Marine collagen is all the rage in anti-aging. What does that mean for fish?

It may come as a scoop of white powder to add to a latte or smoothie, promising to help achy joints and sagging skin.

Or, as an ingredient in face masks and moisturizers, claiming to offer a youthful glow.

It's marine collagen, a buzzword in beauty and supplement circles, often derived from fish skin, scales and bones, or other animals like sponges and sea cucumbers, depending on the product. 

The global market for marine collagen is already estimated at more than $1 billion US and growing, driven by demand to look and feel younger.

It's promoted as an alternative to traditional sources of collagen supplements, derived from land animals like cows and pigs, which some avoid for religious or other reasons.

Many marine collagen products also market themselves as natural or eco-friendly, featuring images of waves and fish and references to "cold, clean" ocean waters.

But with overfishing and climate change already threatening global ocean wildlife, is this a sustainable place to turn for anti-aging hope?

It depends, according to those watching this emerging conservation issue, on where the collagen is coming from — something that might not be clear at all when you pick up the product.

"With these marine collagen products, shoppers are buying a black box of marine ingredients," said Kelly Roebuck, sustainable seafood campaigner with the Canadian marine conservation group Living Oceans Society, in an email to CBC News.

Our bodies naturally make collagen, which provides elasticity and strength to our skin, tendons, bones and other tissues. We make less as we age.

But it's widely found in the animal kingdom — even in the 68-million-year-old bone of a T. rex — so people have turned to collagen supplements derived from other creatures.

Health Canada licenses more than 2,000 natural health products containing hydrolyzed collagen as a medicinal ingredient, and more than 1,000 with collagen from marine sources. 

Bovine collagen, from cows, has led that industry. But last year, an investigation by the Bureau of Investigative Journalism, The Guardian and others linked cattle ranches producing collagen, leather and beef to tropical rainforest loss in the Brazilian Amazon.

The investigation traced the collagen supply chain to major companies, including the Nestle-owned brand Vital Proteins promoted by Jennifer Aniston. (Nestle has said it is taking steps to ensure products are deforestation-free by 2025.)