Diamond Retinal 25

Diamond Retinal 25 is the apex of Cyrène's Diamond Retinal series — a professional-strength night serum delivering 0.25% retinaldehyde via an enhanced phospholipid liposomal system, in a distinctly premium formulation that sets it apart from every other product in the range. At this concentration, retinal's single-step conversion to retinoic acid operates at a speed and receptor activation intensity that places this formula firmly at the clinical boundary of non-prescription retinoid therapy.

Aqua, Caprylic/Capric Triglyceride, Glycerin, Glyceryl Stearate, Squalane, Cetyl Stearyl Alcohol, Phospholipids, Ascorbic Acid, 3-O-Ethyl Ascorbic Acid, Niacinamide, Retinal, Sodium Hyaluronate, Sodium Polyacrylate, Phenoxyethanol, Acetyl Hexapeptide-8, Palmitoyl Tripeptide-5, Ceramide NP, Ceramide AP, Ceramide EOP, Phytosphingosine, Sodium Lauroyl Lactylate, Caprylyl Glycol, Dimethicone/Vinyl Dimethicone Crosspolymer, Beta-Glucan, Xanthan Gum, Dimethicone, Ethylhexylglycerin, Centella Asiatica Extract, Cholesterol, Cyclopentasiloxane, Tocopherol

Aqua, Caprylic/Capric Triglyceride, Glycerin, Glyceryl Stearate, Squalane, Cetyl Stearyl Alcohol, Phospholipids, Ascorbic Acid, 3-O-Ethyl Ascorbic Acid, Niacinamide, Retinal, Sodium Hyaluronate, Sodium Polyacrylate, Phenoxyethanol, Acetyl Hexapeptide-8, Palmitoyl Tripeptide-5, Ceramide NP, Ceramide AP, Ceramide EOP, Phytosphingosine, Sodium Lauroyl Lactylate, Caprylyl Glycol, Dimethicone/Vinyl Dimethicone Crosspolymer, Beta-Glucan, Xanthan Gum, Dimethicone, Ethylhexylglycerin, Centella Asiatica Extract, Cholesterol, Cyclopentasiloxane, Tocopherol

When to Use: PM only. Retinoic acid conversion is an overnight process. SPF the following morning is mandatory and non-negotiable at this retinal strength.

Application Steps:

Cleanse and pat skin completely dry — applying to damp skin at this concentration significantly elevates irritation risk
Apply Cyrène Hyaluronic Acid Intensifier first — allow to absorb fully before proceeding
Dispense 3–4 drops onto fingertips
Press gently and evenly across the face and neck; avoid the immediate eye orbit and lip margin
Allow 60–90 seconds for the silicone-based formula to settle and absorb
Seal with Cyrène CeraPep Barrier Support Moisturiser

Re-introduction Frequency — Mandatory Even For DR10 Users:

Weeks 1–2: Two applications per week
Weeks 3–4: Three to four applications per week
Week 5 onwards: Five to seven applications per week, building to nightly as tolerated

Pro Clinic Tip: At 0.25% retinal, the retinoic acid-driven purging phase — temporary increase in surface cell shedding and initial skin adjustment — may be more pronounced than at any earlier step in the series. This is a normal and expected phase of intensive retinoid introduction, not a sign of incompatibility. Maintain the protocol, sustain barrier moisturisation, and avoid introducing any new actives during the first six weeks.

Pairs Best With

Cyrène CeraPep Barrier Support Moisturiser — Essential at this retinal concentration. Apply as the final PM step. Even with the ceramide complex within the formula, an occlusive barrier-supporting moisturiser applied over Diamond Retinal 25 compounds the barrier protection and sustains optimal hydration levels through intensive overnight turnover.
Cyrène Hyaluronic Acid Intensifier — Apply first on slightly damp skin. At 0.25% retinal, transepidermal water loss is at its highest within the series; layered hyaluronic acid establishes an external hydration reservoir that works alongside the formula's elevated Sodium Hyaluronate.
Cyrène Invisible Physical Sunscreen SPF50 — Absolutely non-negotiable the following morning. At 0.25% retinal, photosensitivity is at its greatest; unprotected UV exposure directly undermines retinoic acid-driven renewal and risks hyperpigmentation.

