In August, Ryan Samluk’s beloved Australian-German Shepherd mix, Finley, suffered a devastating sprain.

The 11-year-old dog had long lived with hereditary joint issues. Now, she could barely limp around the yard.

“I knew the vet visit would cost thousands of dollars I didn’t have,” Samluk, a 29-year-old project manager for a construction company in Dallas, told Business Insider.

Unwilling to watch his dog suffer, yet unable to afford costly diagnostics plus regular arthritis shots at $200 per dose, Samluk turned to the internet. For about $160, he bought his old girl a month’s worth of peptide treatments, the unregulated shots that are taking…