Updated: April 2026
Retinoids are vitamin A–derived compounds used in both skincare and dermatology. While the term is often associated with retinol, it actually refers to a broader family of ingredients that differ in structure, strength and how they’re used.
This guide focuses on the retinoid family itself — what qualifies as a retinoid, how different forms are grouped, and how they’re classified. For a broader introduction, see retinoids explained.
Jump to:
- What Qualifies as a Retinoid?
- Conversion-Based Retinoids (The “Big Three”)
- Other Retinoids in the Family
- Retinoid Classification Overview
- Over-the-Counter vs Prescription Retinoids
What Qualifies as a Retinoid?
A retinoid is defined by its ability to interact with retinoic acid receptors in the skin.
These receptors influence how skin cells behave, which is why ingredients like retinol, retinal, tretinoin, adapalene and tazarotene are all classified as retinoids. While they differ in structure and use, they all act within the same biological system.
Conversion-Based Retinoids (The “Big Three”)
Retinol, retinal and tretinoin are often grouped together because they follow the same conversion pathway.
In simple terms, the skin converts one form into another before it becomes fully active:
- Retinol converts to retinal
- Retinal converts to retinoic acid
- Tretinoin is already retinoic acid
Because they share this pathway, these forms are frequently compared.
For a clearer side-by-side breakdown, see retinol vs retinal vs retinoic acid.
Other Retinoids in the Family
Not all retinoids rely on this conversion process.
Adapalene and tazarotene are synthetic retinoids. Instead of converting into retinoic acid, they are designed to interact directly with retinoid receptors.
Although their pathway differs, they are still part of the same family because they act on the same receptor system in the skin.
Retinoid Classification Overview
The retinoid family can be grouped by how each form becomes active and how it’s typically used.
Retinyl Esters (e.g. retinyl palmitate)
Availability: Over-the-counter
Common use: Gentle, long-term maintenance and early visible signs of aging
Activation: Require multiple conversion steps
Retinol
Availability: Over-the-counter
Common use: Uneven texture, mild breakouts, early photoaging
Activation: Requires two conversion steps
Retinal (retinaldehyde)
Availability: Over-the-counter
Common use: Acne and more visible tone changes
Activation: Requires one conversion step
Tretinoin (retinoic acid)
Availability: Prescription (in most regions)
Common use: Acne, established photoaging, certain pigmentation concerns
Activation: Already active
Adapalene
Availability: Prescription (OTC in some regions)
Common use: Acne management
Activation: Direct receptor interaction
Tazarotene
Availability: Prescription
Common use: Acne, psoriasis, advanced photoaging
Activation: Selective receptor activity
Over-the-Counter vs Prescription Retinoids
Another way retinoids are grouped is by how they’re regulated and used in practice.
Over-the-Counter Retinoids
These are found in cosmetic skincare products and are designed for gradual, long-term use. Most require conversion within the skin before becoming active, which generally leads to slower and more progressive results.
They’re typically used for early signs of aging, uneven texture, mild breakouts and overall skin maintenance.
Prescription Retinoids
These are regulated as medications in many countries and prescribed for specific dermatological conditions. Because they act more directly in the skin, their effects tend to be more targeted.
They are commonly used for:
- Acne, including persistent or inflammatory forms
- Established photoaging
- Hyperpigmentation
- Psoriasis (particularly with tazarotene)
The Bottom Line
Retinoids are a diverse group of vitamin A–derived compounds, defined by how they interact with the skin rather than how they’re structured or used.
Understanding how they’re grouped by activation pathway, strength and regulation makes it easier to navigate the retinoid family as a whole.
For a deeper look at this process, see how retinoids work in the skin.
More From the Retinoids Series
How to Start Using Retinol
Retinoid Irritation vs Purging — How to Tell the Difference
How Often Should You Use Retinoids?
What Not to Use With Retinol
