I Used My Hormones as a Horoscope and It Worked

"I'm feeling amorous." I sidle up to my husband in the kitchen one night while we're making dinner.

"I can see that," he laughs.

"How can you tell?" I thought I was being coy and seductive.

"Because you're wearing lingerie to heat up lentil soup."

I raise my eyebrows up and down. I'm going for Sophia Loren but it's coming off as Pepe Le Pew. I am at the mercy of my hormones.

As much as I would like to see this seduction through, I retreat to my study to write the episode down in my new "hormone journal," a daily account of my moods, productivity, diet, exercise and libido. I'm road-testing Hormone Horoscope, a website and app that offers daily forecasts for women, based on where they are in their menstrual cycles.

Gabrielle Lichterman, a health journalist, started Hormone Horoscope while researching a study about how women's preference for partners can change according to where they are in their cycle. The study found that around ovulation, which typically occurs around Days 12-14 women were attracted to more rugged, masculine men.

It gave her an idea. Over a period of years, she searched journals, went through thousands of other studies, anything to do with menstrual cycles and behavior, and started filling them into a calendar.

"One study would find energy is high near ovulation," she says. "Then another would find that sleep is more difficult during your premenstrual week. Then another study would find that sleep is better during rising estrogen days."

She started keeping a detailed journal of her own behaviors, and cross-referenced.

"It soon became apparent that hormones impact virtually every aspect of our lives. So that you could – starting with the first day of your period and ending with the last day of your cycle – see exactly what was going to happen to you on every day."

Most menstrual cycles range from 21 to 35 days. Throughout, three key hormones, estrogen, testosterone and progesterone, rise and fall. On Day 1 of a woman's period, when estrogen is at its lowest, there's fatigue, not wanting to leave the house. As estrogen rises, energy increases, and women may feel sharper, more talkative, more adventurous, even have a little less of an appetite.

Testosterone kicks in in Week 2, which contributes to an increased libido.

Week 3, Progesterone kicks in, and with it, a bit of lethargy and cravings for comfort-foods. During Week 4, estrogen nosedives and here's where PMS typically kicks in – insomnia, emotional sensitivity, and sometimes even physical symptoms like headaches. Of course PMS is also affected by diet, exercise, and any medication a person might be on, as well.

Men have a hormone cycle too. Theirs is 24 hours and a little more straightforward, with highest testosterone at the beginning of the day (ex – morning wood), declining as the day goes on.

I was skeptical. I have regular periods and minimal PMS, maybe tearing up at a father-daughter McDonald's commercial a couple of days before my period.

I started a daily journal, writing down my own behaviors and patterns. Lichterman tells me to include social life, shopping patterns, and confidence level. Things that, to me, didn't seem relevant.

It wasn't until I was halfway through painting my living room one afternoon – the idea was to paint an accent wall, but it looked so good, and I was blasting The Best of Blondie and I had a lot of energy, just paint the whole damn room‑‑it wasn't until then­­‑‑that I stopped, paint roller in one hand, wondering if this sudden burst of energy might have something to do with my menstrual cycle.

I checked the calendar, then the app.

Day 13 of my cycle. High estrogen and testosterone, which translates to high confidence and revved energy.

"You may feel like you can push yourself more physically," it reads.

I was approaching ovulation. I could have honed my Promethean impulses to create a new human life, I guess. But instead, I have a very nice buttercream-colored living room.

A week or so later, my husband and I went to brunch and I ordered macaroni and cheese. I ate the entire thing. I felt terrible after – sluggish, bad about myself. I forced myself to exercise, but a simple hike felt like monumental effort. I was exhausted.

"Do you think I have lupus?" I asked my husband when I got home from the hike. "I'm so tired." He laughed and said I say that a lot. I wondered - once a month?

That night we watched Working Girl, which I hadn't seen in ages. I paused it and turned to Hugh.

"Has NOTHING changed?"

"What are you talking about?"

"There's this ILLUSION of progress with the women's movement, but has anything changed since Working Girl?" I was near tears. Hugh froze. It was like that scene in Jurassic Park with the T-Rex breathing right outside the van. I was the T-Rex.

The next day, I woke with a sore throat. Goddamn it, I'm getting sick, I thought.

I checked Hormone Horoscope for Day 26. Plunging estrogen. "This plummeting hormone is also the reason you may feel like you're coming down with a cold."

How does it know?

A couple of days later I get my period and debate canceling lunch plans I have with a friend. I check the app for Day 1. "Fatigue may make you wish you could cancel all your plans …"

I start to wonder if Lichterman is a witch.

"That's science," she laughs when I call and tell her about the eerie accuracy I am finding in her daily horoscopes. It's something she hears from women a lot.

"There's a certain level of peace and acceptance that come from knowing how your hormones will be impacting you," she continues. "For instance with the macaroni and cheese. You can cut yourself some slack. It's a physiological response to hormones."

I felt like a cliché – all this eating and shopping and emotional sensitivity. My hormonal destiny is turning me into a Cathy comic strip. Is there another way to look at this? When is a good day for a corporate takeover? To fly to the space station?

"When I first started this, I got pushback from women who thought I was pushing the women's movement back 100 years," Lichterman says. Reinforcing the stereotype that women can't control their hormones, that they're more emotional, moody at certain times of the month. I hate this idea myself. But after talking with Lichterman, I see the science. What if I didn't frame it as a weakness?

Lichterman offers there's power in knowing how your hormones are influencing you as opposed to being a slave to your cycle.

"You can kick-ass on a job interview because you picked the right day," she says. "The real slave is the person who doesn't know why they need to spend $100 on a top (she is referring to me and the overpriced shirt with stars all over it that I bought on Day 12) as opposed to the woman who says, 'This is plunging estrogen that is causing a dip in serotonin that makes me want to splurge.'"

Incidentally, Week 2 of your cycle is probably the best time to schedule that corporate takeover. Confidence, energy, and brain skills are at their peak.

Women with irregular cycles can use the app, re-setting on the first day of their periods. But it's not for women with Polycystic Ovary Syndrome or on hormonal birth control, whose hormone levels have different patterns.

I found women all over the world who swear by it and check it daily.

Tanveer Parmar, an HR Manager in Mumbai, told me she plans business meetings with new clients and networking during the first two weeks of her cycle, and meets with colleagues and friends she has known for a while during the last two weeks, "as there is a sense of comfort to be around them," she says.

It's also helped her to be less hard on herself.

"I would berate myself for not feeling happy and upbeat," she says, "Now I know that a mini-PMS hits me during Week 3."

Becky Grigsby, an artist and mom of two living in Oakland, California, echoed, "I check it (the app) when I'm feeling moody for no obvious reason to confirm that it's probably hormone related."

Lichterman's horoscopes repeat each cycle – for example "Day 26" is the same horoscope each month. But that's because the patterns in a woman's cycle – even if it varies in length – also repeat themselves.

Of course there are variations among individuals, which is why Lichterman recommends women (and men) keep a journal for a few months to track their own personal changes.

"I don't want people to rely on my app," she says, "I want women to learn it and rely on themselves."