These Popular Skin Care Ingredients Could Be Working Against You

Dermatologists share how.

by Elise Tabin
Adela Loconte/Shutterstock
skin look at markarian spring 2023

Whether it’s a cream or a serum, loading up your skin with the latest products and treatments is seemingly the best course of action to maintain a healthy, glowy complexion — and ward off signs of aging. But all the effort put into achieving good skin can come with the possible downside of unintentional skin damage from some of the most popular ingredients. Before you completely overhaul your skin care routine, it’s important to note not every ingredient harms every skin type; it ultimately depends on what your skin can tolerate. But because the impairing effects of these select commonly used skin care ingredients often fly under the radar, their negative side effects stick around longer.

These seemingly good-for-the-skin ingredients can cause issues such as breakouts, discoloration, redness, itchiness, peeling, and cracking. These side effects are especially exacerbated when overloading the skin with products, a common reaction when dealing with a breakout, for example. "Many people point to their products when it comes to breakouts, but the truth is it's hard to know what's causing it and what's going on," says board-certified dermatologist Corey Hartman. "Using too many products and duplicating your efforts and not realizing it is part of the problem. But everything is not for everybody, which is the issue with many skin trends."

The best way to avoid negatively impacting your skin health is to educate yourself on what's in your products. So how can you know what's causing a skin freak out when more than one product comprises a regular skin care routine? Try the two-week rule. "Don't use any new products for two weeks after starting something. Then, if there is an increase in redness, itchiness, breakouts or something else, take a break," board-certified dermatologist Dhaval G. Bhanusali says. "If it continues or comes back, see a dermatologist and evaluate your allergic profile."

Ahead, TZR dives into the most under-the-radar skin-sabotaging ingredients and what to do if an adverse effect occurs.


Although biotin is easy to obtain from any regular diet, it has become the go-to vitamin for attempting to grow thicker, longer hair and nails, and even improve the skin. Licensed esthetician and founder of Emme Diane Skincare, Emme Linehan, says biotin is a significant trigger for acne-prone skin — unexplainable rashes are a close second. Regardless if biotin is in pill or powder form, the B vitamin can instigate breakouts in one of two ways: speeding up cell turnover rate and creating vitamin B5 deficiencies.

"Biotin supplements, often a cocktail of B vitamins, such as B6, B9, and B12, can accelerate how fast the skin sheds dead skin cells. These vitamins can increase cell turnover by promoting the growth and proliferation of skin cells," Linehan says. "While cellular turnover isn't inherently bad, it can accumulate dead skin cells on the skin surface in those who are acne-prone.”

Linehan says the main issue with biotin is that it blocks the absorption of pantothenic acid, which is necessary for properly regulating the oil glands. Since pantothenic acid and biotin are absorbed in the intestines by the same receptor, high levels of biotin (more than 5,000 micrograms) hinder the absorption of pantothenic acid. "The receptor can only absorb one or the other at any given time. So, if biotin is blocking the absorption of pantothenic acid, the oil glands overproduce sebum," she explains. "Excess oil and hyper-shedding of dead skin cells can clog the pores and lead to breakouts. That’s why biotin is like pouring gasoline on a fire when it comes to cystic and inflamed acne."

On top of all that, Dr. Bhanusali adds that taking biotin at specific doses can mask signs of cardiac abnormalities — not a skin effect but a serious one to take note of. "We always warn patients who consume it regularly about that."

If you can tolerate biotin with nary a blemish, consider yourself lucky. For the rest, dial down the dose of biotin or opt for collagen, which Linehan says is a good source of protein to support healthy hair, skin, and nails. “But it won't create new collagen or grow better hair," adds. Another alternative to consider is niacinamide, which can help with hair growth. Board-certified dermatologist Ava Shamban says the B vitamin is a good antioxidant and anti-inflammatory.

Dr. Hartman adds that some hair vitamins with proprietary blends of studied ingredients are better for COVID-related telogen effluvium or even nursing back to health over-processed hair. "Viviscal Pro is great, and people rave about Nutrafol. Both are beneficial for hair and proven better than biotin alone."

Shea Butter & Coconut Oil

Dehydrated skin craves mega hydration and many formulas turn to shea butter and coconut oil, natural moisturizers. On the body, Dr. Hartman says shea butter and coconut oil are fine, especially since body skin has a different oil composition, is drier, and needs ingredients to strengthen the skin barrier. "But the problem is that these ingredients are comedogenic, so on the face, they can cause clogged pores, breakouts, and make acne worse."

Dr. Bhanusali says that while some skin types can tolerate shea butter well, the formulation, percentages and other ingredients make all the difference. "I like coconut oil for the body, but we see increased breakouts on the face and worsening seborrheic dermatitis in the scalp with it."

For reasons unbeknownst to him, Dr. Hartman says that shea butter (as well as other butter like cocoa butter) has been known in the Black community to fade dark spots. "There's zero science that it does anything for hyperpigmentation,” he says. So, if you're using these ingredients and not seeing pimples, he says diminishing existing dark spots may seem lighter. Yet, when acne is the resulting factor, the inflammation will lead to stubborn pigmentation leaving behind a double-layered problem.

Oily and blemish-prone skin should avoid shea butter and coconut oil at all costs. Other skin types may be able to tolerate the two, but Dr. Hartman says there are better moisturizers for hydration, like ceramides, glycerin, and hyaluronic acid. "There are 25 other better ingredients that I would choose to use before suggesting shea, cocoa butter, or coconut oil on anybody's face," Dr. Hartman says.

