What You Need to Know About Using PHAs, AHAs and BHAs with Retinol
Written by: Radhika Sen
Updated on: 3 Mar 2025
If you’re a skincare enthusiast with a cabinet chock-full of active ingredient heavyweights like exfoliating acids (alpha-or beta-hydroxy) and retinol, we can easily relate. Despite that passion, we wouldn’t blame you for not knowing whether it’s safe to use these retinoids and acids together.
Acids, such as AHAs, BHAs, and PHAs, exfoliate and rejuvenate the skin, while retinoids, derived from Vitamin A, promote cell turnover and reduce the signs of ageing. There’s often a lot of misinformation surrounding retinol not playing well with other skincare ingredients. For instance, should retinol be used in the same routine as other actives? Or about the combination of retinol with AHA’s & BHA’s being harmful to your skin?
As experts in vitamin A, we will delve into the synergistic benefits of combining these ingredients and provide a comprehensive guide on effectively incorporating these powerhouse ingredients into your skincare routine.
What are acids: AHAs, BHAs and PHAs?
Acids in skincare are exfoliating agents that help to remove dead skin cells, promote cell turnover, and improve skin texture and appearance. Each type of acid works differently and is suited for various skin types and concerns.
| AHAs | BHAs | PHAs | |
|---|---|---|---|
| Used for | Skin exfoliation | Acne, blackheads and blocked pores | Exfoliation and hydration |
| What it is | Water-soluble acid, usually derived from sugary fruit | Oil-soluble acid that penetrates deep into the skin | Water soluble with a larger molecule size |
| Skin type | Normal to dry | Oily and sensitive | All skin types |
| Potential side effects | Redness, dryness and irritation | Peeling, redness, increased sensitivity to sunlight | Mild redness, slight irritation, tingling sensation |
| Where it acts | Upper skin layers | Deep pores | Skin surface |
| What it does | Exfoliates dead skin cells, improves texture and tone | Clears blackheads, whiteheads and | Eliminates dead cells and helps maintain skin’s hydration |
| When to use | Day & Night | Day & Night | Every routine, Day & Night, 2-3 times a week |
| Avoid use with | Benzoyl peroxide and physical exfoliating scrubs | Benzoyl peroxide | Vitamin C and Benzoyl peroxide |
| Examples | Glycolic Acid, Lactic Acid, Mandelic Acid | Salicylic acid | Gluconolactone, Galactose and Lactobionic |
What are retinoids?
Retinoids are a class of compounds derived from vitamin A that are dermatology’s gold-standard topical agent to treat early signs of ageing. Several derivatives of retinoids, from the most common retinol to prescription-strength tretinoin, each offer varying levels of potency and effectiveness. They promote cell turnover, enhance collagen production, and improve skin texture and tone. In doing so, retinoids address skin concerns like fine lines and wrinkles as well as hyperpigmentation.
To be effective on the skin, vitamin A must journey through the 'vitamin A pathway' to transform into its biologically active form, 'retinoic acid'. Each retinoid represents a different stage of this pathway, influencing its strength, method of action, and overall effectiveness on the skin. Understanding the different types of retinoids can help you choose the best one for your skin type and concerns.
Mixing retinoids and acids
Mixing retinoids and acids in skincare is a topic often surrounded by myths and misunderstandings, particularly regarding their pH levels neutralising each other. It's essential to debunk these misconceptions with scientific clarity.
Retinoids, such as retinol and tretinoin, work by binding to specific receptors in the skin to promote cell turnover and collagen production. They do not significantly alter the skin's pH nor do they exfoliate the skin like acids do.
Acids, including AHAs (Alpha Hydroxy Acids) and BHAs (Beta Hydroxy Acids), exfoliate the skin by loosening dead skin cells, enhancing skin radiance, and promoting a smoother complexion. They typically operate within a lower pH range to exert their exfoliating effects.
There’s no research demonstrating the acidity of chemical exfoliants disrupts retinol's ability to work its anti-ageing, skin-smoothing benefits. On the contrary, combining acids with vitamin A is effective in reducing hyperpigmentation and blemishes.
Can you use retinol in the same routine as other active ingredients?
