What is acid cycling and is it damaging to midlife skin?

I have noticed a worrying trend towards women getting carried away, shall we say, with acid cycling for skin exfoliation.

What is acid cycling?

Acid cycling, also known as skin cycling, is a skincare approach where exfoliating acids are used on a rotating schedule rather than daily, with the intention of stimulating renewal while allowing recovery in between applications. In theory, it’s not a bad idea. Different acids have different have different strengths and so impact the skin differently. Acid cycling as a routine was designed to be a more disciplined, kinder alternative to constant exfoliation. You might use a retinol serum on one night, for example, then use a gentler acid the next night, and then have two nights of pure pamper skincare, with no thought of exfoliation. 

Where is acid cycling going wrong?

In practice, the term has drifted far from its original logic and I think this is very much down to a lack of understanding about the differences between the various acids we can use -  retinoids, AHAs, PHAs and BHAs; a lack of understanding about how skin actually works and a somewhat bonkers, in my opinion, obsession with ‘no pain, no gain’. Skin that stings, flakes or burns is seen as proof that the skin cycling routine is working.

This means women are using multiple acids across the week and giving their skin minimal recovery time in a (mistaken) belief that as long as acids are not used every single night, the skin is being respected.

Clinically, acids are not neutral tools. The clue is in the name. Alpha hydroxy acids, beta hydroxy acids and polyhydroxy acids all send biological signals to the skin. They influence skin cell shedding, inflammation pathways and barrier lipid organisation. Every time you apply an acid to your skin it will have an impact – repeat applications result in stressed skin, unable to keep up with the change being inflicted upon it.

The mistaken assumption that the way to achieve more youthful skin is to encourage it to shed and renew as it did when we were actually young can actually cause long-term damage, not to mention hot, sore, flaking skin that has no relation to the soft, glowing, plump skin you are seeking.

How do we do healthy acid cycling?

The first thing we need to understand is that mature skin can never, ever, behave like young skin again. In our thirties, forties and fifties, epidermal turnover slows more and more; keratinocyte differentiation takes longer (keratinocytes are the main skin cells of the epidermis. As they age they ‘differentiate’, i.e. change, into corneocytes, the outermost layer of the epidermis.). Skin barrier lipids take longer to produce and fill the gaps around the corneocytes, meaning it’s easy to compromise your skin barrier, and inflammation takes longer to settle. This is not something you are doing wrong; this is biology. When you override your natural biological processes with constant exfoliation, the skin does not become younger, it becomes stressed.

A healthy skin cycling routine

The acid cycling routine best for you depends upon how sensitive or damaged your skin is. If your skin barrier is compromised, you need to go very, very gently, working first on rebuilding your skin barrier. If you do not struggle with any inflammation, or outbreaks, you can ramp it up a little - but ladies, nobody ever needs an at-home peel. Ever.

For robust skin with a healthy skin barrier:

Night one: use an AHA, such as glycolic acid or lactic acid, in serum form overnight, then gently wash away next day. These will lift away dead skin cells and enable your skincare to have greater impact upon your epidermis.

Night two: after a gentle cleanse, use a retinol serum, or if you have very sensitive skin, a natural alternative such as bakuchiol, overnight. Retinoids prompt skin cells (keratinocytes) to proliferate faster, pushing old cells to the surface and shedding them more quickly, revealing newer, healthier cells underneath. By using the AHA the night before, you clear a path, as it were, for the retinol to penetrate more deeply into the epidermis and so do what it’s designed to do.

Nights three and four: do not apply any acids. Simply treat your skin to an overnight pamper of a deeply hydrating hyaluronic acid serum and supporting moisturiser.

Your SkinGoal options: my Serum L contains two AHAs, glycolic and salicylic acid, both of which work to gently exfoliate and clear pores. On night two, my Power R1% will get to work, helping boost your skincell turnover and smooth skin’s texture. On nights three and four, use my Power HA hyaluronic acid serum followed by my gorgeous Cream Lift, which contains no acids, but instead contains highly effective and hydrating high-grade peptides, plant stem cells and hyaluronic acid to give your skin a luxurious experience while helping support skincell activity and barrier repair. In the morning use a gentle cleanser, such as my Prep Cleanse.

For sensitive skin:

Night one: Power B. It’s gentle but effective, containing gentler actives that exfoliate skin with less aggression than AHAs. It contains kojic acid, a gentle AHA that actually targets skin pigmentation as well as gently exfoliating and azalaic acid, too, which is a gentle acid that has potent anti-inflammatory, antibacterial, and exfoliating properties. 

I created Serum B to address skin pigmentation rather than skin exfoliation, but for sensitive skin it’s a great alternative. Or seek out a PHA-based serum. PHAs exfoliate too, but as they have larger molecules than AHAs don’t penetrate skin so deeply and are less likely to cause inflammation.

Night two: I’d recommend if you have sensitive skin to stay away from retinol serums. My Cream Revive night cream actually contains bakuchiol, a natural alternative to retinol, that will over time help exfoliate skin and improve cell turnover without the risk of irritation of retinol. If you want to bump up a level from your Serum B, then Serum L is a good option. 

Nights three and four - pamper time! 

An alternative to overnight skin cycling

Your skin works hard overnight. It casts off, or attempts to, dead skin cells, addresses inflammation and produces the oils, or lipids, that make your skin barrier strong. In the mornings, a good cleanse with a mild exfoliator is something you can do every day. I developed my Prep range for this very purpose. 

Prep Wash contains glycolic and citric acid (both AHAs) in a light concentration, sufficient to lift away skin cell debris and excess oils without causing irritation. You can use this every day. 

For days when skin is feeling a bit dry and even rough (you know that tight, dull feeling you get sometimes!) then Prep Power contains clinical strength formulations of three AHAs -  glycolic acid to strip away dead skin cells; salicylic acid to target oil buildup in your pores, which helps prevent breakouts and calms inflammation; and lactic acid, which is not only a gentle exfoliator, but a humectant, drawing moisture into your skin for enhanced hydration.

I have built a routine around both these Prep products and a single weekly overnight with Serum R1%. I have learned how my skin works, what it needs and how to maximise my own body’s ability to do what it’s designed to do by helping it along with the right product at the right time.

This is intelligent skin cycling - if you go slowly, one step at a time, to work your way up to a regular acid cycling routine, you will find you achieve that glowing, healthy-looking skin you seek with none of the pain you really don’t need.

If you have more questions, try my (I don’t mind saying) fabulous Penny AI skin consultation on the website. She’s pretty darn smart and can help you decide where to start and what’s best for you.

Love, Penny x