follicular stem cells, thereby promoting hair growth and repair, and preventing hair loss.

• It has also been proven that they would smooth and thicken the hair shaft, thus instantly adding volume to hair strands with just 2% of pea peptides.

• This ingredient would also enhance the hair's ability toretain moisture by forming a film on the surface, which would reduce dehydration.

• Thanks to its high concentration of lysine found in pea protein hydrolysate, it would minimise the damage to hair follicles caused by free radicals due to its antioxidant benefits, particularly against oxidative stress.

• Pea peptides also reportedly prevent cracks and damage to the cuticles, such as those caused by heat appliances (hair dryers, straighteners, etc.), by forming a protective structure through the binding of amino acids.

But have these facts been scientifically proven?

The studies found focus particularly on the effects of pea shoot extract, a rich source of biotin, L-arginine and isoflavones, as well as on the green pea peptides themselves.

• A cosmetic study has established that the application of a 4% pea shoot extract, formulated in a gel base, to a defined area of the scalp (n = 20 volunteers; twice daily for three months) has enabled toincrease hair density, by improving the ratio between hairs in the growth phase (anagen) and in the resting phase (telogen). The hair gel containing the pea extract thus reduced the number of telogen hairs (-28.3%) and increased the number of anagen hairs (+7.9%). As a result, the hair loss observed in subjects at the start of the study was normalised after three months of application.

• In 2020, a pilot study demonstrated that dietary supplements (100 mg) and topical products (2%) containing pea sprout extract could potentially reduce hair loss and promote hair growth in individuals experiencing mild to moderate hair loss (≥ 100 hairs lost per day), without any side effects.

Furthermore, the results of another clinical study (n = 10; twice daily for two weeks) revealed that the topical application of 2% pea extract on the scalp modulated the expression of the genes FGF7 and noggin, two signalling compounds synthesised in the cells of the dermal papilla and involved in inducing a new phase of hair growth.

More specifically, the overexpression of noggin would result in a shortening of the resting phase by inhibiting the activity of Bone Morphogenetic Protein 4 (BMP4), which would have the effect of "braking" the transition between the telogen and anagen phases, thus having a stimulating effect on hair growth. FGF7, on the other hand, would act as a signalling factor that would command the proliferation of hair germ cells, thereby initiating a new hair cycle.

Although these results are very encouraging, placebo-controlled studies, with a larger number of participants and an extended observation period, are necessary to validate the effectiveness of pea sprout extract in regulating the cyclical process of hair growth. And most importantly, what about the specific effects of pea peptides on hair growth? In addition to these benefits, pea extract has also shown anti-inflammatory and antioxidant properties which may impact the hair follicle cycle.

The pea peptides (INCI: Pisum Sativum (Pea) Peptide) used in our various treatments correspond to hydrolysed pea proteins, obtained through bio-fermentation with the probiotic bacteria, Lactobacillus bulgaricus.