“They sound similar in concept, and you absolutely need both to achieve healthy skin,” says Dr. Ryan Turner, M.D., New York City-based board-certified dermatologist and co-founder of TRNR Skin. As he explains, water is the underlying connection, but their functions are different. “Hydration is all about pulling water into the surface layers of the skin while moisturizing is about trapping it within to support and strengthen its barrier,” he says.

“Hyaluronic acid is a humectant, meaning it attracts water to and retains it in the skin,” Ryan Turner, MD, a board-certified dermatologist in New York City, tells SELF.1 (And a lot of H2O at that: Hyaluronic acid can hold up to 1,000 times its weight in water.)2 Think of it like a sponge; as it pulls in moisture and absorbs it, it puffs up, helping to both hydrate and plump the skin. As a result, your complexion looks smoother and more vibrant, and fine lines may be less noticeable, Dr. Turner says.

“We often say, ‘The answer is in the history,’ when we’re trying to discover the cause of a breakout,” says board-certified dermatologist Ryan Turner, M.D., the founder of Turner Dermatology in New York City. If you went to his office, he would examine the spots but he would also ask a bunch of questions to determine what was going on in the weeks leading up to the breakout. Did you travel? Eat something new? Sample a product at a store? Swim in a pool? Sleep somewhere different?

Both red and blue light therapy are a type of photodynamic therapy, meaning they use light in different wavelengths of the color spectrum to penetrate skin. You may also see them referred to as low-level laser light therapy, cold laser therapy, biostimuation therapy or photobiomodulation therapy. Ryan Turner, M.D., a board-certified dermatologist in New York City calls them “an established part of a number of dermatologists’ treatment protocols.” They’re also used in at-home products as a weekly or even daily treatment.  

What causes acne scars?

First things first, let’s best understand what causes acne scars before diving into how to help treat and remove them.

According to Chwalek, acne scars occur “when there is significant inflammation damaging deeper tissue and resulting in a depressed scar.”

This prolonged inflammation in acne cysts or nodules is most common, although all forms of acne, “including red papular acne (pimples), pustules, white heads and black heads,” per Turner, can also result in scarring. In short, inflammation in the skin causes damage to the collagen in the skin, leading to scarring. “The longer a person delays treatment, the more the risk of scarring,” Turner adds.

If your eczema comes with little cracks in the surface of your skin, what you’re dealing with is likely asteatotic eczema, a subtype of the chronic inflammatory condition that is characterized by fissures in the skin that resemble a cracked desert floor. It’s just one of the many kinds of eczema out there, but also one you should pay close attention to, says Ryan Turner, M.D., an assistant professor of dermatology at the Albert Einstein College of Medicine in New York City. “In severe cases [asteatotic eczema] becomes painful, and the cracks can let bacteria into the skin and lead to infection,” says Dr. Turner.

ummer comes with a lot of excitement, but as far as your skin care is concerned, the season can also come with its fair share of downfalls: an extra greasy complexion, breakouts, and sunburns, to name a few. One issue many people struggle with on their body is thigh chafing, or “skin irritation that occurs when the skin on the inner thighs rub against each other or against clothing,” says New York City-based board-certified dermatologist, Dr. Ryan Turner, M.D. This skin annoyance can occur during physical activities as sweat and moisture exacerbates said friction, but you don’t have to be an enthusiastic exerciser to experience it, as hot, humid weather conditions are primarily responsible for making thigh chafing a real-life problem.

“The hormonal imbalance can cause new hair to grow, or it can influence already existing thinner hairs to become darker and thicker on the face, chest, back and abdomen,” says Ryan Turner, MD, a dermatologist practicing in New York City. 

“The pillowcase you use may have some influence on the development of wrinkles on your face,” reveals Dr. Ryan Turner of Turner Dermatology in New York City, citing fabric as the number one thing to consider before resting your head for the night.

I’m not the only one giving these celebs the side-eye. The proliferation of star-led beauty brands in the past two years has stirred up an understandable backlash. So I asked board-certified dermatologists Kavita Mariwalla, MD, and Ryan Turner, MD. to help me try out eight celebrity lines and read the fine print on all the ingredients lists...our findings surprised us all.