ZMA vs Casein: Which Is Better for Nighttime Recovery?

Recently, I’ve received a few questions from readers asking whether I prefer ZMA (a specific blend of magnesium and zinc) or casein for athletic recovery at night. This is an especially interesting question to me, because the two supplements vary so much; the question itself is a little bit misleading, as ZMA is a mineral blend while casein is a slow-digesting protein. Basically, there’s not reason to think they need to be mutually exclusive!

I’m a big fan of ZMA (I really like True Athlete’s version, which adds the calming amino acid l-theanine to the blend). It’s a blend of specific forms of magnesium, zinc, and vitamin B6 that promote deep, restful sleep. Though versions of the formulation are made by several different brands, the blend was originally developed because it may enhance athletic recovery after exercise — though that’s a controversial may, and studies are mixed. ZMA is much more widely accepted as an effective sleep aid — again, my experience backs this — and better sleep itself is an important recovery-enhancing tool.

Casein, on the other hand, is a protein derived from milk, similar to whey protein. It generally digests slower than whey protein, making it an effective tool in promoting protein synthesis (aka the process that builds muscles) while we sleep. Many athletes drink a casein-based shake sometime before bed to give the body a ready supply of protein for muscles while they sleep. Casein generally blends to a thicker, creamier shake than whey protein.

When I was a college athlete (and occasionally still), I will drink casein protein at night or before bed. My go-to brand for years has been Optimum Nutrition’s casein, a popular version for athletes that doesn’t feature a long or confusing list of ingredients. Pretty much every athlete I know has tried and enjoyed this casein protein.

ZMA may not be the best combo for sleep, however, as there’s some research to indicate that when consumed together, zinc and calcium reduce each other’s absorption in the gut (though the effect seems relatively small). Personally, I don’t like taking protein shakes immediately before bed, and I’ll often take one in the evening as a last meal a few hours before I go to sleep. Then I’ll take ZMA 30-60 minutes before bed. This ordering seems to work well for me to promote restful sleep and recovery, though individual results may vary!


Having written hundreds of articles on, Caitlyn knows what she's talking about when it comes to getting the best night's sleep. When not sleeping, reading about sleep, or writing about sleep, you can usually find her at the gym. Want to get in touch? The best way is to leave a comment on one of her articles.