UPDATED: Video added after the break.

There are women’s specific bikes, clothes and components, but few endurance nutrition products aimed at the fairer sex.

So why would OSMO create pre-, during and post drink mixes for women? Because, as they put it, “women are not small men.” Thankfully true, but what do they need to fuel their bodies that men don’t? Here’s the breakdown, from OSMO’s co-creator Dr. Stacy Sims:

“Women have a physiology that’s different than men, and until recently most of the data collected were conducted largely on men. But women have a menstrual cycle that impedes generalizing what’s good for a man must be good for a woman. (Thus, research has lagged because) women have been deemed ‘too difficult’ to be included in research because of these hormone fluctuations.

“How do estrogen and progesterone affect a female athlete? For starters, women have an altered energy metabolism during exercise which completely impacts how we recover. Our recovery window is smaller and we have a predisposition to become
over trained if we do too much intensity at different parts of our periods. During the menstrual cycle, we have two hormone phases: high and low. During the low hormone phase, our carbohydrate metabolism and recovery are closer to men’s and we are
able to complete high intensity workouts4-7. However during the high hormone phase, estrogen reduces the availability of carbohydrate and increases the amount of fat used for fuel; thus we have problems hitting intensities. Elevated progesterone increases our core temperature by ~0.5ºC, increases total body sodium losses, and increases muscle breakdown (and at the same time, reduces the body’s ability to synthesize muscle).

“If this wasn’t enough, the combination of elevated estrogen and progesterone drops our available plasma volume by ~8%; and with concurrent shifts in baseline thresholds, makes us more predisposed to hyponatremia. Finally, the recovery window for men and women is different. Women have 30 minutes for acute recovery and only 3 hours to eat a balanced meal for glycogen recovery.

“To address these physiological realities I have developed and tested three formulas that Osmo is bringing to market now. These formulas are based on research that I and other scientists have published in peer reviewed journals. It is my sincere hope that multitudes of female athletes will use these products and experience how much better they feel and perform when they get the nutrition that matches their physiology.”


So, here’s the breakdown of products, with differences from originals noted:

PRELOAD HYDRATION: Adds branched chain amino acids that work with the sodium to expand total body water. This increases the total number of amino acids circulating, which can dampen the effect of progesterone. Flavor is Pineapple Margarita. $24.99 for 20 servings.

ACTIVE HYDRATION: Increased sodium content to offset greater sodium losses in women, which helps maintain plasma volume. Flavor is Mango. $19.99 for 40 servings.

ACTUE RECOVERY: Same 15g of protein per serving, but 2g less carbs (1g less sugar). Flavor is Honey & Spice, which should go pretty darn well with almond milk. $34.99 for 16 servings.


  1. LP- the answer lies in the first paragraph of the quote, all drinks are already based on men’s physiology. If you have not been near a women while she is on varying stages of her cycle(menstrual), then you clearly have no idea why this product is needed. And if you have never met a woman, than that explains your question in the first place.

    My question is if our physiology actually changes throughout our cycle, why would there not be different formulas for the differing phases?? I would LOVE a miracle drink that would make riding easier while I’m on my period.

  2. @Emily- when your period starts, your hormones drop- this is what starts the bleeding. Women report they feel either fab or like crap on the day their period starts- this is when the hormones are in the most flux. And yes, I agree, there should be different formulas for the changing phases but in reality we can’t identify specifically when hormones change without blood tests. Knowing this, I formulated these to really help when you are most compromised (high hormone) and by design, help with low hormone (when things aren’t so out of whack and the body is under less stress). I’ve written quite a few articles on the differences between follicular and luteal phases and how your performance and recovery needs change.

  3. “women have been deemed ‘too difficult’ to be included in research because of these hormone fluctuations”- Very brave statement. Your obviously in a bunker under the Antartic while writing this.

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