Who needs the sun? Many Silicon Valley startups pride themselves on long, grueling work hours, toiling from the crack of dawn until late into the night. But that work pride has a toll — they likely suffer from a serious lack of vitamin D.

Most U.S. office workers do these days and Nootrobox co-founder Geoff Woo says that’s affecting our brains.

Vitamin D plays an important role in calcium absorption, boosts your immune system and may protect against certain forms of cancer, type 1 diabetes, and multiple sclerosis. Without enough of it, you may experience a sort of brain fog and lowered cognitive function.

Startups like Nootrobox, Nootroo and other “smart drug” subscription services started popping up in the last year to help Silicon Valley workers boost brain power. They join a growing cottage industry of products in the biohacking movement, like Bulletproof coffee, smart cocoa and even small doses of psilocybin (hallucinogenic mushrooms) aiming to give those in startup land a performance-enhancing leg up.

Woo and his co-founder Michael Brandt initially released a “stack” of chemically enhanced pills promising to help people wake up, focus and sleep better. The startup pulled in Andreessen Horowitz, Yahoo’s Marissa Mayer and Zynga founder Mark Pincus as investors to help launch the subscription service in 2015. Nootrobox later released “Go Cubes,” chewable coffee cubes, which offer an “evened-out” caffeine kick.

Now Woo wants to add vitamin D (which is actually a hormone, not a vitamin) to boost brain power, too.

Nootrobox is launching KADO-3, a fish oil and krill oil blend with a specifically high ratio of DHA (docosahexaenoic acid) to EPA (eicosapentaenoic acid) to provide a premium vitamin D designed for cognitive function.

Though recommendations differ on the amount we need in our daily diet, the interest in the vitamin goes all the way to the White House. First Lady Michelle Obama recently convinced the FDA to include vitamin D levels on the new food labels.

But pop in at any local nutrition store and there’s plenty of vitamin D sitting on the shelves. Woo says what’s in those bottles is different from what he’s offering.

“Typical Omega-3 blends have a high ratio of EPA to DHA. EPA is associated with cardiovascular benefits while DHA is associated with brain benefits. Whereas Nootrobox ramps up the ratio of DHA to EPA,” says Woo.

The blend also adds Astaxanthin, a neuroprotective that could help manage the risks of geriatric conditions, and vitamin K2, which also has been shown to benefit both the cardiovascular system and the brain.

Woo also revealed the company plans to eventually create a personalized blend based on someone’s DNA to enhance their overall function and Nootrobox will likely partner with one of the larger genetic testing companies to provide such a product, but he said he is not in talks with anyone and that offering won’t be available anytime soon.