TWS BeginS by Jungsaemmool serums: what each one does

A breakout clears in a week, and then the brown mark it leaves sits there for a month. Or your skin shines by noon and still feels tight after you wash it. Those are the two problems behind the TWS BeginS by Jungsaemmool serums, the skincare line the K-pop group TWS fronts as brand models. The campaigns sell each serum with one big promise. Here is what those promises rest on, how the key ingredients work, and how to use each serum so it has a fair chance.

What do the BeginS serums promise?

Speed for one, depth for the other. The Pink Guava Glutathione serum, sold in Korea as a serum for the traces blemishes leave, was launched this summer with the line ‘7일 만에 흔적 잡는 잡티샷 세럼’, roughly the spot-shot serum that catches marks in 7 days, and the slogan ‘Gentle but Powerful.’ The Blue Hydrangea hydration line, a mist and a serum, followed in September with the message ‘10만 캡슐의 힘으로’, roughly with the power of 100,000 capsules, and Korean trade press described its hyaluronic acid as ultra-low-molecular nano spheres.

Both campaigns star TWS. Being the face of a campaign is a paid modeling role, and nothing in the reports says what any member uses on his own skin, so we leave that out. What matters for your skin is the two ingredients the serums are built on: glutathione and hyaluronic acid.

How does glutathione make marks look lighter?

It works on the type of pigment, not on the mark itself. Glutathione is an antioxidant your own cells make. A review of its use on skin explains that its lightening effect is thought to “result from direct as well as indirect inhibition of the tyrosinase enzyme and switching from eumelanin to phaeomelanin production.” In plain terms, it slows the enzyme that starts pigment production and tips what is made toward a lighter, reddish-yellow pigment instead of dark brown. We cover the background in our glutathione entry.

That is why it is aimed at flat marks that stay after a blemish has healed. It is not designed for the breakout itself, or for a raised or pitted scar.

How long does a glutathione serum take to work?

Longer than 7 days. The best human trial we found is small: 30 healthy women aged 30 to 50 used a 2% oxidized glutathione lotion on one side of the face and a placebo on the other, twice a day. The glutathione side had a significantly lower melanin reading from the early weeks through the end of the study at 10 weeks, and the researchers reported “There were no marked adverse effects from GSSG application.” In the second half of the study, that side also had more skin moisture and a smoother surface.

A 2025 review from the US is blunt about how far that goes: “Despite its popularity, scientific research on topical glutathione is limited.” One trial in one group of women is a reason to try a glutathione serum, not proof that it will fade a specific mark in a week.

We could not read the brand’s own ingredient list for the Pink Guava serum, and retailer lists for it do not agree with each other, so we are not naming its other actives or its glutathione level. Check the box sold in your market.

How does hyaluronic acid hydrate tight, dull skin?

It holds water in the skin’s surface layers. A review of hyaluronic acid in skin calls it “The key molecule involved in skin moisture” because of its capacity to retain water. Skin that shines yet feels tight is often short of water rather than oil, which we explain in Can dehydrated skin be oily?

Molecule size, the thing the nano message is about, does matter. On human skin, a Raman imaging study found hyaluronic acid of 20 to 300 kDa passed through the outermost layer, while 1,000 to 1,400 kDa stayed on top. In a 60-day trial in 76 women aged 30 to 60, creams with 0.1% hyaluronic acid in five sizes, used twice a day around one eye, all improved hydration and elasticity compared with a plain cream, and only the two smallest, 50 and 130 kDa, also reduced wrinkle depth. So smaller forms do reach further, and large forms still help hydration from the surface. A count of 100,000 capsules tells you nothing about either.

The Blue Hydrangea mist’s ingredient list on US retailer Dodoskin pairs several forms of hyaluronic acid, including sodium hyaluronate and hydrolyzed hyaluronic acid, with glycerin, panthenol, ceramide NP and fragrance. If fragrance bothers your skin, that last one matters.

Does PDRN in a hydrating mist do anything?

Less than the label suggests, as far as current evidence goes. PDRN, listed as sodium DNA, is a fragment of DNA, and most of its research comes from injections and wound care. A 2026 systematic review concluded that “the evidence base remains limited by small sample sizes, heterogeneous treatment protocols, and variable outcome measures.” A widely cited rule in skin science also holds that compounds generally need to be under 500 daltons to pass the skin’s outer barrier, and DNA fragments are far larger. We cover topical PDRN in PDRN serum for dull, dehydrated skin.

If the Blue Hydrangea mist makes your skin feel plumper, the hyaluronic acid and glycerin are the likelier reason.

How should you use the BeginS serums?

Use each for the problem it was built for, and give it time.

• Pink Guava Glutathione serum: after cleansing and any toner, on the areas with marks or the whole face, every day. Wear sunscreen every morning. Give it 8 to 10 weeks before judging, the length of the trial above. Use one brightening serum at a time; if you already use a tranexamic acid or niacinamide serum, we compare those in Tranexamic acid serum for dark spots.
• Blue Hydrangea mist or serum: on clean, slightly damp skin, then a moisturizer on top. Water-binding ingredients work best under a layer that slows water loss, as we explain in Humectant vs occlusive skincare.
• Both: hydration serum first, brightening serum second, moisturizer last.

Both serums are listed on Amazon US, and YesStyle lists BeginS products with shipping to the US and UK. In searches on October 15 and 16, 2026, we did not find the line at Sephora or Ulta, or at a UK high-street retailer. The pink guava serum appears under two names: Trace Serum and Blemish Serum.

Editor’s note

For the marks my monthly breakouts leave behind, what I rely on is daily care: retinal, bakuchiol, the lotion I got from my dermatologist, and sunscreen applied properly. Once, I layered several melanin-care products at the same time, and my skin answered with dry patches and a rough surface. That is why we suggest one brightening product at a time.

If you would rather start with products we have used, our picks below cover the same two problems: a tranexamic acid and niacinamide serum for marks, and a barrier essence for dehydrated skin.