Croda claims that where ProSina differs from most other keratins is in its unusually high cystine content in the active S-sulpho form. The high proportion of these groups enables Prosina to cross-link with the keratin in nails, resulting in an increase in the integrity and cohesion of the nail plate.
Meanwhile, the natural moisturising properties conferred by the low molecular weight peptides is also said to improve skin hydration, elasticity and barrier function, and create visible improvements in skin texture.
"The ingredient was launched this week on to the European market and this is expected to be expanded into the global market in the coming months," Croda Personal Care marketing manager Karen Ryan said.
The ingredient addresses the problem many women face when hands and nails experience repeated exposure to the drying effects of detergents, solvents, extremes of temperature and sunlight. This can cause the skin to dehydrate and lose its natural strength and elasticity, and result in nails becoming brittle and prone to breakage.
"There are few products on the market with strong claims for the improvement of nail strength as well as improving the condition of skin. We have conducted a number of skin and nail studies with ProSina which show that this novel ingredient provides conditioning and protection benefits for both hands and nails,"commented a Croda spokesperson.
In one study the effects of ProSina on nail integrity were demonstrated using a protein solubility test. Croda says the results show that nails treated with a cream containing 3 per cent ProSina reduced the solubility of proteins within the nail by 62 per cent compared to nails treated with the base cream. This, the company claims, demonstrates that ProSina helps to improve the integrity and cohesion of the nails.
The company also said further testing, involving scanning electron microscopy of the free lateral edges and tips of nail plates, offered further evidence of the added integrity provided by the new ingredient.
As well as being effective on nails, the company's claims are also supported by substantiation work on hand skin. Tests have shown that the ingredient increases the hydration and elasticity of dry skin compared with a control.
"Where this ingredient is unique is that if offers proven nail and skincare data," Ryan added. "There are many hand cream products on the market that have keratin-based ingredients, but few that can be backed up with such robust data. However, this is the way that the hand cream market is likely to go, with new ingredients have to prove their efficacity."
For hands repeatedly exposed to detergents that can irritate and damage the skin, a surfactant study demonstrated that ProSina enabled the skin to recover more quickly from exposure to sodium lauryl sulphate (SLS) compared with a control cream, the company said.
Croda says that the ingredient has a wide pH tolerance and is easily incorporated into cosmetic formulations, making it an ideal target applications for hand and nail creams, barrier preparations, and foot treatments.
Although still a relatively small sector, the global hand cream market is nevertheless showing signs of continued strong growth. Currently valued by Croda at £852 million (€1.24bn), the market has had a compound annual growth rate of 4.6 per cent from 1997 to 2004.