Do Not Combine In The Same Routine

AHAs & BHAs (Glycolic, Lactic, Salicylic Acid) — At 0.25% retinal, combining any chemical exfoliant in the same routine risks acute retinoid dermatitis. Strictly alternate evenings — no exceptions.
L-Ascorbic Acid Vitamin C — The dual Vitamin C system within the formula provides sufficient antioxidant and brightening activity. Additional L-Ascorbic Acid at night is unnecessary.
Benzoyl Peroxide — Immediately oxidises and destroys retinal. Do not combine under any circumstances.
Any Other Retinoid Product — Do not layer additional retinol, retinal, or retinyl ester products in the same PM routine.
Physical or Chemical Facial Exfoliation Treatments — Avoid microdermabrasion, dermaplaning, chemical peels, or laser treatments in the same period without professional guidance.

What is the strongest retinal serum available without a prescription?
Diamond Retinal 25 contains 0.25% retinaldehyde — the highest concentration available in the Cyrène Diamond Retinal series and among the highest concentrations of encapsulated retinal available in the non-prescription skincare market. Medik8's highest consumer retinal product, Crystal Retinal 24, contains 0.2% retinaldehyde. At 0.25%, Diamond Retinal 25 exceeds this threshold within a professional-grade, phospholipid liposomally encapsulated delivery system designed to sustain both efficacy and tolerability at this concentration.

Who is Diamond Retinal 25 designed for?
Diamond Retinal 25 is designed for three groups of users. First, those who have completed the Diamond Retinal progression — establishing consistent nightly tolerance across DR1, DR3, DR5, and DR10 — and are ready for the series' highest concentration. Second, those who have used prescription retinoids (tretinoin, adapalene) and are seeking a non-prescription alternative that maintains meaningful retinoic acid-adjacent activity between treatment cycles or after completing a prescription course. Third, skincare professionals seeking a professional-grade retinal product for in-clinic recommendation or retail. It is not suitable as a first retinoid.

What makes Diamond Retinal 25 different from the rest of the Diamond Retinal series?
Diamond Retinal 25 differs from Diamond Retinal 1 through 10 in four significant ways. First, retinal concentration: 0.25% versus a maximum of 0.1% in DR10. Second, peptide system: Acetyl Hexapeptide-8 (Argireline) and Palmitoyl Tripeptide-5 replace Matrixyl 3000, targeting both neuromuscular expression line relaxation and TGF-β-mediated collagen stimulation. Third, barrier architecture: a full five-component ceramide complex returns to the formula, essential for sustaining skin integrity under intensive retinoic acid-driven turnover. Fourth, packaging: the premium airless silver serum bottle is architecturally distinct from the Diamond Retinal series, reflecting the professional-grade nature of the formula within.

Can Diamond Retinal 25 replace prescription tretinoin?
Diamond Retinal 25 is a cosmetic product and makes no therapeutic claims. However, retinaldehyde is the non-prescription retinoid with the most extensively documented equivalence to prescription-grade tretinoin — achieving comparable improvements in fine lines, skin texture, and pigmentation at lower concentrations and with fewer instances of retinoid dermatitis. At 0.25%, Diamond Retinal 25 operates at the upper boundary of non-prescription retinal therapy. For those seeking to reduce or take breaks from prescription retinoid use, it provides meaningful retinoic acid-adjacent activity in a controlled, non-prescription format. Any decision to modify a prescribed treatment should involve a dermatologist.

Why does Diamond Retinal 25 contain a full ceramide complex when the other advanced serums in the series do not?
The presence of the full ceramide complex in Diamond Retinal 25 is a deliberate formulation response to the demands of 0.25% retinal. At this concentration, retinoic acid-driven cellular turnover is intensive and sustained — transepidermal water loss increases, barrier lipid depletion accelerates, and the risk of barrier compromise is higher than at any previous step in the series. The five-component ceramide complex — Ceramide NP, Ceramide AP, Ceramide EOP, Phytosphingosine, and Cholesterol — provides in-formula barrier repair that sustains skin integrity throughout the overnight renewal process, enabling the 0.25% retinal to operate at maximum efficacy without compromising long-term skin health.