Yes, you can, but timing and careful consideration are essential to avoid potential irritation. When introducing new active ingredients, such as retinol and acids, it's especially important to be cautious.
Overloading the skin with too many actives can compromise the skin barrier, particularly for those with sensitive skin. To minimise irritation, we recommend introducing new products gradually, ensuring that your skin has time to adapt. Monitor how your skin responds and adjust your routine accordingly to maintain balance and avoid overwhelming your skin with too many new ingredients at once.
Potential Risks and Side Effects:
- Increased risk of dryness, peeling, or redness, especially if both ingredients are used simultaneously without proper tolerance assessment.
- Heightened sensitivity to sunlight, necessitating the use of sunscreen during the day.
- Irritation or discomfort for individuals with sensitive skin, requiring an adjustment in product frequency or formulation.
At Medik8, our products are expertly formulated to work together for maximum effectiveness. For instance, while combining BHAs or AHAs with retinoids isn’t typically recommended, you can safely layer Press & Clear with your chosen vitamin A at night for clear, smooth skin. Similarly, Sleep Glycolic and Vitamin A can be layered once you've gradually introduced retinoids into your routine. This thoughtful combination approach ensures your skin gets the full benefits without overwhelming it.
Using acids and retinol in your skincare
When incorporating acids and retinol into your skincare routine, it's essential to consider what's best for your skin’s overall health. Both ingredients provide significant benefits, but their potency means they need to be integrated carefully to avoid irritation and achieve optimal results.
Acids, like BHAs and AHAs (mandelic and lactic acid), are often found in toners and cleansers. They gently exfoliate, unclog pores, and improve skin texture. Retinoids, commonly found in creams, oils, and serums, work to boost cell turnover, smooth fine lines, and enhance skin clarity.
When incorporating acids and retinol into your skincare routine, we would highly recommend considering what is ideal for your skin's overall health. Both ingredients offer significant benefits, but their powerful effects require careful integration to avoid irritation and maximise results.
To combine these powerful ingredients effectively:
- AHA/BHA cleansers followed by a retinoid serum can help enhance exfoliation while being gentler on the skin.
- AHA/BHA/PHA toners paired with vitamin A products, like a retinol cream, can offer more noticeable results but come with a higher chance of irritation if used in the same routine.
Medik8 offers a range of expert-led formulations that harness the power of these ingredients. Surface Radiance Cleanse is a powerful AHA/BHA cleanser that refreshes and exfoliates the skin. For retinoid treatments, Medik8’s iconic vitamin A night serum Crystal Retinal is clinically proven to work visibly smooth stubborn wrinkles, brighten dark spots, decongest and firm your skin - without irritation. Pairing these products correctly can transform your skincare routine.
AHA:
Sleep Glycolic is a perfect at-home peel that delivers fast results overnight, to reveal a visibly smoother and glowing complexion, with a more even tone and texture.
PHA:
A gentle daily toner, the Press & Glow is formulated with the power of PHA to remove dead surface skin cells and reveal a smoother skin texture.
Retinoids are the umbrella term for all vitamin A molecules in their different forms. Praised for their youth-renewing benefits, retinoids help to accelerate skin cell turnover and support collagen. At Medik8, we use 3 main types of retinoids; retinol, retinaldehyde (retinal) and retinyl retinoate. All our vitamin A formulas are infused with Time Release and stabilisation technologies to gradually infuse the active into the skin throughout the night for minimal irritation.
Before introducing powerful actives like acids and retinol into your routine, consult a board-certified dermatologist. They can provide personalised advice based on your skin type, concerns, and goals, ensuring that you use these ingredients safely and effectively.
If you aren’t quite sure where to start, at Medik8 we can help you build your own bespoke regime suited to you and your skin needs.
We believe the key to success with any skincare routine is patience and consistency, coupled with a keen awareness of your skin's needs and reactions. By thoughtfully integrating acids and retinol into your skincare routine and seeking professional guidance, you can achieve a balanced, healthy complexion without compromising your skin’s overall health.
At Medik8 we have unlocked the secret to glowing, youthful skin with our breakthrough CSA Philosophy which is as simple as using vitamin C during the day and vitamin A (retinoids) at night.
