And in the medicinal world, every single part of that deer is considered valuable.

The antlers are often for sale, presented in an elaborate gift box almost like moon cakes. They’re not eaten whole, but ground up and mixed with warm water, until it becomes gluey. Deer Antler Glue (鹿角胶, lù jiǎo jiāo , 70 RMB / 250g), reputed to tone the kidney, remove obstructions in meridians, help produce breast milk, and—like many of these remedies, it seems—boost the libido. It balances the pairing of yin and yang, and even helps women with menstrual troubles.

One of the few authorized producers of Deer Antler Glue in China is an ancient Beijing pharmacy called Tongrentang. It opened for business eight years after the start of the Qing Dynasty, in 1669, and has been operating at the same location in Beijing since 1702.

Like the “Compendium of Materia Medica,” it’s a TCM institution and its cabinets are filled with a world of strange TCM—sea cucumbers, sea horses, and snakes—but one thing we didn’t find there was deer embryo. 

It’s an ancient remedy for women who have trouble getting pregnant, and according to Chen Shiduo’s “The New Materia Medica” (《本草新编》běn cǎo xīn biān ), published in 1691, it will “invigorate the function of the spleen, reinforce kidney yang, tonify qi, and produce vital essence.” 

All the embryos have already sold out this year,” Dr. Bai Xiaofeng told us. He’d spent months trying to find one for his daughter. It took many failed attempts, and some personal connections, to finally get his hands on one.

I asked my daughter to take three spoonfuls of the ground-up powder a day,” he told us. “She didn’t like it—it smells so bad. But she was pregnant by the third week. I asked my wife to finish the rest. You see, deer embryo is expensive, and not a speck should be wasted.” 

The owner of the Zhaofeng Deer Farm refused to give her name, but enthusiastically agreed with Dr. Bai. “Deer embryo is especially good for women,” she said. “Men can take it as well, as a tonic.”

But her favorite suggestion for a men’s tonic is actually made from the loin of a male deer.Private parts appear frequently in TCM. The basic concept behind it all is that you can improve any organ in your body by eating that same organ of an animal. You are what you eat, or—literally in Chinese—“eat something, nourish something.” (吃什么补什么。chī shén me bǔ shén me. )

Today, deer parts are priced for the gentry (400 RMB for a 100g member) and are recommended mostly for the older set. “Young men should leave it to their elders,” said Xie Chongyuan, a professor at Guangxi TCM University. “They should focus on a healthy lifestyle, not on drinking tonics.”

But if you do want to prepare that tonic, slice the meat thinly, and soak the strips in a liter of strong alcohol for about two weeks. Twenty milliliters of liquor a day should be enough to help the adrenals, boost testosterone, and improve function.

In ancient times, this tonic was legendarily popular with the emperors. But when you remember the number of wives and concubines they often had, that’s not so entirely surprising.