The Truth About Skincare Acids: What Actually Works
A clinician's guide to hyaluronic acid, salicylic acid, glycolic acid, vitamin C and azelaic acid — what the evidence actually says.
Book a Consultation"I've had several appointments with Dr Etienne Raffner now. He's a great doctor as he always listens to my concerns and gives plenty of advice and encouragement."
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— Google Review"I felt completely confident in Dr Raffner's hands. His knowledge as a maxillofacial surgeon makes such a difference to the quality of results."
— Google Review"I've had several appointments with Dr Etienne Raffner now. He's a great doctor as he always listens to my concerns and gives plenty of advice and encouragement."
— Google Review"Dr Raffner is an incredibly skilled and knowledgeable surgeon. His attention to detail and care for his patients is second to none."
— Google Review"Absolutely fantastic experience with Dr Raffner. He made me feel completely at ease and the results are beautiful and natural."
— Google Review"Dr Etienne is so professional and reassuring. He took the time to explain everything in detail. I couldn't be happier with the results."
— Google Review"Outstanding care from Dr Raffner. You can really tell he has a surgical background — so precise and thorough. Highly recommend."
— Google Review"The most natural-looking results I've ever had. Dr Raffner's medical expertise really shows. He has a wonderful, calming manner."
— Google Review"I felt completely confident in Dr Raffner's hands. His knowledge as a maxillofacial surgeon makes such a difference to the quality of results."
— Google ReviewWhat Are Skincare Acids?
At EJR Aesthetics in Chichester and Haywards Heath, we regularly see patients who have spent hundreds of pounds on skincare with little to show for it — not because skincare doesn't work, but because most people are using the wrong products, at the wrong concentrations, in the wrong way.
Skincare acids are a class of active ingredient that — when correctly formulated and used — have the strongest evidence base in cosmetic dermatology. They work by exfoliating, hydrating, stimulating collagen synthesis, treating acne, and reducing pigmentation. But formulation, concentration, and usage all determine whether you get results — or waste money.
The Key Skincare Acids: What the Evidence Says
Hyaluronic Acid
HydrationBest for: Dry, dehydrated, ageing skin
✓ Works when
✗ Doesn't work when
The Science
A 2021 study in the Journal of Cosmetic Dermatology confirmed that multi-weight hyaluronic acid significantly outperforms single-weight formulations in improving skin hydration at multiple depths.
Dr Raffner Says
"Hyaluronic acid is genuinely effective — but formulation matters enormously. Many popular budget products use only one molecular weight, which limits results. At the clinic, we recommend medical-grade formulations that work at multiple skin depths."
Salicylic Acid
Acne TreatmentBest for: Oily, acne-prone, congested skin
✓ Works when
✗ Doesn't work when
The Science
Salicylic acid is a beta-hydroxy acid (BHA) — oil-soluble, which means it penetrates into pores to dissolve the keratin plugs responsible for blackheads and whiteheads. Research in Dermatology & Therapy (2019) confirmed its efficacy as a leave-on treatment for mild-to-moderate acne.
Dr Raffner Says
"The key with salicylic acid is leave-on application at adequate concentration. Many popular wash-off products from high-street brands simply don't have sufficient contact time to work properly. We recommend leave-on formulations at 1–2% for patients with acne-prone skin."
Glycolic Acid
Anti-Ageing & BrighteningBest for: Fine lines, dull skin, pigmentation
✓ Works when
✗ Doesn't work when
The Science
Glycolic acid is the smallest alpha-hydroxy acid (AHA), which allows it to penetrate skin most effectively. A landmark study in the Archives of Dermatology demonstrated that glycolic acid at therapeutic concentrations stimulates collagen synthesis and significantly improves skin texture with consistent use.
Dr Raffner Says
"Glycolic acid is one of the most evidence-based ingredients we have for skin rejuvenation. But it needs to be at the right concentration. Many products from high-street brands are formulated mildly — suitable for maintenance but not transformation. For real results, a clinical-grade regimen or professional peel is often required."
Vitamin C (L-Ascorbic Acid)
Brightening & AntioxidantBest for: Dull skin, pigmentation, UV protection
✓ Works when
✗ Doesn't work when
The Science
L-ascorbic acid is the only form of vitamin C with robust evidence for skin brightening and collagen stimulation. Research published in the Journal of the American Academy of Dermatology confirmed its efficacy — but noted that stability and concentration are critical to outcomes.
Dr Raffner Says
"Vitamin C is brilliant — but it's notoriously unstable. A lot of products oxidise before you've even made a dent in the bottle. We recommend properly packaged, stable formulations at 15–20% L-ascorbic acid. Obagi Professional-C is our recommendation for patients who want genuine brightening results."
Azelaic Acid
Acne & PigmentationBest for: Rosacea, acne, melasma
✓ Works when
✗ Doesn't work when
The Science
Azelaic acid works by inhibiting tyrosinase (reducing pigmentation), killing acne-causing bacteria, and reducing inflammation. A Cochrane review confirmed its efficacy for both acne and rosacea, making it one of the most versatile evidence-based actives available.
Dr Raffner Says
"Azelaic acid is underrated. It's one of the safest actives available — suitable even during pregnancy — and genuinely effective for rosacea, pigmentation and acne. It's a staple in many of the personalised skin programmes we create for patients."
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