How Does Arazlo Work? Mechanism of Action Explained in Plain English

You've probably heard that Arazlo is a retinoid that helps clear acne — but what does that actually mean? How does rubbing on a small amount of lotion once a day lead to fewer pimples? This guide explains exactly how Arazlo (tazarotene 0.045% lotion) works, in plain language you don't need a medical degree to understand.

What Is Arazlo? A Retinoid Prodrug

Arazlo is a retinoid — a class of compounds derived from vitamin A. More specifically, it belongs to the acetylenic class of retinoids and is classified as a prodrug — meaning Arazlo itself is not the active form. Once applied to the skin, it converts into the active drug through a natural chemical process.

Step 1: Conversion to Tazarotenic Acid

After you apply Arazlo to your skin, enzymes in the skin cells called esterases break down tazarotene through a process called esterase hydrolysis. This converts tazarotene into its active form: tazarotenic acid.

Think of tazarotene as a key that needs to be "cut" by the skin before it fits the lock. The skin does that cutting automatically once the lotion is applied.

Step 2: Binding to Retinoic Acid Receptors (RARs)

Once converted, tazarotenic acid travels into the nucleus of skin cells (keratinocytes) and binds to proteins called Retinoic Acid Receptors (RARs). There are three types: RAR-alpha (α), RAR-beta (β), and RAR-gamma (γ). Tazarotenic acid binds to all three, but shows preferential selectivity for RAR-beta and RAR-gamma.

This receptor selectivity is significant. RAR-gamma is the dominant receptor in the epidermis (the outer layer of skin), which is why tazarotene is particularly effective for skin conditions. This selectivity also distinguishes tazarotene from first-generation retinoids like tretinoin, which binds to all three receptors more equally.

Step 3: Changing Gene Expression in Skin Cells

When tazarotenic acid binds to RAR receptors, those receptors act as transcription factors — they travel to the cell's DNA and change which genes are "turned on" or "turned off." This gene expression change triggers several beneficial processes in the skin:

• Normalizes keratinocyte differentiation: Keratinocytes are the cells that make up most of your skin's outer layer. In acne-prone skin, these cells differentiate abnormally, sticking together inside hair follicles and forming comedones (clogged pores). Tazarotene normalizes this process, preventing pores from clogging.
• Reduces cohesiveness of follicular epithelial cells: Tazarotenic acid decreases how "sticky" the cells lining the hair follicle are, making it harder for dead skin cells and sebum (oil) to clump together and form blackheads or whiteheads.
• Reduces keratinocyte proliferation: By slowing the overproduction of skin cells, tazarotene reduces the buildup of dead cells that contribute to clogged pores.
• Anti-inflammatory effects: Tazarotene helps reduce the inflammatory response in the skin that leads to red, inflamed pimples (papules and pustules).

Why Does the Lotion Vehicle Matter?

Arazlo's unique polymeric emulsion technology is what makes it different from older tazarotene formulations. Here's how it works:

• Tazarotene (0.045%) is encapsulated within oil droplets suspended in a water-based emulsion
• Moisturizing agents (mineral oil, sorbitol, diethyl sebacate) are integrated directly into the vehicle
• When applied, the salts on the skin surface disrupt the emulsion, releasing both the active drug and the moisturizing components simultaneously

The result: you get the full therapeutic effect of tazarotene at just 0.045% concentration — with built-in moisturization that reduces the irritation, dryness, and peeling common with older 0.1% formulations. Phase 2 head-to-head data showed Arazlo achieved equivalent efficacy to Tazorac 0.1% cream with approximately half the adverse events.

How Long Before You See Results?

Because Arazlo works by changing gene expression and normalizing a biological process, it's not an overnight fix:

• Weeks 1–4: Skin adjustment period; expect some dryness, redness, and possibly an initial "purge" as pores clear out
• Weeks 4–8: Visible reduction in new lesions; skin irritation typically subsides
• Weeks 8–12: Full effect; Phase 3 trials showed peak benefit at 12 weeks with 55–60% reduction in inflammatory lesions

How Is Tazarotene Different from Tretinoin?

Both tazarotene (Arazlo) and tretinoin (Retin-A, Altreno) are retinoids that work through RAR receptors, but there are important differences:

• Receptor selectivity: Tazarotene is more selective for RAR-beta and RAR-gamma; tretinoin binds all three receptors more equally
• Potency: Tazarotene is generally considered slightly more potent for acne than tretinoin at similar concentrations
• Structure: Tazarotene has a more rigid chemical structure due to aromatic rings, making it more stable to light and oxygen and potentially less irritating than tretinoin (which breaks down into irritating byproducts)

For a head-to-head comparison of Arazlo versus other retinoids, see our guide to Arazlo alternatives.