Are hair oils actually safe as heat protectants?

This is contested. Brands like Olaplex and L'ANZA market heat protection up to 450°F, and verified-purchase reviewers report no issues. But r/HaircareScience commenters and at least one stylist quoted in those threads argue that oils heat up under styling tools and can compound damage. If you want guaranteed heat protection, a dedicated thermal spray is the safer bet; treat oil's heat claim as a bonus, not a primary defense.