Hormone Health guides
Practical, veterinary-led guidance on Hormone Health, written by vets, free to read. View all guides
Treating hyperthyroidism: the four options, compared honestly
When your cat is diagnosed with an over-active thyroid, you'll quickly notice that whoever you ask seems to favour a different treatment. That's not because anyone's being dishonest, it's because there are genuinely four good options, and the right one depends on your cat...
Alastair Greenway, BVM&S MRCVS · 9 min read
The over-active thyroid: why your older cat is wasting away despite eating everything
If your older cat is eating like never before and still getting thinner, it's natural to find that frightening. The most likely explanation is one of the most common things we see in senior cats, it's well understood, and it's very treatable.
Alastair Greenway, BVM&S MRCVS · 7 min read
Living with a treated thyroid cat: tablets, gels, rechecks and the long game
Once your cat's hyperthyroidism is diagnosed and you've settled on a treatment, the day-to-day becomes quite manageable. If you've chosen medication rather than a one-off cure like radioiodine or surgery, this article is about doing that medication well over the years…
Alastair Greenway, BVM&S MRCVS · 8 min read
The kidney catch: why treating the thyroid can unmask kidney disease
If your cat has just been diagnosed with an over-active thyroid, you'll probably have been told that it's common, well understood and very treatable. All of that is true. But one piece often gets left out of the first conversation, and it surprises owners...
Alastair Greenway, BVM&S MRCVS · 10 min read
Radioiodine: the one-and-done cure most owners aren't offered
Of all the treatments for an over-active thyroid, radioiodine is the one most likely to make an owner say "nobody told me that was an option." It cures the condition outright in the great majority of cats, with a single injection and no anaesthetic, yet plenty of cats are never offered it...
Alastair Greenway, BVM&S MRCVS · 6 min read
The under-active thyroid in dogs: the over-diagnosed, very-treatable one
If your dog has slowed down, put on weight without eating any more than usual, started seeking out warm spots, and lost coat in a thin, balding pattern that doesn't seem to itch, hypothyroidism is a fair thing to wonder about. It's a real condition, it's common, and here's the genuinely good news up front:…
Alastair Greenway, BVM&S MRCVS · 10 min read
The thyroid and the skin: coat changes, recurrent infections and the derm overlap
If your dog has been losing coat in a slow, even pattern, or keeps getting skin and ear infections that clear on antibiotics and then come straight back, the thyroid is one of the first things worth ruling in or out. The skin is the system most owners notice first with hypothyroidism, and skin or coat change is the…
Alastair Greenway, BVM&S MRCVS · 8 min read
Levothyroxine for life: getting the dose right and what to expect
This is one of the genuinely happy stories in this part of the site. Once your dog has a properly confirmed diagnosis of an under-active thyroid, the treatment is a small daily tablet that's cheap, safe and usually transformative, and most dogs brighten up noticeably over the following weeks...
Alastair Greenway, BVM&S MRCVS · 9 min read
Getting the thyroid diagnosis right: the tests, and the traps
If your dog has slowed down, put on weight without eating more, and started losing coat in a tidy, symmetrical, non-itchy pattern, hypothyroidism is a fair thing to suspect. It's a real disease, and once it's confirmed it's one of the most satisfying conditions in practice to treat. The catch is the word "confirmed".…
Alastair Greenway, BVM&S MRCVS · 9 min read
Cushing's explained: the thirsty, pot-bellied, balding dog
If you've ended up here, it's probably because your older dog has started drinking gallons, seems hungry all the time, wees more than they used to, and has developed a sagging, pot-bellied look with a thinning coat and a lot of panting...
Alastair Greenway, BVM&S MRCVS · 9 min read
Cushing's from steroids: the iatrogenic kind owners cause by accident
If your dog has been on steroids for a while, for itchy skin, an immune problem or joint disease, and is now starting to look a bit Cushing's-like, this is the article for you. The medical name is iatrogenic hyperadrenocorticism, which just means Cushing's caused by tr...
Alastair Greenway, BVM&S MRCVS · 8 min read
Treating Cushing's with trilostane: when to, when not to, and the monitoring
If your dog has just been diagnosed with Cushing's, the next conversation is usually about a tablet called trilostane. It's a well-understood drug that genuinely helps, and most dogs do well on it. But there are two things the single-product manufacturer pages tend to skip...
