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What is b-silkTM protein?

While most consumers are aware that traditional silk (derived from silkworms) has long been used to make luxurious textiles, the use of silk in biomedical engineering and skin regeneration is perhaps lesser-known. Naturally, after unlocking our premier biomaterial, Microsilk™, the team of material scientists at Bolt Threads were eager to explore the potential benefits of using our vegan spider silk proteins in skincare applications. A small group of Bolt scientists set out to create and test exploratory formulations and were happily encouraged by the positive feedback we received from our multitude of studies and clinical trials. 

From these early formulations, we knew that we discovered something special. B-silk™ protein offered the same impressive biocompatibility as traditional silk proteins and showed promise to surpass traditional silk as a barrier defense for skin and hair. We named our proprietary silk “b-silk™ protein” and embarked on a journey to disrupt the skincare industry with this vegan, biodegradable, and efficacious ingredient.

B-silk™ protein was inspired by the properties of spider silk. Spider silk has a unique molecular makeup that makes it stronger and stretchier than the commonly used silkworm silk. Like natural silk proteins, b-silk™ protein is a high molecular weight structural protein that complements the vital functions of your skin and reinforces its extracellular matrix (a.k.a. collagen and elastin, the proteins that break down as we age).

What makes b-silk™ protein so well-suited for beauty products? It comes down to our patented process. When traditional silk proteins are used in other skincare products, they are usually fragmented into smaller pieces using a process called molecular hydrolysis. This process breaks down a bigger molecule (polymer) into many smaller molecules (monomers) by severing the bonds that hold monomers together. Hydrolyzed silk proteins are highly processed and degraded, which compromises their valuable properties and effects.

B-silk™ protein, on the other hand, is not hydrolyzed. Through rigorous development, we came up with a production process that keeps the proteins intact. How do we do it? We produce them in our labs through fermentation. Using yeast, water, sugar, and salt, we create large quantities of the proteins, all with an intact molecular structure that delivers more benefits, for better results.

So what were the results from our clinical trials? In a third-party, quantitative clinical trial comparing a skincare moisturizer formulated with and without b-silk™ protein, we found that b-silk™ protein significantly improved skin’s firmness, elasticity, the appearance of fine lines and wrinkles, and overall skin health. In fact, 100% of the clinical trial subjects saw an improvement in these metrics after only 8 weeks of use, as determined by expert grading.  We call that, science for the win!  

We’re not done yet. While b-silk™ protein products are currently available for purchase in premium, clean-beauty products from partners like Vegamour, Bolt scientists are busy collaborating on the protein’s next chapter. We recently announced a partnership with Ginkgo Bioworks who specialize in strain engineering. This new partnership will leverage Ginkgo’s expert engineering capabilities to improve the production efficiency of this incredible ingredient to make it more widely available and potentially unlock more applications for the clean beauty and personal care industries. That means more ways to benefit from the benefits of b-silk™ protein. 

To learn more about b-silk™ protein, visit

Eager to try our next generation b-silk™ protein formulas for yourself? Sign up for Beebe Labs, Bolt’s beta testing endeavor for beauty that delivers safe, at-home test kits in exchange for honest feedback.


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