Reference guide · ingredients, compatibility, HSA/FSA eligibility, and where to buy at Ulta and Walgreens · tan to deep skin tone focus
HSA / FSA eligibility note: Eligibility is determined by the IRS and your specific plan administrator — rules can change at any time. The guidance below is based on current IRS Publication 969 and CARES Act rules. Always confirm with your plan before purchasing. Products that treat a diagnosed medical condition (acne, rosacea, eczema) are more likely to qualify than those used for cosmetic purposes only. A Letter of Medical Necessity from a dermatologist can unlock eligibility for borderline products.
Click any cell to see the full explanation. Covers the 11 most commonly combined skincare actives.
✓ Safe to combine
⚠ Separate timing or caution
✕ Avoid — same session
Click any cell in the matrix to see compatibility details.
AM vs PM — what goes when
☀ Morning (AM)
Gentle non-active cleanser
Vitamin C serum (before SPF — boosts ultraviolet protection)
Niacinamide (AM or PM)
Tranexamic acid (AM or PM)
Azelaic acid (AM or PM — photostable)
Hyaluronic acid serum (on damp skin)
Ceramide moisturiser (seal within 60 sec)
Benzoyl peroxide — spot treatment only
SPF 30+ — always the final AM step
🌙 Night (PM)
Gentle cleanser (double cleanse if SPF was worn)
Retinol or Tretinoin (PM only — light degrades it)
Salicylic acid — on non-retinol nights only
Glycolic or lactic acid — on non-retinol nights only
Niacinamide (AM or PM)
Tranexamic acid (AM or PM)
Hyaluronic acid serum
Ceramide moisturiser — always the final PM step
Layering order — thinnest to thickest
☀ AM Layering Order
1
Cleanser
Rinse off — does not stay on skin
2
Vitamin C serum
Thinnest, most acidic — goes first
3
Niacinamide or tranexamic acid serum
Water-based serums after vitamin C
4
Hyaluronic acid serum
On slightly damp skin — seal within 60 seconds
5
Ceramide moisturiser
Seals hyaluronic acid and protects the barrier
6
Squalane or face oil (optional)
Heavier than cream — goes on top if using
7
SPF — always final step
Never layer anything on top of sunscreen
🌙 PM Layering Order
1
Oil or balm cleanser (if SPF was worn)
First cleanse — removes sunscreen and makeup
2
Gentle gel or cream cleanser
Second cleanse — cleans the skin itself
3
Exfoliating acid OR retinol (never both same night)
On dry skin — wait 10–20 min after cleansing for retinol
4
Niacinamide or brightening serum
After active absorbs — 5–10 min wait after acids
5
Hyaluronic acid serum (optional PM)
On slightly damp skin
6
Ceramide moisturiser — always final step
Seals everything in overnight
Golden rules
✕ Never do these
—Retinol + benzoyl peroxide same session (BP destroys retinol)
—Retinol + AHA or salicylic acid same night
—Vitamin C + benzoyl peroxide same session
—Two exfoliating acids on the same night
—Retinol on damp skin — always fully dry first
—Hyaluronic acid without sealing immediately with moisturiser
—Adding a new active while skin is flaring or barrier is damaged
✓ Always do these
—SPF every morning — including indoors near windows
—Introduce one new active at a time — wait 2–4 weeks
—Patch test any new product on inner arm for 24–48 hours
—Start retinol every 3rd night and build slowly over months
—Seal hyaluronic acid within 60 seconds with ceramide cream
—Wait for skin to be fully dry before applying retinol
—Return to barrier repair any time skin flakes or burns
Specific notes for tan to deep skin tones
Post-inflammatory hyperpigmentation is more stubborn on deeper skin tones
More melanin is produced in response to any skin injury. Dark marks form more easily and take longer to fade. Consistent SPF is the single most important factor. Best ingredients: niacinamide, tranexamic acid, azelaic acid, alpha arbutin. Mandelic acid is the safest AHA — largest molecule, slowest penetration, lowest hyperpigmentation trigger risk.
Avoid on deeper skin tones without medical supervision
High-concentration glycolic acid above 10% can trigger rebound hyperpigmentation if overused. High-strength hydroquinone used long-term can cause paradoxical darkening. Physical scrubs and high-friction tools cause trauma that leads to new dark spots.
Best ingredients specifically for tan to deep skin tones
Niacinamide 5% · Tranexamic acid · Azelaic acid 10–15% · Mandelic acid · Alpha arbutin · Vitamin C in stable forms (ascorbyl glucoside, magnesium ascorbyl phosphate) · SPF every single day.
When to stop actives and return to barrier repair
⚠Skin is burning, stinging, or raw — stop all actives immediately
⚠Visible peeling or flaking that does not resolve within a few days
⚠Dark spots that appear to be getting darker rather than fading
⚠Starting a new prescription that affects skin (antibiotics, hormonal changes)
⚠Before and after any in-office treatment (chemical peel, laser, microneedling)
⚠When unsure if a reaction is purging vs irritation — when in doubt, pause