Viking Therapeutics stock plunged early Thursday on an earnings report that included mostly incremental updates for its weight-loss drugs.

And with a growing number of companies in the GLP-1 space, investors may be losing interest in the stock. Could Viking's rapidly declining valuation be a sign that the bubble has burst for it, given its inflated price, or is the healthcare stock due for a big rally this year?

Viking Therapeutics Inc.’s stock jumped 3% Tuesday, after a bullish note from Oppenheimer highlighted the company’s promising obesity-drug program and its potential appeal to a deep-pocketed partner.