Supposedly, the menstrual cycle is a gift. It’s a product of good design. It’s a miraculous dance of hormones that can’t be contained. Such are the messages flooding the internet these days, courtesy of lifestyle influencers, crunchy moms, so-called hormone coaches, and all sorts of popular entertainers. The menstrual cycle, according to these same voices, is also an emotional roller coaster, best ridden with the aid of bespoke products. Viral memes and TikTok trends play up women’s purportedly excessive spike in libido during ovulation and dramatic irrationality during menstruation and the luteal phase (the 14 days or so between ovulation and menstruation). The cycle-tracking app Belle Health has used Moana’s verdant mother goddess and her volcanic counterpart to illustrate the difference. The meal-kit company Hungry Root recommends ordering sweets during the luteal phase. Every stage of the cycle has its own skin serum. You can test your hormone levels at a boutique women’s clinic, or at home using a $100-plus device and a monthly app subscription. (Evidence for the efficacy of most of these tests, …