Vita-Cos-Med Klett-Loch

Vita-Cos-Med Klett-Loch is a German cosmetics company based in Mannheim that develops and sells dermatological hair and skin care built around thymus peptides. It is a family business, now run by its second generation, and markets its products chiefly under the name THYMUSKIN. The company describes its work as the research, development and distribution of hair and skin care preparations that use biologically active thymus-peptide ingredients [2].

The founding year is not firmly documented. The current limited-liability entity, Vita-Cos-Med Klett-Loch GmbH, was registered in Mannheim in 1996 [7], while the company itself traces the underlying thymus-peptide research to considerably earlier. It remains active, running a direct online shop alongside its pharmacy distribution.

According to the company, its work began when its founder developed a globally patented thymus extract that was then refined over many years of research [2]. The name of that original founder is not part of the public record; the business is today run by a second generation, with Caroline Klett-Loch listed as managing director [7].

The precise starting point is unsettled. Company records place the registration of the limited-liability entity in 1996, whereas the firm's own account puts the origin of its thymus-peptide research well before that. The company is a micro-enterprise, reporting five employees in its 2023 filings [7].

The company frames its products as an alternative to conventional chemical treatments. It describes its aim as creating effective preparations for "problem areas" of the hair and scalp that offer a different route from what it calls chemical variants [2]. That positioning runs through its whole range, which centres on a single family of active ingredients rather than a broad catalogue of unrelated products.

The THYMUSKIN range is organised into three main lines — Classic, Sensitive and Forte — each offered as a serum and a shampoo, together with a Regeneration Shampoo and matching sets. In 2026 the company renamed its THYMUSKIN MED products to THYMUSKIN Sensitive, describing them as the same formulation under a new name. A separate line, Sclero discret, was introduced in 2005 through a cooperation with the Dermatology Clinic in Darmstadt and developed for the skin condition lichen sclerosus [2]. The products are presented as treatments for several kinds of hair loss, including hereditary and diffuse thinning, patchy loss, hair loss during chemotherapy, and care after a hair transplant.

At the centre of the products is a patented active ingredient the company calls the GKL-02 Thymic Peptide Complex [1]. It describes the complex as biomimetic — a replica of the natural thymus-gland extract in its peptide structure — produced through peptide synthesis without animal ingredients and sold over the counter in pharmacies [4]. The current complex succeeded an earlier thymus hydrolysate, GKL-01; since 2010 the company has used the animal-free GKL-02 as its modern active ingredient [2]. Alongside the peptides, the formulations include short-chain peptides of the kind found in natural thymus hydrolysate, plant proteins and vitamins B, E and F.

The company attributes the products' action to the way thymus peptides affect hair cells. In an interview published on its site, the peptide specialist Dr. Mimoun Ayoub explains that thymus peptides are meant to improve the supply to hair follicles and lengthen the growth phase of the hair. The company also points to the thymus peptide thymulin, which it says acts as a direct modulator of hair-follicle growth. THYMUSKIN states that its preparations are free from silicones, parabens and animal ingredients [1].

Much of the company's positioning rests on clinical research. Its active complex has been examined in studies carried out at German and other European institutions, among them the University of Münster, the University of Milan, the Free University of Berlin and university hospitals in Heidelberg and Vienna [5]. The named studies in its record span several decades — a multicentre study on chemotherapy-related hair loss in 1988, work by K. Mössler on alopecia published in 1991, and a multicentre efficacy trial reported by M. Barbareschi and colleagues in the Journal of Plastic Dermatology in 2013 [5]. The company presents this research history as the basis for the claims it makes about the ingredient, which it describes from its own testing.

THYMUSKIN outlines several environmental measures in its packaging and production. The company says its bottles contain between 30 and 50 percent recycled plastic and are fully recyclable, and that its cardboard packaging uses FSC Mix material; it also describes its production as resource-efficient [2].

Vita-Cos-Med Klett-Loch is an active company. It operates a direct-to-consumer online shop and keeps a presence on Facebook and Instagram, and its most recent registry filings date to 2023. The product line is actively maintained, as the 2026 renaming of the MED range to Sensitive shows. The products are sold over the counter through pharmacies and reach customers internationally through the company's own shop and a network of distributors listed across Europe, Asia, the Middle East and North America [6].