The Complete Retinoid Guide: Everything I Tell My Patients Before They Start
This is the post I wish existed when I started in Dermatology. Everything I know about retinoids--the science, the types, the routines, the myths, the mistakes, in one place. No fluff, no sales pitch.
If you’ve been following me for any amount of time, you already know that retinoids and SPF are my two non-negotiables. If I had to strip my entire philosophy down to two ingredients, it would be those, every single time. And of the two, retinoids are the one that gets the most questions — the most fear, the most confusion, the most misinformation.
So consider this the definitive retinoid post. The one I’ll point people to from now on.
What Retinoids Actually Are — And Why the Terminology Matters
“Retinoid” is the umbrella term. It covers every topical vitamin A derivative, both over-the-counter and prescription. Retinol is one type. Tretinoin is another. Retinaldehyde is another. They are not all the same thing, and treating them as interchangeable is one of the most common mistakes I see.
Here’s the conversion chain, and why it matters:
Retinol → Retinaldehyde → Retinoic Acid
Retinoic acid is the active form — the molecule that actually interacts with your skin cells to drive results. Every other form on this list has to convert to retinoic acid before it can work. The fewer conversion steps required, the faster and stronger the results — but also the higher the potential for irritation.
This is why tretinoin, which is retinoic acid, delivers faster and more dramatic results than retinol. It doesn’t need to convert. It’s already in its active form. It’s also why it requires a prescription and why I don’t recommend starting there unless a provider has recommended it.
The Retinoid Spectrum: A Clinical Breakdown
Retinol. The most widely available and the most commonly used starting point. Requires two conversion steps to reach retinoic acid. Slower to show results, but more forgiving for beginners. Effective for fine lines, uneven tone, and minor blemishes when used consistently. The key phrase being consistently — this is a long game.
Retinaldehyde / Retinal. One conversion step away from retinoic acid. Faster results than retinol and — counterintuitively — often better tolerated. This is my favorite recommendation for sensitive skin types who still want clinical results without a prescription. It’s having a real moment in the skincare world right now, and the clinical data warrants it.
Adapalene 0.1% (Differin). This one deserves its own paragraph. Adapalene is a third-generation synthetic retinoid that was prescription-only for decades. It binds more selectively to retinoid receptors than retinol, which is part of why it’s so effective for acne — and why it causes less generalized irritation in many people. The fact that you can now buy it at Target for under $30 is amazing. If acne is your primary concern, this is almost always my first recommendation.
Tretinoin (Prescription). The gold standard. Retinoic acid in its active form — no conversion required. Fastest and most clinically significant results across the board. Requires a derm provider, needs careful introduction, and is not where anyone should start. But if you’ve been using OTC retinoids consistently for 6–12 months and you’re ready to graduate, this conversation is worth having with your provider.
Who Should — & Shouldn’t — Use Retinoids
Almost everyone can benefit from a retinoid. The question is which one and how.
Retinoids are excellent for:
Anyone in their 20s, 30s or 40s looking to prevent early signs of aging and hyperpigmentation
Anyone dealing with breakouts, regardless of age
Anyone with uneven texture, enlarged pores, or dullness
Older adults addressing more pronounced fine lines, deeper pigmentation, and reduced skin density
Do not use retinoids if you are:
Pregnant— this is a firm clinical contraindication, not a suggestion
Dealing with active eczema, rosacea, or a significantly compromised barrier — not forever, but not right now. Get the barrier stable first, then reassess with your provider.
You now know what retinoids are and whether you should be using one. What comes next is the part most people get wrong — the exact routines, the clinical framework I use in clinic to match patients to the right strength, my exact product picks by level, and the myths I’m still hearing daily. All of that is below for paid subscribers.
