Cat lost weight

[tortoise2022]

My cat as hyperthyroidism and has been on daily medication for a couple of years now. She has lost 0.38kg since this time last year which has been part of a gradual weight loss over the last 5 years. Should I be really worried? She's about to turn 19 years old and generally seems a happy cat. She has always been quite small and slender, often mistaken for a much younger cat because she's so dainty. I'm not sure what level of weight loss is normal in aging cats. Thank you!

I'd like to know too. My 12 year old had bloods done in February that were all fine. But in the last 18 moths or so. She's lost about 1.3kg. She's otherwise completely fine, and eating and drinking as normal. And her coat is in good condition. She does seem to have stabilised though. But weighed her for a while.

Apart from the thyroid, my girl seems in good health. She's eating and drinking well, again her coat looks healthy and she seems happy in herself. She sleeps a lot but then she's an old lady. I'm wondering whether it's just part of her getting older?