Abstract: The non-therapeutic, cosmetic, oral use of a composition as an active ingredient for whitening and/or lightening the skin and/or depigmenting the skin, in particular for reducing the size of brown spots, including at least cystine and glutathione in a cystine/glutathione ratio ranging from 1.5 to 4, the composition advantageously further comprising glycine and/or glutamine Preferably, the composition also includes at least one component selected from the group formed by zinc or one of its salts, copper or one of its salts, selenium or one of its salts, vitamins B, in particular B3, B5, B6 and/or B8, vitamin E, melon juice extracts, horsetail extracts and mixtures of these components.

Abstract: A keratin hydrolysate including at least 88% by weight of free amino acids relative to the total weight of the amino acids of the hydrolysate and including a content of free tyrosine between 2% and 4% by weight relative to the total weight of the free amino acids of the hydrolysate. Also, a method for preparing the hydrolysate including the following steps: acid hydrolysis, a pH adjustment and a desalination. Also, the use of the hydrolysate for pet food, aquaculture food, and plant biostimulants.

Abstract: A keratin hydrolysate including at least 94% by weight of free amino acids relative to the total weight of the amino acids of the hydrolysate. The keratin hydrolysate includes at least 93% of free valine relative to the total weight of valine in the hydrolysate, at least 90% free isoleucine relative to the total weight of isoleucine in the hydrolysate, and at least 95% of free leucine relative to the total weight of leucine in the hydrolysate. A method for producing the keratin hydrolysate, a composition comprising the hydrolysate and an animal feed containing the hydrolysate are also disclosed.

Abstract: The non-therapeutic, cosmetic, oral use of a composition as an active ingredient for whitening and/or lightening the skin and/or depigmenting the skin, in particular for reducing the size of brown spots, including at least cystine and glutathione in a cystine/glutathione ratio ranging from 1.5 to 4, the composition advantageously further comprising glycine and/or glutamine Preferably, the composition also includes at least one component selected from the group formed by zinc or one of its salts, copper or one of its salts, selenium or one of its salts, vitamins B, in particular B3, B5, B6 and/or B8, vitamin E, melon juice extracts, horsetail extracts and mixtures of these components.

Abstract: A hydrolysate including at least 94%, preferably at least 96%, more preferably 100% by weight of free amino acids relative to the total weight of the amino acids of the hydrolysate, the hydrolysate including at least the following amino acids: at least 93%, preferably at least 95%, of valine in free form by weight relative to the total weight of valine in the hydrolysate, at least 90%, preferably at least 95%, of isoleucine in free form by weight relative to the total weight of isoleucine in the hydrolysate, at least 95%, preferably 100%, of leucine in free form by weight relative to the total weight of leucine in the hydrolysate. Also, a method for preparing the hydrolysate and also a starting material and a complete feed for animal feed containing the hydrolysate.