Collection: Crystal Retinal Range

Both are forms of vitamin A, but they sit at different points on the conversion pathway to retinoic acid — the active form your skin uses. Retinol must undergo two conversion steps in the skin (retinol → retinaldehyde → retinoic acid), while retinaldehyde requires only one. This single-step difference means retinaldehyde is significantly more efficient and has been shown to work up to 11 times faster than retinol at equivalent concentrations. Crystal Retinal uses retinaldehyde, making it the most potent form of vitamin A available without a prescription. For those who want to go further, advanced-protocol r-Retinoate offers an encapsulated retinoic acid ester that bridges the gap between Crystal Retinal and Advanced-Protocol Retinoid.

Your ideal starting strength depends on your retinoid history. If you have never used a retinoid before, start with Crystal Retinal 1 or 3. If you have been using a retinol product regularly for several months, Crystal Retinal 6 is usually appropriate. Strengths 10 and 24 are for experienced retinoid users who have built tolerance over time. If you are unsure, book a free written skin assessment and we will assess your skin and recommend the right starting point. It is always better to start conservatively — you can progress once your skin has adapted.

We recommend using each strength consistently for a minimum of 8 to 12 weeks before considering progression. During that time, use the product nightly (after an initial alternate-night introduction period) and assess how your skin responds. Signs you are ready to move up include: no redness, peeling, or sensitivity on nightly use; consistent tolerance for at least four weeks; and a desire for stronger anti-ageing results. There is no obligation to progress — if your current strength delivers the results you want, staying at that level is perfectly fine.

Absolutely — this is the foundation of Medik8's CSA philosophy. Apply your vitamin C serum in the morning and Crystal Retinal at night. Using them at different times of day avoids any potential pH interaction and ensures each active works optimally. The vitamin C provides daytime antioxidant protection and brightening, while the retinaldehyde works overnight to accelerate cell turnover and stimulate collagen. Together, they deliver comprehensive anti-ageing and skin-health benefits that neither could achieve alone.

Crystal Retinal is formulated to be significantly more tolerable than many retinoid products, thanks to Medik8's time-release crystal encapsulation technology and the inclusion of hyaluronic acid and soothing ingredients. However, retinaldehyde is still an active form of vitamin A, so some adjustment is expected — especially in the first two weeks. For sensitive or rosacea-prone skin, start with Crystal Retinal 1 on alternate nights and build slowly. If irritation persists beyond the first month, it may be worth exploring gentler alternatives or booking a consultation so we can tailor your approach.

Yes — SPF is essential when using any retinoid, including Crystal Retinal. Retinoids accelerate cell turnover, which means fresh, newer skin cells reach the surface faster. These cells are more susceptible to UV damage, so unprotected sun exposure can undo the benefits of your retinoid and increase the risk of hyperpigmentation. Wear a broad-spectrum SPF 30 or higher every morning, even on cloudy days and even if you are indoors near windows. This is the single most important step you can take to protect your results.