Alastin HA Immerse Serum Review

Alastin HA Immerse Serum is a hyaluronic acid serum designed to sit at the hydration step of a routine, whether that's a normal morning-and-evening regimen or the gentler routine used after an in-clinic procedure. It combines several forms of hyaluronic acid with peptides and a mushroom-derived extract, in a lightweight, fragrance-free base that's designed to absorb quickly and layer cleanly under moisturiser, SPF and makeup.

Key ingredients

The formula is built around hydration and barrier support rather than active exfoliation or pigment correction, which is why it's positioned as suitable for sensitive and reactive skin.

• High-molecular-weight hyaluronic acid and Sodium Hyaluronate Crosspolymer — sits on the skin's surface to draw in and hold moisture.
• Octapeptide-45 — a peptide included to support the skin's own hydration processes over continued use.
• Hexapeptide-11 — included alongside the HA complex to help support hyaluronic acid levels in the formula.
• Tremella Fuciformis (silver mushroom) extract — a plant-derived humectant, sometimes described as a natural alternative to hyaluronic acid.

What it's formulated to do

The serum is formulated to help improve the appearance of dehydration, dullness and fine lines caused by moisture loss, by adding surface hydration immediately and supporting the skin's moisture barrier with continued use. It's not an anti-pigmentation or resurfacing product, so it won't address tone or texture concerns rooted in cell turnover — pair it with a targeted treatment step if that's what you're after, and use this serum to handle the hydration side of the routine.

Texture and how it wears

The formula is a thin, water-based serum rather than a gel or cream, so it sinks in quickly without leaving a tacky film. That makes it easy to layer under moisturiser, SPF and makeup without pilling, and it doesn't leave the heavier, slightly sticky finish that some richer HA serums can. It's fragrance-free, which is worth noting if you specifically enjoy scented skincare, but it's part of why the formula is well tolerated on reactive skin.

Who it suits

Because it's fragrance-free, non-comedogenic and built around hydration rather than active ingredients, it's positioned as suitable across skin types, including oily and acne-prone skin, and for people who find their skin reactive after using retinoids or exfoliating acids. Its gentle profile is also why it's commonly recommended for post-procedure aftercare. It's a good fit if your main concern is tightness, dullness or dehydration rather than pigmentation, deep wrinkles or breakouts, which are better addressed with a targeted active alongside it.

How to fit it into a routine

Applied to slightly damp skin after cleansing, then followed by a moisturiser to help lock the hydration in. It works well both morning and evening, and layers cleanly underneath SPF, so it doesn't need to be reserved for night-time use only. For a richer routine, it pairs well with the Alastin Ultra Nourishing Moisturiser, using the serum as the hydration layer and the moisturiser to seal it in and add emollience. See our roundup of the best hydrating serums available in the UK for how it compares against other lightweight options if you're still deciding.

Using it after a procedure

Its fragrance-free, low-irritation formulation is a common reason it's chosen for the sensitive skin window immediately after treatments such as microneedling, peels or laser. Skin in this period is more permeable and more easily irritated, so a simple, hydration-focused product with no fragrance or active exfoliants is generally a safer choice than a full routine of actives. For general timing and product choices in that period, see our guide to post-procedure skincare for the first 48 hours — always follow your clinician's specific aftercare instructions first, since these can vary by treatment and by practitioner.

How it compares

Within the Alastin range, it sits alongside the Alastin Regenerating Skin Nectar, which leans more towards barrier repair and skin recovery than pure hydration. If you're deciding between the two, our comparison breaks down which is the better fit depending on whether hydration or recovery is the priority.

Pregnancy and breastfeeding

If you're pregnant or breastfeeding, please contact our team for advice before use.