Resistance is growing against the theory that essential oils benefit the complexion. These potent, volatile oils are used in many natural skin care lines because their small molecule size lets these oils quickly penetrate the skin. That means they deliver high levels of nutrients. But a growing number of skin care specialists say essential oils inflame skin. Skin care experts are seeing flareups and reactions among patients who make essential oils part of their daily beauty routine.

One problem is that some essential oils trigger a photo-allergic response when exposed to sunlight and cause the skin to redden. The highly active compounds often weaken the skin’s ability to protect by disrupting healthy flora or microbiome.

Another problem is that manufacturers dilute at least 95 percent of essential oils with cheaper oxidized oils, alcohol or turpentine to increase their profits, says one skin care specialist. Adulterating essential oils can produce skin reaction and reduce a product’s performance.

Not everyone is jumping on the anti-essential oils bandwagon. But to avoid risks, look for products formulated with a working understanding of essential oil chemistry. New skin care brands are touting repairing serums completely free of essential oils and other sensitizing ingredients. The new lines use ingredients found in the skin to restore balance.

San Francisco skin care specialist Kristina Holey and veteran chemist Marie Veronique Nadeau are expanding their line of serums in October. The new additions completely free of essential oils include a purifying cleanser, a balancing tonic, a moisturizing complex and a nourishing mask. Ingredients are biomimetic or those found organically in the skin.

Peet Rivko pledges zero irritants. You’ll find absolutely no essential oils, nut oils, floral extracts or other sensitizing ingredients in this plant based line of daily moisturizers and gentle cleansers.

Kirsten King, founder of Oille, tests the base essential oils in her line for 100 percent purity. She sold out of the watermelon and sea salt organic facial milk she debuted this summer. Next month, the certified clinical aromatherapist will introduces three dry clay masks that help to reset and balance skin.

Read More: Skin Care’s Backlash Against Essential Oils, Kristina Holey, Peet Rivko, OilleNatural