Tretinoin, explained properly

What tretinoin is

Tretinoin is retinoic acid — the biologically active form of vitamin A that skin cells actually respond to. Every over-the-counter retinol product is a weaker precursor your skin must convert, step by step, into this molecule before anything happens. Tretinoin skips the conversion and delivers the signal directly, which is why it’s prescription-only and why it remains the reference standard dermatologists measure newer ingredients against.

It has been prescribed since 1971 — first for acne, then for photoaging once researchers noticed what it did to skin texture and fine lines — which makes it one of the most-studied topical medications in existence. On Conduit, your formulation and strength are set by your physician and compounded for you by a licensed US pharmacy, which allows the strength, base, and any companion ingredients to be adjusted to your skin rather than picked off a shelf.

How it works

Skin renews itself on a cycle — new cells form in the deeper layers, migrate up, and are shed. That cycle slows with age, and the visible result is dullness, rough texture, and pigment that lingers. Tretinoin binds to retinoic-acid receptors in skin cells and speeds the whole program back up.

Three effects follow. Turnover accelerates, so fresher cells reach the surface sooner and dark spots break up and fade. Collagen production increases in the dermis — the structural layer — which is the slow, months-long remodeling that softens fine lines. And pores stay clearer, because the faster-shedding cells don’t linger and clog them, which is why the same molecule treats acne.

What the evidence shows

Tretinoin’s photoaging evidence comes from randomized, vehicle-controlled trials — the same design standard as any serious medication, rare in skincare. Across studies running 24 to 48 weeks, tretinoin consistently outperformed its placebo cream on fine wrinkling, surface roughness, and mottled pigmentation, with improvements that were graded by blinded investigators and, in several trials, confirmed under the microscope as new collagen formation.

Read the timeline honestly: texture and tone improve first, typically by weeks 8–12. Fine-line improvement is a collagen story, and collagen is slow — the trials that showed it ran six months to a year. Nothing visible happens in week two except, often, the adjustment below. Anyone promising otherwise is selling something.

The adjustment period, honestly

Dermatologists call it retinization — the weeks when your skin is learning to run at the new speed. It is the phase where most people quit, which is exactly why we describe it in advance.

1. Weeks 1–2

   The introduction

   Your physician starts you at a strength and frequency chosen for your skin — often every second or third night, not nightly. Mild tightness, dryness, or a faint sting on application are common and expected.

2. Weeks 2–6

   The visible adjustment

   Flaking and dryness usually peak here. Acne-prone skin sometimes “purges” — clogged pores surfacing faster than they otherwise would. It looks like a step backward; it’s the medication working through the backlog. This is what your check-ins are for: your physician can slow the frequency or adjust the strength rather than have you push through.

3. Weeks 8–12

   The turn

   Skin settles into the new rhythm. Texture smooths, tone evens, and the early dryness quiets. Most members are on their steady long-term frequency by now.

4. Months 3–6+

   The remodeling

   The collagen phase — the slow structural change the trials measured. Fine lines soften gradually, not dramatically, and the improvement compounds for as long as you stay consistent.

Using it well

Your physician sets your plan; these are the fundamentals that make any tretinoin plan work. A pea-sized amount covers the whole face — more isn’t stronger, it’s just more irritating. It goes on at night, because the molecule degrades in sunlight, and onto fully dry skin, because damp skin absorbs it faster than it should. Moisturizer is a teammate, not a cheat: applied after (or before and after, the “sandwich,” if your skin runs sensitive), it manages dryness without blunting the effect.

Keep it away from the corners of the eyes, nose, and mouth, where skin is thinnest. And pause before adding other strong actives — exfoliating acids, benzoyl peroxide, high-strength vitamin C — to the same routine; your physician will tell you what your skin can stack and what it can’t.

The non-negotiable: sunscreen

Tretinoin thins the outermost dead-cell layer and speeds turnover, which leaves skin measurably more sensitive to UV. Daily broad-spectrum SPF 30+ is therefore part of the prescription, not an accessory to it — every morning, regardless of weather, regardless of season.

There’s a second reason, and it’s the more important one: sun exposure is the single largest driver of the aging you’re treating. Running tretinoin at night and skipping sunscreen by day is rowing with one oar. The members who get the results the trials describe are, almost without exception, the ones who treat SPF as half the protocol.

Who it isn’t for

Pregnancy is the hard line: oral retinoids are established teratogens, and although absorption through skin is low, the standard of care is not to use tretinoin while pregnant, trying to conceive, or breastfeeding. Your physician will also want to know about active eczema or rosacea (which may need treating first, or a gentler ramp), a history of significant reactions to retinoids, and everything else currently in your routine — because the most common cause of a bad tretinoin experience isn’t tretinoin, it’s tretinoin stacked on top of three other actives.

That screening is the point of the intake. If tretinoin isn’t right for your skin right now, the physician’s job is to say so.