Vitamin C

Topical vitamin C is considered the gold standard in antioxidant protection. It can do wonders for the skin, like brightening it, stimulating collagen production, preventing sun damage, and smoothing out uneven texture and tone. However, Linehan says most people don't realize that vitamin C, often listed as L-ascorbic acid in an ingredient deck, is an acid. "Although it is not an exfoliating acid, those with sensitive skin often cannot tolerate it well," Linehan says.

Vitamin C is one of those catch-22 ingredients like retinoids. While its benefits are vast, Linehan says vitamin C stimulates the skin and follicles, which promotes collagen production. "This stimulation can be perceived as irritation or inflammation in those who are acne-prone, creating a cascade effect leading to little inflamed papules. If someone experiences this reaction, the skin eventually acclimates to this stimulation, and the breakouts subside." How long that takes to transpire varies from person to person.

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If vitamin C leaves your skin red, itchy, irritated, or even with small papule bumps, that doesn't mean you have to give up on it altogether. Dr. Shamban says vitamin C in serum formulations tends to be more compatible and tolerable with the skin. "You'll also want to apply in the morning under sunscreen." Alternatively, you can mix vitamin C with moisturizer to create a bit of a barrier so the skin can tolerate it better.

Because there are so many formulations, stabilizations, and concentrations, finding the right match may be a game of trial and error. There are now more stable vitamin C ingredients, such as tetrahexyldecyl ascorbate, which are less acidic and more tolerable by various skin types, including sensitive skin.

The Wrong Combination Of Acids

Skin cycling has served as a lesson on what ingredients should not be paired together, particularly acids. But combination pairings are still occurring at the mercy of mix masters in their bathrooms, which can be detrimental to the skin. Linehan says skin type and sensitivity levels must always be considered when cocktailing any active ingredient, like acids. What works for one person's skin may be different from another.

"The main ingredient people combine are different hydroxy acids, which causes some irritation and skin inflammation," Dr. Hartman says. "These ingredients are all a little drying and irritating in nature. And so are retinoids, so using those together can be detrimental to the skin, which is probably what led to the idea of using one in the morning and one at night instruction (even though retinoids won't make the skin sensitive to the sun)." Likewise, pairing retinol and vitamin C can lead to unnecessary dryness and irritation.

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Another ingredient pairing to dodge is hydroquinone and benzoyl peroxide. When used together, Linehan says this combination can create a staining effect on the skin which can be challenging to fade. In addition, mixing benzoyl peroxide with other ingredients known to irritate the skin, like retinoids (the combination can deactivate both actives) and even vitamin C, can irritate the skin. "On its own, benzoyl peroxide is irritating and can cause a significant irritant contact dermatitis. Patients who use it sometimes can't put their finger on the reason for dermatitis because it's in so many acne products, even over-the-counter ones," Dr. Hartman says.

Dr. Bhanusali says that acids are great when used appropriately but overdoing it can compromise the skin barrier and lead to more harm than good. “For that reason, I usually recommend only using them once or twice weekly to reset things and maintain the skin.”

PPD IN Hair Color

If you’ve ever had your hair colored and walked out of the salon with a flaming red scalp accompanied by a dermatitis-like reaction of extreme itchiness, redness, and even welt-like bumps on the scalp, ears and neck, what’s transpiring is a common skin reaction to PPD (paraphenylenediamine), the chemical used in darker hair dyes responsible for giving it a natural look.

"PPD is a common skin allergen and silent skin damager that many people are allergic to," Dr. Hartman says. Why some people react to PPD in hair dye and others don’t remains a mystery. It could be that the immune system can’t tolerate the ingredient with age or that constant exposure to it builds and builds until the body reacts. "Those who experience a reaction to PPD in one product will probably react to any product with it." The reactionary effect — and potential long-term damage — is serious. "PPD can cause significant inflammation and lead to hair loss if the ingredient gets on the scalp. It doesn't take much to know if it's an ingredient to stay away from."

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A slight adverse reaction to hair color may not warrant a red flag warning that there's a serious issue at hand. But truth be told, for those skin types that can't tolerate PPD, the reactionary effects continually build upon themselves, meaning that each coloring session will amplify the side effects. "Every time your body sees the ingredient, the immune system gets a little smarter, kind of like how Neosporin doesn't work after years and years — it's the same concept with PPD," Dr. Hartman shares. Besides its visible effects on the scalp, Dr. Shamban says PPD can be a carcinogen. “Unfortunately, you don’t know it damages your cells.”

If a hair dye-induced flare-up happens (anything extreme and anaphylactic warrants immediate medical attention), you’ll want to wash the color out of your hair as best as possible. Anti-inflammatories and oral steroids can help take down skin swelling.

If the somewhat simple act of touching up your grays or single process color is too risky, consider PPD-free hair dyes or stick with bleach-based hair lightening techniques like highlights. There’s also the trick of mixing a few packets of Sweet N’ Lo into the color to help neutralize the pH of the solution. Mixing anti-inflammatory creams, like Stop the Burn and Antidot Pro Scalp, into color help to minimize scalp irritation and inflammation. Of course, the safest route is to let your natural color grow in.

Getting acquainted with the inkey lists of your skin care routine will help prevent any ingredients from negatively impacting your skin. But consulting with a board-certified dermatologist before using any new product on your skin is a foolproof way to prevent these unwanted side effects.