When my dog Sheba recently began displaying uncharacteristic lethargy, barely able to go out for short walks to the curb outside our building, I knew the culprit couldn’t be her osteoarthritis. After all, she’d just received a booster injection of her own stem cells, cultured by the brilliant team at Vet-Stem in San Diego, where my dog’s precious cells are kept in cold storage. A trip to the vet for a routine checkup and bloodwork confirmed my suspicion. Something else was indeed going on.

Thankfully, that something was fixable: Sheba’s thyroid wasn’t working properly.

In dogs as in humans, the thyroid is a small, butterfly-shaped gland located in the lower part of the neck. A gland’s function is to secrete hormones, and the hormones released by the thyroid deliver energy to all the body’s cells. In her advanced age — my sweet girl is now a grand lady of 16 — Sheba has developed hypothyroidism, which means that her thyroid is underactive. Typical symptoms are consistent with a slowdown in metabolism: fatigue, weight gain, and depression.

Incidentally, thyroid disease is not exclusive to seniors; hypothyroidism can manifest in young dogs (and human teenagers) as well. The respected veterinarian Jean Dodds, founder of HemoPet, recently write a book, The Canine Thyroid Epidemic (Dogwise Books), all about this sad medical phenomenon.

For human patients, doctors’ RX is a synthetic replacement called Synthroid. Chances are you know someone who’s on this medication (I know two: one is 82 and the other is only 16). The veterinary equivalent is called Soloxine, and is precisely what Dr. Rubinstein of the Humane Society of New York prescribed for Sheba: 0.3 milligrams, to be exact, to be administered twice a day. Fortunately, it’s a tiny pill, and despite its bright-blue hue, Sheba never even notices it mixed up with her food (which is already souped up with cinnamon, turmeric, Nordic Naturals Omega 3 Pet, honey, and coconut oil; among coconut oil’s many health benefits is that it helps promote normal thyroid function).

Of course, I’m always interested in natural ways to keep my pets at their peak of wellness (and keep them away from the vet’s office), so I began investigating alternatives. First, I added Pet Sun Chlorella to Sheba’s diet. This green-algae dietary supplement, the human form of which I also take when I need to detox, helps improve thyroid function, among other things. I’ve eliminated peanut butter from Sheba’s snacking repertoire, as avoiding peanuts is recommended for anyone with thyroid disease. And I’m very glad that I don’t drink — or serve my dogs — fluoridated New York City tap water unless it’s properly filtered; according to the National Resource Council, there is clear evidence that small amounts of fluoride, an insidious neurotoxin, at or near levels added to U.S. municipal water suppliespresent potential risks to the thyroid gland.

Next, I consulted with my brilliant friend Mary Shomon, nationally recognized patient advocate, bestselling author, and About.com columnist (follow her on Twitter). She has firsthand experience with thyroid disease, which is why she’s so passionate and knowledgeable; not only does she live with it, so does one of her beloved Bichons, Sammy. At the recommendation of her vet, Kitty Raichura of Veterinary Holistic Care in Bethesda, MD, Sammy takes Thytrophin, a glandular supplement formulated for humans.

So I called Dr. Raichura, who graciously consulted with me and recommended that I give Sheba Thytrophin too, to see if perhaps, after a period of taking this supplement, a blood test might reveal that the twice-daily Soloxine dosage could be safely lowered. That’s what she does with her own beloved Boxer; amazingly, at the tender age of 2, he already has hypothyroidism! But, the vet added solemnly, “You’re on borrowed time.”

Well, yes, that is harsh but true — to a point. Isn’t the reality that all of us, human and K9, are on borrowed time, whether we’re young or old, healthy or not-so? My philosophy is to live life to the fullest, right now. Take every chance.

Try and tell me that isn’t every dog’s philosophy too.

I’m happy to report that, after a few weeks of taking Soloxine, Sheba’s energy level is almost back to normal. Just the other day, she brought a smile to my face by happily scampering through our lobby as we headed to the park for a romp (see above video). Okay, so it wasn’t a high-speed romp — but it wasn’t super-slo-mo, either! I hope to see this trend continue, and I’ll be sure to report on Sheba’s progress after her next blood test.

Meanwhile, Dogsters, do you have a dog with thyroid disease? Please share coping tips in the comments!