“Retinol” and “retinoid” get used almost interchangeably in skincare marketing, but the distinction matters for what to expect.
Retinoid is the umbrella term for all vitamin A derivatives used in skincare, ranging from gentle over-the-counter forms to prescription-strength tretinoin. Retinol specifically refers to one particular over-the-counter retinoid — generally the mildest commonly available form, requiring conversion by the skin to become active, which is part of why it tends to cause less irritation than prescription options.
Prescription retinoids like tretinoin are already in their active form and significantly more potent — more effective for some concerns, but with meaningfully higher irritation potential, especially when starting out.
For beginners, starting with retinol a few nights per week and slowly increasing frequency, rather than jumping straight to prescription strength, is the generally recommended path to build tolerance.