Beginner’s Guide to Retinoids: Retinol, Retinal & Retinoic Acid Explained.
Retinoids are one of the most researched and effective ingredients in skincare. They are widely known for improving skin tone, texture, acne and signs of ageing. However, many patients feel unsure about which form to use and how to use them safely.
Understanding the differences between retinol, retinal and retinoic acid can help you achieve the best results while minimising irritation.
What Are Retinoids?
Retinoids are derivatives of vitamin A. Once applied to the skin, they are converted into retinoic acid, the active form that works within skin cells to stimulate renewal and collagen production.
Different types of retinoids convert at different speeds and strengths.
The Conversion Pathway Explained
To work effectively, retinoids must be converted into retinoic acid in the skin:
Retinol → Retinal → Retinoic Acid
Retinol requires two conversion steps
Retinal (retinaldehyde) requires one conversion step
Retinoic acid (tretinoin) is already in its active form
Vitamin A Conversion Pathway
Retinol (Vitamin A)
⬇️ (2-step conversion in the skin)
Retinal (Vitamin A – stronger form)
⬇️ (1-step conversion in the skin)
Retinoic Acid (Active Vitamin A)
⬇️
Skin Cell Renewal & Collagen Stimulation
All forms of Vitamin A must be converted into retinoic acid to become active in the skin. The fewer conversion steps required, the stronger and faster the effect but the higher the risk of irritation.
Key Differences Between Retinoids
Retinol
Retinol is the most commonly used form in professional skincare.
Benefits:
improves skin texture
brightens skin tone
reduces fine lines
helps with acne
It works gradually and is ideal for beginners when introduced slowly.
Retinal (Retinaldehyde)
Retinal is one step closer to retinoic acid, making it:
more potent than retinol
faster acting
still suitable for many skin types with guidance
It often provides quicker visible results but requires careful use.
Retinoic Acid (Tretinoin)
Retinoic acid is the active prescription form.
Benefits:
strongest clinical results
treats acne and ageing effectively
Because it is already active, it can cause irritation if not used correctly and should only be used under professional supervision.
Why You Must Start Slowly
Retinoids increase cell turnover, which can initially cause dryness, redness and sensitivity. Starting slowly allows the skin to adapt safely.
Recommended Build-Up Schedule:
Month 1: 2 nights per week
Month 2: Every other night
Month 3: 5 nights on, 2 nights off
This gradual approach helps minimise irritation and improves long-term tolerance.
Evening Use Only
Retinoids should be used in the evening only because:
they can make skin more sensitive to sunlight
they may degrade when exposed to UV light
Always apply to clean, dry skin and follow with a moisturiser if needed.
SPF Is Essential
When using retinoids, daily SPF is non-negotiable.
SPF helps:
protect your skin from UV damage
prevent pigmentation
avoid irritation and sensitivity
maintain the benefits of retinoid use
SPF should be worn every morning, regardless of the weather or season.
Who Should Use Retinoids?
Retinoids can help with:
uneven skin tone
acne and breakouts
fine lines and wrinkles
sun damage
dull skin
They are suitable for many skin types when selected and introduced correctly by a professional.
Common Mistakes to Avoid
Using too often too quickly
Mixing too many active ingredients together
Skipping moisturiser
Forgetting SPF
Applying in the morning
Professional guidance can help prevent these mistakes.
Final Thoughts
Retinoids are a powerful tool in skin rejuvenation when used correctly. Understanding the differences between retinol, retinal and retinoic acid allows you to choose the right product and use it safely for long-term skin health.
At Fine Aesthetic Medicine Clinic, we believe in educating patients and creating personalised skincare plans that achieve visible results while protecting the skin barrier.