What should I use for my skin type
Best practices for using acids and retinol depend on your specific skin type and concerns.
AHAs, such as glycolic acid and lactic acid, are excellent for hydrating and exfoliating the skin, enhancing its radiance. They are particularly effective for resurfacing and rejuvenating normal, dry, or mature skin. For those with sensitive, oily, or congested skin, BHAs are ideal as they clear deep pores, reduce inflammation, and prevent acne or breakouts.
Retinoids are beneficial for clearing acne and are also powerful anti-ageing ingredients. Suitable for all skin types, the strength of retinoid you choose should align with the specific skin concern you aim to address.
Normal to Dry Skin:
Use AHAs to gently exfoliate and hydrate. They help to remove dead skin cells and boost skin radiance.
Oily and Congested Skin:
BHAs are ideal for penetrating deep into the pores, reducing oiliness and preventing blemishes and breakouts.
Sensitive Skin:
Start with a gentle retinoid like retinaldehyde and a mild PHA exfoliant to avoid irritation while still benefiting from exfoliation.
Combination Skin:
Use a retinoid for overall skin improvement and a BHA product for oily areas prone to breakouts.
Mature Skin:
Opt for a retinoid to address signs of ageing, and pair it with an AHA exfoliant to maintain a youthful glow.
If you can’t decide which skin type you fall into or you think your skin fits more than one category, try one product for a few weeks to see what results you get.
Women who are pregnant or breastfeeding may be advised to use hydroxy acids over retinoids or bakuchiol, a plant-based alternative to vitamin A. For some, hydroxy acids may cause irritation and dryness. In this case, using retinoids may be more beneficial for the skin.
Tips for combining AHAs, BHAs and retinol
What to do if your skin becomes irritated
Sometimes irritation may occur when using potent active ingredients like AHAs, BHAs, and retinoids. If you start to feel sensitivity or irritation on your skin, it’s important to take immediate action to prevent further damage. Here’s what to do:
To takeaway
In conclusion, acids and retinoids play pivotal roles in skincare, each offering unique benefits that can transform your skin. AHAs, BHAs, and PHAs provide effective exfoliation, helping to rejuvenate the skin and address specific concerns like acne, congestion, and dullness. Retinoids, particularly retinAL, are powerful anti-ageing ingredients that promote cell turnover and collagen production, delivering visible improvements in skin texture and tone.
When used together, these ingredients can create a synergistic effect, maximising their benefits. However, it's crucial to introduce them slowly and monitor your skin's response to avoid irritation. Medik8’s advanced formulations ensure that these potent ingredients can be used safely and effectively in combination.
*G. Siegenthaler et al., Retinol and retinal metabolism, Biochemical Journal, 1990, 268, pp 371-378
FAQs
Yes, retinol can be used with acids, but it's important to approach this combination with care. While both retinol and exfoliating acids (like AHAs and BHAs) provide beneficial results for skin texture and clarity, they can be potent when used together. For those with sensitive skin, it's best to introduce them gradually to avoid irritation.
Use acids in the morning and retinol at night to maximise their benefits and minimise irritation.
PHAs are the most gentle acids and can work well with retinol, offering exfoliation without significant irritation.
Apply glycolic acid in the morning and retinol at night. We advise avoiding using them in the same routine unless you have built up a tolerance to both ingredients separately.
Yes, but use them on alternate nights to prevent over-exfoliation and irritation.
Yes, as retinol is not an exfoliant. Occasional exfoliation can help remove dead skin cells, but be cautious and avoid over-exfoliating.
Avoid using retinol, benzoyl peroxide, and other strong actives with AHA & BHA to prevent irritation.
Avoid using strong acids, benzoyl peroxide, and vitamin C with retinol in the same routine.
Yes, but use them on alternate nights to reduce the risk of irritation and enhance their benefits.
Radhika Sen
Radhika Sen is a skincare enthusiast and beauty writer. She's always on the lookout for a stellar serum and moisturiser combination, topped by a sunscreen that protects and primes. Her idea of self care is to pop on a face mask, light a scented candle and call it an early night.