Ultima C Serum

A vitamin C serum for face only works if the vitamin C survives long enough to do anything. Ultima C Serum is a vitamin C brightening serum built on 15% pharmaceutical grade vitamin C, paired with hyaluronic acid, and stabilized to hold its potency for up to 48 hours after you open the bottle. It holds a 4.9 star average across 51 reviews, and it's formulated to work across oily, normal, acne prone, combination, sensitive, and dry skin.

Key Ingredients in This Brightening Serum

Full ingredient list: Aqua, Magnesium Ascorbyl Phosphate, 3-Glyceryl Ascorbate, Propanediol, Pentylene Glycol, Xanthan Gum, Lecithin, Sclerotium Gum, Pullulan, Caprylhydroxamic Acid, Caprylyl Glycol, Glycerin, Hyaluronic Acid, Hibiscus Sabdariffa Flower Extract, Lycium Barbarum (Goji Berry) Fruit Extract, Camellia Sinensis Leaf Extract, Terminalia Fernandiana (Kakadu Plum) Fruit Extract, Tetrasodium Glutamate Diacetate, Sodium Bisulfite, Pelargonium Graveolens (Geranium) Flower Oil, Rosmarinus Officinalis Leaf Extract, Hydrolyzed Gardenia Florida Extract, Maltodextrin, Sodium Hydroxide.

The 15% vitamin C comes from two forms, magnesium ascorbyl phosphate and 3-glyceryl ascorbate, working alongside hyaluronic acid and glycerin for hydration. Hibiscus, goji berry, green tea, and kakadu plum, one of the most naturally vitamin C dense fruits in existence, add a layer of antioxidant and brightening support on top of the core formula. It's packaged in a glass bottle, which matters more than it sounds like it should, since vitamin C degrades faster with light exposure than almost any other active ingredient in skincare.

A Different Kind of Vitamin C Serum

Plenty of vitamin C serums are built around l ascorbic acid, often stabilized with vitamin E and ferulic acid, which is effective but notoriously unstable and prone to oxidizing, turning color, and losing potency within weeks. Other brands lean on gentler derivatives instead, like sodium ascorbyl phosphate, ascorbyl glucoside, or tetrahexyldecyl ascorbate, which are more stable but usually used at lower concentrations. Ultima C Serum takes a third approach: magnesium ascorbyl phosphate and 3-glyceryl ascorbate at a genuine 15% concentration, formulated to stay potent for up to 48 hours after opening rather than degrading immediately.

Who This Serum Is For

Ultima C Serum is formulated for oily, normal, acne prone, combination, sensitive, and dry skin, and it's positioned to address dark spots, dullness, fine lines, uneven tone, and loss of firmness. Because it's a water based, oil free serum, it doesn't add excess oil to oily or acne prone skin, and post-acne dark spots are exactly the kind of discoloration a brightening serum like this is meant to fade. Sensitive skin should note that the formula does contain a light natural fragrance from geranium flower oil rather than being fragrance free.

What to Expect, and When

In a six week study, users saw a 35% increase in skin hydration, a 28% improvement in skin roughness and texture, and a 29% improvement in skin luminosity. Some testers note a slight tackiness or sticky residue in the first few minutes after application, which is common with hyaluronic acid containing serums, but the formula fully absorbs within a few minutes, leaving skin feeling smooth rather than tacky.

Directions

Apply evenly to cleansed face and neck daily. SPF use is recommended, since a brightening serum is only doing half its job if new sun damage is undoing the dark spots it's fading. Give it several months of consistent, daily use to see the full effect on skin tone and texture, though hydration and radiance are typically noticeable within the first couple of weeks.

How to Layer It Into Your Skincare Routine

Apply Ultima C Serum to cleansed skin, so start your routine with a gentle cleanser like Sensi Wash. Once the serum has fully absorbed, follow with a daily moisturizer such as Nano Hydrator to lock in the hydration boost from the hyaluronic acid in the formula. Finish every morning with a broad spectrum sunscreen like Day Drops SPF 50; vitamin C and daily sun protection are meant to work together, and skipping the sunscreen step undercuts the brightening results you're working toward.

Common questions about Ultima C Serum:

What form of vitamin C does this serum use?

Ultima C Serum uses magnesium ascorbyl phosphate and 3-glyceryl ascorbate at a 15% concentration, rather than l ascorbic acid or a single lower strength vitamin C derivative. Both forms are chosen for stability as much as potency.

Is this a good vitamin C serum for sensitive skin?

Yes, it's formulated for sensitive skin as well as oily, normal, acne prone, combination, and dry skin. It does contain a light natural fragrance from geranium flower oil, so anyone avoiding all fragrance should be aware of that before use.

Will this help with dark spots and dullness?

Yes, dark spots, dullness, and uneven tone are specifically among the concerns this brightening serum is formulated to address, alongside fine lines and loss of firmness. Consistent daily use over several months delivers the most visible improvement in tone and texture.

Do I need to wear sunscreen with this vitamin C serum?

Yes. SPF use is recommended directly in the directions, since vitamin C works best alongside daily sun protection rather than in place of it, and unprotected sun exposure can work against the dark spot and tone improvements you're using this serum for.

Why does the serum feel slightly tacky when I first apply it?

That's the hyaluronic acid in the formula, which is common in HA containing serums right after application. It fully absorbs within a few minutes, and skin should feel smooth rather than sticky once it does.

Can I use this serum with other active ingredients like retinol?

Vitamin C is generally used in the morning, which makes it easy to pair with a retinol or other active ingredient used at night. If you're introducing multiple new active ingredients at once, a board certified dermatologist can help you sequence a routine that avoids irritation.