Journal
Longer notes from the blog, numbered like issues of a journal.
- VOL. 14Botulinum toxin resistance: does it really happen?Antibodies against botulinum toxin are uncommon: in a large analysis, about 1 in 200 people developed them. That figure comes from manufacturer studies, though, and antibodies are not the only reason the effect may seem to wear off sooner.Read →
- VOL. 13Cheek hollowing after lifting: what should you check if your face is thin?Having a thin face alone does not rule out lifting, but first you need to tell whether the concern is sagging or volume loss. Both ultrasound and radiofrequency have rare reports of reduced fat under the skin, but no study compared the two directly, so neither can be called riskier.Read →
- VOL. 12When should you apply hyaluronic acid, and can it make skin drier?There is a mechanistic explanation for how hyaluronic acid could leave skin drier, but it has not been measured directly on human skin. What the literature consistently says is that water drawn in will not stay unless you seal it with a layer on top.Read →
- VOL. 11Why does seborrheic dermatitis flare up every season change?Seborrheic dermatitis is described in the literature as a chronic condition that comes and goes, so the goal is to keep it down rather than make it disappear. The data linking it to seasons are hospital statistics from other countries and do not apply directly to Korea’s climate.Read →
- VOL. 10How long does it take for the skin barrier to recover?No study gives a fixed number of days for recovery. In experiments, repair activity peaked on day 3 and rebuilding the layer took longer, but those used a one-time complete strip of the outer layer, which differs from the repeated damage that happens on the face.Read →
- VOL. 09How is facial flushing different from rosacea?Redness that comes and settles down is temporary flushing, while redness that persists without any trigger points toward a diagnosis of rosacea. The idea that “untreated flushing turns into rosacea” has not yet been checked by any study following the same people over time.Read →
- VOL. 08Niacinamide: is a higher concentration better?The evidence that higher concentrations are harmful is weak, and so is the evidence that they work better. Most clinical studies showing effects used 2–5%, so starting within that tested range is reasonable.Read →
- VOL. 07How can you tell seborrheic keratosis (age spots) from a mole?A rough, slightly raised spot you can feel with a fingertip is likely a seborrheic keratosis, and most are benign growths, not cancer. But melanomas that look like seborrheic keratoses do exist, so telling them apart by eye is hard even for doctors.Read →
- VOL. 06Vitamin C serum turned brown: should you throw it away?Vitamin C (L-ascorbic acid) oxidizes and turns brown when exposed to air, light, heat or water, and the color change reflects lost activity. A pale yellow serum can usually still be used, but a deep brown one is unlikely to work, and if the smell or texture has also changed it is better to stop.Read →
- VOL. 05Ultrasound lifting: how much does it actually lift?In a 2023 systematic review, objectively measured changes were in millimeters: brows raised by 0.47–1.7 mm and the area under the chin reduced by 26–45 mm². The change appears gradually over the months it takes collagen to rebuild, so judging after one month is too early. Results varied by study population, device and settings, and the same change cannot be expected for every individual.Read →
- VOL. 04Why does sunscreen not give the SPF on the label?SPF is measured with 2 milligrams applied per square centimeter of skin, but most people apply less than that. So applying an SPF 50 product the usual way likely gives protection closer to the SPF 30 range.Read →
- VOL. 03Why shouldn’t you pop pimples yourself?Touching and squeezing lesions is one of the four risk factors in a tool for assessing atrophic acne scar risk, and the only one of the four you can change today. Squeezing can push some of the contents through the pore wall into the dermis, widening inflammation and leading to dark marks or pitted scars.Read →
- VOL. 02Retinol: when should you use it and when should you take a break?Mild flaking, dryness or brief stinging right after applying are signs you can continue while moisturizing more. Redness that lasts all day, stinging when water touches the skin, oozing or swelling, or thick sheet-like peeling mean you should cut back or stop.Read →
- VOL. 01Why does pigmentation get darker after laser treatment?Darkening around 2–3 weeks after laser treatment is common and is called post-inflammatory hyperpigmentation. Inflammatory signals stimulate pigment cells to make more pigment, and depending on whether it sits in the epidermis or dermis, fading can take weeks to years.Read →