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How to mix your skincare ingredients

By Georgia Seago
3rd March 2022

Test tubes in beaker

You’ll find a lot of people on social media calling themselves ‘skincare gurus’ these days. They tend to be proponents of lengthy routines comprising multiple products containing myriad active ingredients, with a focus on getting the elusive “glow” everyone so badly wants to achieve.

The problem with taking advice from these people is that they aren’t skin professionals and have no experience of treating skin other than their own. If you follow their advice, you can end up spending a lot of money on products that may not suit you, or which shouldn’t be used together, which may end up sensitising your skin and creating further issues.

Here’s a list of the most common types of active ingredients you’ll hear people talking about  – along with advice on how to use them together so as not to irritate  your skin. Better yet, book in with an expert cosmetic doctor or facialist to find out exactly what you should and shouldn’t be doing for your particular skincare concerns.

AHAs (alpha-hydroxy acids) – glycolic, lactic, mandelic, malic and citric acids

  • Exfoliate skin by encouraging the shedding of dead skin cells.
  • Improve barrier function by improving skin hydration.
  • Water-soluble, so they stay at and work on the skin’s surface.
  • Be cautious when combining with retinol because both speed up cell turnover – don’t use together in the same night routine. Try alternating nights if your skin can tolerate both products and you find them effective.

TTG recommends: Alpha H Liquid Gold

BHAs (beta-hydroxy acids) – salicylic acid

  • Like AHAs, BHAs exfoliate skin by dissolving the bonds that tether dead skin cells to the skin’s surface.
  • Anti-bacterial and anti-inflammatory – good choice for oily skin and breakouts
  • Oil soluble  – so can penetrate into blocked pores to help clear the blockage and calm inflamed spots
  • Improves overall skin texture with generally less irritation than AHAs
  • Be careful about mixing BHAs with AHAs. I wouldn’t do this unless you’ve been advised to by a skin professional.

TTG recommends: Alpha H Clear Skin Tonic

PHAs (poly-hydroxy acids)– lactobionic acid and gluconolactone

  • Similar to AHAs but shallower penetration, so they’re gentler on the skin.
  • Safe to use alongside retinol – gluconolactone is an antioxidant with soothing and hydrating properties that aids penetration of retinol.

Hyaluronic acid (HA)

  • A water-binding molecule that occurs naturally in our bodies.
  • Hydrates skin by drawing moisture into the skin.
  • Use moisturiser over HA to seal the hydration into the skin.
  • Safe for all skins and works well alongside other acids and actives.

TTG recommends: Medik8 Hydr8 B5 Skin Rehydration Serum


  • Retinol is part of a family of ingredients called retinoids, which are all derived from vitamin A.
  • Retinol is a weaker cousin of prescription-only retinoic acid (tretinoin), and you find it in many over-the-counter skincare products.
  • Multiple skin-health benefits: retinol stimulates cell renewal and helps new collagen and elastin to develop. Normalises oil-production, so oily skin becomes less oily. Improves skin hydration. Softens pigmentation marks.
  • How effective retinol is depends on the percentage of retinol a product contains, along with the formulation.
  • Start slowly with retinol. Use it every second or third night to acclimatise your skin and check tolerance. Apply moisturiser afterwards, to help counteract any dryness. If your skin looks red and irritated, wait until it recovers before using again.
  • Works well alongside other acids in a routine but should be applied at different times of the day – e.g., L-ascorbic in the morning and retinol at night
  • Daily sunscreen is vital as retinol makes skin more sensitive to the sun.

TTG recommends: Medik8 3TR

L-ascorbic acid (vitamin C)

  • Generally, the best form of vitamin C to use in skincare as it’s the most bio-available
  • Helps strengthen the skin against pollution and UV light.
  • Reduces the appearance of hyperpigmentation and age spots so skin looks brighter.
  • An antioxidant, so protects against oxidative stress – therefore, usually applied in the morning
  • Helps support the formation of new collagen in the skin.
  • Be cautious when layering directly with AHAs or BHAs. Pick one to start using first and gradually introduce the other every other day. Or start by using one or the other in a wash-off format, e.g., in your cleanser.

TTG recommends: Belgravia Dermatology Potent C


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