Alastair Greenway, BVM&S MRCVS · 9 min read
Diagnosing Cushing's: the testing maze (and the over-testing trap)
If your vet has mentioned Cushing's and then started talking about a morning of blood tests, a urine sample, maybe a scan, you'd be forgiven for thinking they're being indecisive. They're not. Cushing's is one of the few conditions in dogs where there genuinely isn't a single clean blood test that settles it…
Alastair Greenway, BVM&S MRCVS · 9 min read
Addison's, the great pretender: vague signs that crash into a crisis
If your dog has Addison's, or you think they might, and they suddenly collapse, go profoundly weak or wobbly, start vomiting or have diarrhoea, or feel cold and look shocky, treat it as an emergency and get to a vet now. Don't wait to see if it passes.
Alastair Greenway, BVM&S MRCVS · 8 min read
Living with Addison's: injections, tablets and a genuinely normal life
If your dog has just been diagnosed with Addison's, here's the part that often gets lost in the worry: this is one of the most rewarding chronic conditions there is to manage. Once your dog is stabilised on the right replacement hormones, the prognosis is excellent and life expectancy is essentially normal.
Alastair Greenway, BVM&S MRCVS · 8 min read
Diagnosing and surviving an Addisonian crisis
If your dog has Addison's, or you suspect they might, and they suddenly collapse, go profoundly weak or wobbly, start vomiting or have diarrhoea, or feel cold and look shocky, treat it as an emergency and get to a vet now.
Alastair Greenway, BVM&S MRCVS · 8 min read
Drinking gallons, always hungry, or fading? What the classic hormone signs mean
You've noticed something's off. The water bowl empties twice as fast, or your cat is eating like never before and somehow getting bonier, or an older dog has gone slow and round and just isn't quite right. You've typed "why is my dog drinking so much" or "cat losing weight but eating loads" into a search box...
Alastair Greenway, BVM&S MRCVS · 9 min read
Acromegaly and insulinoma: a signpost (owned by the Diabetes space)
This is a short one. Two conditions get a mention in this Hormone Health home but live properly in the Diabetes space, because both are really about blood sugar and insulin. If your vet has named one of them, or you've come across the word and want a calm sense of what it means, this is your map...
Alastair Greenway, BVM&S MRCVS · 8 min read
Conn's and the rarer adrenal problems worth a name
Most of this Hormone Health home is about the common conditions: the over-active thyroid cat, the over-diagnosed under-active thyroid dog, the thirsty pot-bellied Cushing's dog, the great-pretender Addison's. But the adrenal glands, the two small organs that sit just in front of the kidneys, can go wrong...
Alastair Greenway, BVM&S MRCVS · 10 min read
Diabetes insipidus: the water diabetes that is not about sugar
If your pet has just been told they have "diabetes insipidus", the most reassuring thing to know is this: it's not the sugar diabetes you have probably heard of. That one shared word makes it sound alarming, but it's a completely different disease, with a different cause, a different test and a different treatment…
Alastair Greenway, BVM&S MRCVS · 9 min read
Weight changed but nothing else did: when it's a hormone
You haven't changed the food. The walks are the same. Nobody's sneaking extra treats that you know of. And yet the scales, or the way your pet feels under your hands, say something has shifted. That quiet "I haven't done anything differently" is exactly the line that should make a vet reach for a blood test...
Alastair Greenway, BVM&S MRCVS · 8 min read
Drinking and weeing far more than usual: measuring it, and what it means
You've noticed the water bowl emptying faster than it used to, or you're refilling it twice a day when once was plenty. Maybe there are puddles where there never used to be, or the litter tray is heavier and you're scooping more. It's unsettling, and it's one of the most common reasons owners get in touch.
Alastair Greenway, BVM&S MRCVS · 8 min read
The hormone blood tests, explained (T4, ACTH stim, LDDST, basal cortisol)
Your vet has "run some bloods", or mentioned "a stim test", or said the first result "isn't quite enough on its own". If you're now staring at a form full of acronyms, this page is for you. It walks through the handful of blood tests behind the four common hormone diseases...
Alastair Greenway, BVM&S MRCVS · 8 min read
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