15 skincare ingredients, decoded.

Effective concentration

2-5%

What it does

Reduces oil, fades dark marks, repairs barrier, anti-inflammatory. One of the few ingredients that does multiple things well without irritation.

What can go wrong

10%+ concentrations can cause tingling and redness for some people. Higher is not better. 5% has the most research behind it.

Pairs with

Almost everything. The 'can't use with vitamin C' myth is debunked.

Effective concentration

0.1-0.5% (OTC), 0.025-0.1% tretinoin (Rx)

What it does

Increases cell turnover, unclogs pores, reduces fine lines, fades pigmentation. The single most researched anti-aging ingredient.

What can go wrong

Causes purging (4-6 weeks), dryness, and sun sensitivity. Start low (0.1%), use 2x/week, always with sunscreen. Do not self-prescribe tretinoin. See a derm.

Pairs with

Moisturiser (buffer), sunscreen (mandatory). Avoid layering with AHA/BHA on the same night.

Effective concentration

0.5-2%

What it does

Oil-soluble, so it gets inside pores and dissolves clogs. Best OTC ingredient for blackheads and mild acne.

What can go wrong

Over-use strips your barrier. Every other night is enough for most people. If skin feels tight or dry, you're using too much.

Pairs with

Gentle cleanser, moisturiser. Don't layer with other exfoliants (AHA, retinol) on the same night.

Effective concentration

10% (OTC), 15-20% (Rx)

What it does

Anti-bacterial, anti-inflammatory, reduces pigmentation. One of the few actives safe during pregnancy. Over 50% of subjects had no PIH remaining after 16 weeks at 15%.

What can go wrong

Can sting for the first few uses. Prescription strength (Aziderm 20%, ~₹300) works faster than OTC versions.

Pairs with

Niacinamide, sunscreen. Good alternative to hydroquinone for pigmentation.

Effective concentration

Not standardised (look for it in top 5-10 ingredients)

What it does

Your skin barrier is made of ceramides. When the barrier is damaged (from over-exfoliating, harsh weather, too many actives), ceramide moisturisers help rebuild it.

What can go wrong

Not a treatment for acne or pigmentation. It's a support ingredient. If your barrier is healthy, you don't need extra ceramides.

Pairs with

Everything. Ceramide moisturisers make other actives work better because they keep the barrier intact.

Effective concentration

10-20% (LAA), 2-5% (derivatives)

What it does

Antioxidant, mild brightening, some collagen support. L-ascorbic acid is the most researched form but also the most unstable.

What can go wrong

Oxidises fast (turns yellow/brown). Indian heat and humidity accelerate this. Derivatives (ethyl ascorbic acid) are more stable but potentially less potent. Brightening effect is subtle, not dramatic.

Pairs with

Sunscreen (mandatory). Vitamin E and ferulic acid stabilise it. Use in AM.

Effective concentration

0.1-2%

What it does

Holds up to 1000x its weight in water. Sounds impressive. In practice, it hydrates the surface temporarily. Good for dehydrated skin, does very little for dry skin (which needs oil, not water).

What can go wrong

In dry/AC environments, HA can actually pull moisture OUT of your skin instead of from the air. Always seal with a moisturiser on top. If you live in a dry climate, HA without a moisturiser on top can make things worse.

Pairs with

Always layer moisturiser on top. Apply on damp skin.

Effective concentration

Varies widely

What it does

Signal skin to produce more collagen. Research is promising but limited. Most studies are small, short-term, or funded by peptide manufacturers.

What can go wrong

Expensive ingredient, modest results. If you're choosing between peptides and retinol for anti-aging, retinol has 50+ years of research. Peptides have a few dozen studies.

Pairs with

Moisturiser, sunscreen. Won't conflict with other actives.

Effective concentration

5-10% (leave-on), up to 30% (peels, professional only)

What it does

Exfoliates the skin surface. Dissolves dead cells. Improves texture and dullness. Water-soluble (works on the surface, not inside pores like BHA).

What can go wrong

Increases sun sensitivity significantly. Using glycolic without sunscreen will cause more pigmentation, not less. Start with 5%, 2x/week max. Chemical peels above 20% should only be done by professionals.

Pairs with

Sunscreen (non-negotiable). Moisturiser. Never layer with retinol or other acids on the same night.

Effective concentration

2.5% (spot treatment)

What it does

Kills C. acnes bacteria. The most effective OTC antibacterial for acne. 2.5% is as effective as 10% with less irritation (three studies confirm this).

What can go wrong

Extremely drying if used all over the face. Use as spot treatment ONLY on active pimples. Bleaches fabric (pillowcases, towels). Can damage your barrier if overused.

Pairs with

Moisturiser (mandatory after). Don't combine with retinol, AHA, or BHA on the same night.

Effective concentration

2% (OTC), 4% (Rx)

What it does

The gold standard for treating hyperpigmentation and melasma. Works by inhibiting tyrosinase (the enzyme that produces melanin). Effective but controversial.

What can go wrong

Not for long-term use (max 3-4 months at a time). Can cause ochronosis (paradoxical darkening) with prolonged use. Prescription only for 4%. Banned in some countries for OTC use. Always use under derm supervision.

Pairs with

Sunscreen (absolutely mandatory). Often prescribed with tretinoin and a steroid (Kligman's formula).

Effective concentration

2-5% (topical)

What it does

Newer ingredient for pigmentation. Early studies show it works for melasma and PIH, with fewer side effects than hydroquinone. A combination serum with niacinamide + tranexamic acid + vitamin C performed comparably to 4% hydroquinone in one study.

What can go wrong

Most research is recent and small-scale. Long-term safety data for topical use is still limited. Promising but not yet proven at the level of niacinamide or azelaic acid.

Pairs with

Niacinamide, sunscreen. Generally well-tolerated.

Effective concentration

96% in the famous CosRX essence

What it does

Hydrating, soothing, and helps with skin texture. The CosRX Advanced Snail 96 Mucin Power Essence is one of the most popular K-beauty products globally. Contains glycoproteins, hyaluronic acid, and glycolic acid naturally. Studies show wound-healing and hydrating properties.

What can go wrong

Most research is on wound healing, not cosmetic anti-aging. The 'snail' factor is a marketing hook. It works as a hydrating essence, but so do many other products without the snail. If the texture doesn't bother you and your skin likes it, it's fine. Not a miracle ingredient.

Pairs with

Layer under moisturiser. Works well with niacinamide. Use in the serum step of your routine.

Effective concentration

Pure oil or in formulation

What it does

A lightweight oil that mimics your skin's natural sebum. Non-comedogenic for most people. Good for sealing in moisture without feeling heavy.

What can go wrong

It's a moisturising oil, not a treatment. Won't fix acne, pigmentation, or aging. Marketing overstates its benefits. It's just a nice-feeling oil.

Pairs with

Layer over water-based serums. Works as a final step before sunscreen.

Effective concentration

0.5-2%

What it does

Plant-derived ingredient marketed as a gentler retinol alternative. One study showed comparable results to 0.5% retinol for wrinkles and pigmentation after 12 weeks.

What can go wrong

One study is not enough to call it equivalent to retinol (which has decades of research). If you can tolerate retinol, use retinol. If you can't (pregnancy, extreme sensitivity), bakuchiol is a reasonable alternative with less evidence.

Pairs with

Moisturiser, sunscreen. Safe during pregnancy (unlike retinol).