You'll find with the higher end pharma grade HGH products (especially Saizen), that it's made with such meticulousness that you won't get sides like CTS, but it will make you sleepy as fuck! They're produced for kids with growth deficiencies who take it at night time before sleep, so it's great for them.

But as for expiry dates, you're right it's a very subjective matter. Generally the way it works is, that when the product is manufactured, the hormone is already degrading, but at a very minimal and slow rate. The expiry date is the estimated/approximate date in which the hormone will have degraded past an acceptable level and lose it's potency and effectiveness. The pharmaceutical companies generally are prudent with their expiry dates as they don't want to be held negligent for a medication not working on a patient, so generally speaking you're still good to go with most pharma grade products a good few months after the expiry dates, in some cases even a year or more past the expiry date.

If you got zero affects at all from the expired product you were using from the other source then most likely it had degraded badly or it was fake, or maybe it wasn't stored properly which accelerated the degrading.