Nothing’s better than a glass of cold milk, especially when chocolate chip cookies are included in the mix. And while humans have been milking cows , soy milk was only developed in the and has since become an alternative to the traditional stuff. But what’s the better option?

Meet the Competitors

Skim milk and soy milk may look pretty similar, but their content can vary quite a bit. is a better source of calcium, vitamin A, and vitamin C, while wins in the vitamin D and iron categories. Calorie content varies between brands, but skim milk generaly has about 20 more calories per cup. And while skim milk has traces of fat (around 0.4 grams), soy milk is naturally fat-free. They do have one thing in common, though— and it’s good news for those skinny jeans— studies suggest the calcium in both milks can help accelerate weight loss . Lukaszuk, J.M., Luebbers, P., Gordon, B.A. School of Family, Consumer, and Nutrition Sciences, northern Illinois University. Journal of the American Dietetic Association, 2007 Oct;107(10):1811-4. . Zemel, M.B., Thompson, W., Milstead, A., et al. University of Tennessee, Knoxville, Tennessee 37996-1920. Obesity research, 2004 Apr;12(4):582-90..

Cow’s milk and soy milk also pack different punches when it comes to protein. Moo Juice contains both , both great for . While whey protein is quickly absorbed into the bloodstream, casein is digested more slowly and provides the body with protein for a longer period of time, together providing a mean one-two protein punch . Boirie, Y., Dangin, M., Gachon, P., et al. Laboratoire de Nutrition Humaine, Université Clermont Auvergne, Centre de Recherche en Nutrition Humaine. Proceedings of the National Academy of Sciences of the United States of America. 1997 Dec 23;94(26):14930-5.. Soy milk, however, contains only , since it’s made by . Soy protein has been found to reduce LDL cholesterol (the “bad” kind) and raise HDL cholesterol (the “good” kind) . Wofford, M.R., Rebholz, C.M., Reynolds, K., et al. Department of Medicine, University of Mississippi Medical Center, Jackson, MS, USA. European journal of clinical nutrition, 2011 Sep 28. Doi: 10.1038/ejcn.2011.168.. Trying to build muscle? Beware— one study suggested that milk-based proteins promote greater muscle growth than soy-based proteins when consumed after resistance exercise . Wilkinson, S.B., Tarnopolsky, M.A., Macdonald, M.J., et al. Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Canada. The American journal of clinical nutrition, 2007 Apr;85(4):1031-40..

While both milks contain essential vitamins and minerals and can help with weight-loss and muscle-gain, each has its own set of potential pitfalls. Soy milk (plant-produced estrogens), which act similarly to estrogen and may decrease fertility in men . Chavarro, J.E., Toth, T.L., Sadio, S.M., et al. Human Reproduction, 2008 Nov;23(11):2584-90. Epub 2008 Jul 23.. But good news, guys— there’s no need to say “soy long” to soy milk. Men can consume soy in moderation without worrying about estrogen overload— just don’t consume more than 3 quarts of soy milk per day . Nagata, C., Takatsuka, N., Shimizu, H., et al. Department of Public Health, Gifu University School of Medicine, Japan. Cancer Epidemiology, Biomarkers and Prevention. 2001 Mar; 10(3):179-84.. Of course, there’s also concern over hormones in regular milk, specifically bovine growth hormone (rBGH). Although rBGH , there’s no definitive proof. Still worried? Try organic or hormone-free milk instead of regular, to avoid ingesting the rBGH hormone.

The Decision

So is it time to say bye-bye to the moo-moo, or see-ya-later to the soy? Good news— this battle is a toss up! Both options have their benefits— and their dangers— but are fine when consumed in moderation. For those who are lactose intolerant, soy milk can be a saving grace. But if not, don’t forget that a glass of dairy packs more protein and calcium than the soy stuff. In the end, it all comes down to the tongue— and perhaps which milk ‘stache looks better.