COSRX AHA/BHA Refresh Vitamin C Booster Serum Versus Bioverse B320 Ultra Corrective Booster

There are two forms of arbutin and alpha is the better one to reach for: it works at lower amounts, absorbs into skin more easily, and has a strong safety record.

The science backs this up too: lab and animal studies confirm it lowers melanin by blocking tyosinase and the more you use (up to a point), the more it works.

Human studies look good too.

A 2024 trial found a cream with 5% alpha-arbutin and 2% kojic acid worked about as well as a prescription melasma cream but with fewer side effects. Another study showed 2% alpha-arbutin paired with 10% Trihydroxybenzoic Acid Glucoside and sunscreen faded dark spots and melasma without causing irritation.

Concentration-wise, most serums land in the 1-2% range.

The EU's Scientific Committee on Consumer Safety concluded that alpha-arbutin is safe in face creams up to 2% and body lotions up to 0.5%.

Overall, this is a well-studied and low-irritation brightener that's a great pick for anyone dealing with uneven skin tone. It also pairs well with vitamin C, niacinamide, and sunscreen.

Alpha-Arbutin is a brightening molecule with a sugar attached to it. That sugar makes it love water which is great for keeping products stable...but not so great for getting through your skin.

The outer layer of your skin is oily and waterproof by design so water-loving ingredients have a harder time getting past it.

Lab tests using real human skin show only a tiny fraction of the Alpha-Arbutin applied actually made it below the surface. Most of it just sat on top and eventually got washed or rubbed away.

So why bother?

Because it doesn't really need to go far. Pigment gets made just under the surface so even a small amount landing in the right place can slow it down. Studies where people used 2% Alpha-Arbutin along with sunscreen did see dark spots fade. Keep in mind it's just slow so expect months, not weeks.

You might have heard Alpha-Arbutin turns into hydroquinone (a much stronger, prescription-level brightener) once it's on your face. It can happen in theory since bacteria on your skin can break that sugar off.

But the amount was almost nothing when researchers actually measured it on real people. That's why European safety regulators looked at all of this in 2023 and said 2% for face products and 0.5% for body products is fine.

We can tell you a product has Alpha-Arbutin in it but nobody can tell you how much will absorb into your skin. Here's why:

This is why safety regulators test absorption on actual skin in a lab instead of trying to calculate it. If it could be predicted from an ingredient list, they'd do that.

You might have heard of "niacin flush", or the reddening of skin that causes itchiness. Niacinamide has not been found to cause this.

In very rare cases, some individuals may not be able to tolerate niacinamide at all or experience an allergic reaction to it.

If you are experiencing flaking, irritation, and dryness with this ingredient, be sure to double check all your products as this ingredient can be found in all categories of skincare.

When incorporating niacinamide into your routine, look out for concentration amounts. Typically, 5% niacinamide provides benefits such as fading dark spots. However, if you have sensitive skin, it is better to begin with a smaller concentration.

When you apply niacinamide to your skin, your body converts it into nicotinamide adenine dinucleotide (NAD). NAD is an essential coenzyme that is already found in your cells as "fuel" and powers countless biological processes.

In your skin, NAD helps repair cell damage, produce new healthy cells, support collagen production, strengthen the skin barrier, and fight environmental stressors (like UV and pollution).

Our natural NAD levels start to decline with age, leading to slower skin repair, visible aging, and a weaker skin barrier. By providing your skin niacinamide, you're recharging your skin's NAD levels. This leads to stronger, healthier, and younger looking skin.

Another name for vitamin B3 is nicotinamide. This vitamin is water-soluble and our bodies don't store it. We obtain Vitamin B3 from either food or skincare. Meat, fish, wheat, yeast, and leafy greens contain vitamin B3.

The type of niacinamide used in skincare is synthetically created.